Authors: Taís dos Santos da Cruz Walker Vinícius Ferreira do Carmo Batista Eduarda Ferreira de Oliveira Wanessa Lima de Oliveira Dilton Martins Pimentel Gabriel Ali Atta Diab Ivo Freitas Teixeira Marcio César Pereira João Paulo de Mesquita
Cyamelurate anions obtained from the hydrolysis of polymeric graphitic carbon nitride were used for the preparation of a water-stable and crystalline coordination polymer based on nickel(II)–cyamelurate. The polymer was prepared and applied as a catalyst for the reduction of 4-nitrophenol to 4-aminophenol in the presence of borohydride under ambient conditions. The catalyst was prepared by a simple and environmentally friendly method in an aqueous medium, and it was completely characterized by a variety of techniques, including FTIR, UV–Vis, XRD, TGA, TEM, and STEM. The obtained catalyst was able to catalyze the reaction of 4-nitrophenol to 4-aminophenol with a good kinetic constant. In addition, the catalyst proved to be significantly robust, maintaining a conversion rate greater than 80% after five minutes of reaction for eight consecutive catalytic cycles. In addition, the catalytic activity of the coordination polymer was much higher than that observed for a homogeneous catalyst based on aqueous Ni2+ ions, suggesting the importance of the structure of the coordination sphere formed by the cyamelurate anions. The results presented here can contribute to the application of other coordination polymers anchored with cyamelurate-like ligands and derivatives, as well as to new catalyst designs based on this coordination site formed by oxygen and nitrogen donor atoms.
]]>Authors: Saeed Alhawtali Mohanad El-Harbawi Lahssen El Blidi Maher M. Alrashed Abdulrahman Alzobidi Chun-Yang Yin
The removal of lead metals from wastewater was carried out with carbon microspheres (CMs) prepared from date palm leaflets using a hydrothermal carbonization process (HTC). The prepared CMs were subsequently activated with phosphoric acid using the incipient wetness impregnation method. The prepared sample had a low Brunauer–Emmet–Teller (BET) surface area of 2.21 m2·g−1, which increased substantially to 808 m2·g−1 after the activation process. Various characterization techniques, such as scanning electron microscopy, BET analysis, Fourier transform infrared, and elemental analysis (CHNS), were used to evaluate the morphological structure and physico-chemical properties of the CMs before and after activation. The increase in surface area is an indicator of the activation process, which enhances the absorption properties of the material. The results demonstrated that the activated CMs had a notable adsorption capacity, with a maximum adsorption capacity of 136 mg·g−1 for lead (II) ions. This finding suggests that the activated CMs are highly effective in removing lead pollutants from water. This research underscores the promise of utilizing activated carbon materials extracted from palm leaflets as an eco-friendly method with high potential for water purification, specifically in eliminating heavy metal pollutants, particularly lead (II), contributing to sustainability through biomass reuse.
]]>Authors: Danny Otto Nils Matzner
In recent years, research on carbon dioxide removal (CDR) has significantly increased. Numerous studies have analyzed demonstration projects, outlined scenarios, modeled pathways, or focused on CDR’s national or international governance. However, regional case studies investigating the dynamics that may facilitate or impede the broader adoption of CDR methods in spatially explicit settings are critically absent. Understanding implementation contexts on the ground is vital, and comparing them across different removal methods is essential for effectively scaling up CDR. This paper aims to address this research gap by comparatively examining the development of biomass-based CDR in three regions of Germany. Taking an exploratory approach, we conducted surveys in these regions to gain insight into stakeholder perceptions of the following six CDR methods: forest management, agriculture and soil carbon, long-lasting building materials, rewetting of peatlands and paludiculture, biochar, and bioenergy with carbon capture and storage. In this article, we present the results of the stakeholder survey, which offers multiple perspectives that can shape future studies of regional implementation and yield policy-relevant guidance. Although our research primarily focuses on the regional level in Germany, it sheds light on various conflicts, uncertainties, and potentials that are likely to be relevant for the rollout of CDR in other countries. By examining these aspects, we contribute to the broader discourse on CDR and its potential implementation.
]]>Authors: Matteo Strozzi Isaac E. Elishakoff Michele Bochicchio Marco Cocconcelli Riccardo Rubini Enrico Radi
In this study, a new anisotropic elastic shell model with a nonlocal strain gradient is developed to investigate the vibrations of simply supported single-walled carbon nanotubes (SWCNTs). The Sanders–Koiter shell theory is used to obtain strain–displacement relationships. Eringen’s nonlocal elasticity and Mindlin’s strain gradient theories are adopted to derive the constitutive equations, where the anisotropic elasticity constants are expressed via Chang’s molecular mechanics model. An analytical method is used to solve the equations of motion and to obtain the natural frequencies of SWCNTs. First, the anisotropic elastic shell model without size effects is validated through comparison with the results of molecular dynamics simulations reported in the literature. Then, the effects of the nonlocal and material parameters on the natural frequencies of SWCNTs with different geometries and wavenumbers are analyzed. From the numerical simulations, it is confirmed that the natural frequencies decrease as the nonlocal parameter increases, while they increase as the material parameter increases. As new results, the reduction in natural frequencies with increasing SWCNT radius and the increase in natural frequencies with increasing wavenumber are both amplified as the material parameter increases, while they are both attenuated as the nonlocal parameter increases.
]]>Authors: Ewa Gabriel Anna Olejnik Bogna Sztorch Miłosz Frydrych Olga Czerwińska Robert Pietrzak Robert E. Przekop
The following work presents a method for obtaining PLA composites with activated carbon modified using the liquid for fused deposition modeling (L-FDM) method in which two different compounds, i.e., rhodamine and antipyrine, are introduced. Tablets saturated with substances were obtained. Microscopic tests were carried out, and these confirmed the presence of substances that had been introduced into the polymer structure. UV-Vis spectra and observation of the active substance release process confirmed the relationship between the printing speed and the amounts of the compounds liberated from the tablets. Additionally, the contact angle of the PLA with activated carbon composites was characterized. The hydrophilic nature of the obtained composites favors an increase in the amounts of compounds released during the release process, which is a desirable effect. The surfaces and pores of the obtained materials were also analyzed. The incorporation of activated carbon into PLA results in a significant increase in its surface area. Investigations indicate that a novel approach for introducing chemicals into polymer matrices through the L-FDM method holds promise for the prospective fabrication of tablets capable of a controlled and customized release of substances tailored to individual requirements.
]]>Authors: Athanasia K. Tolkou Konstantinos N. Maroulas Dimitrios Theologis Ioannis A. Katsoyiannis George Z. Kyzas
Wastewater treatment has attracted much attention in recent years as a potential source of water, and there are some concerns about its safety for human use. Eco-friendly and cost-effective adsorbent materials were successfully synthesized from several peels, such as orange, banana, pomegranate, avocado, kiwi, etc., and were used as natural adsorbents or as activated carbons derived from these peels for water and wastewater treatment. In this review, the latest research focusing on the effective modification of these peels for the removal of several pollutants found in wastewaters are summarized and compared, such as pharmaceuticals, dyes, heavy metals, and anions that are released in waste and have a negative impact on human and animal health. In this review, focus is given to activated carbon produced from fruit peels. Moreover, fruit peels as adsorbent materials, without previously being converted to activated carbon, are of limited use in the recent literature.
]]>Authors: Giuseppe Ruscica Fabio Peinetti Isabella Natali Sora Patrizia Savi
Biochar (bio-charcoal) is a low-cost and eco-friendly material. It can be obtained by thermochemical conversion of different biomass sources, for example, in the total absence of oxygen (pyrolysis) or in oxygen-limited atmosphere (gasification). The porous carbonaceous structure of biochar, resulting from the thermal treatment, can be exploited in cement-based composite production. By introducing biochar powder or other fillers in the cement paste, it is possible to enhance the shielding properties of the cement paste. The environmental impact of polyvinyl chloride (PVC) can be reduced by reusing it as a filler in cement-based composites. In this work, cement-based composites filled with different percentages of biochar and PVC are fabricated. The scattering parameters of samples with 4mm thickness are measured by mean of a rectangular waveguide in the C-band. The shielding effectiveness of reference samples without any filler and samples with biochar and PVC is analyzed. A combination of 10 wt.% biochar and 6 wt.% PVC provides the best shielding performance (around 16 dB).
]]>Authors: James A. Behan Frédéric Barrière
Polypyrrole films are commonly prepared as conductive electrode surfaces for a variety of applications. Recently, there has been increasing interest in improving the adhesive properties and biocompatibility of polypyrrole electrodes via the incorporation of bioinspired polydopamine within the polymer scaffold. However, very little is currently known about the structural effects of polydopamine incorporation during the electropolymerisation of hybrid films. In this work, we combine electrochemical quartz crystal microbalance studies, fundamental electrochemical characterisation, atomic force microscopy, and a suite of spectroscopic techniques in order to correlate changes in the structure and performance of polypyrrole–polydopamine films to the structural modifications of the nanostructure induced by polydopamine incorporation. The results indicate that polydopamine incorporation greatly increases the rate of hybrid film deposition, as well as improving adhesion, surface homogeneity, and wettability, with no compromise in charge transfer properties. Polydopamine incorporation is strongly suggested to occur in non-connected domains within a predominantly polypyrrole-like scaffold. We propose a two-step model of co-polymerisation and the subsequent surface adhesion of hybrid films. Results are expected to be of broad general interest to researchers utilizing polypyrrole and polydopamine to prepare tailor-made electrodes for biosensing and catalysis.
]]>Authors: Batuhan Mulla Kyriacos Ioannou Gkerman Kotanidis Ioannis Ioannidis Georgios Constantinides Mark Baker Steven Hinder Christian Mitterer Ioannis Pashalidis Nikolaos Kostoglou Claus Rebholz
The removal of contaminants from aqueous solutions by adsorption onto carbonaceous materials has attracted increasing interest in recent years. In this study, pristine and oxidized activated carbon (AC) fabrics with different surface textures and porosity characteristics were used for the removal of crystal violet (CV) dye from aqueous solutions. Batch adsorption experiments were performed to investigate the CV adsorption performance of the AC fabrics in terms of contact time, temperature, adsorbate concentration and adsorbent amount. Evaluation of the thermodynamic parameters and the adsorption performance of the AC fabrics in ground water and sea water solutions were also carried out. Langmuir isotherm model, pseudo first and pseudo second order kinetics models were utilized to analyze and fit the adsorption data. The introduction of oxygen-based functional groups on the surface of AC fabrics was carried out through a nitric acid treatment. This oxidation process resulted in a significant reduction in the surface area and pore volume, along with a small increase in the average pore size and a significant enhancement in the CV adsorption capacity, indicating that the dye molecules are mainly adsorbed on the external surface of the carbon fabrics. The herein evaluated 428 mg/g adsorption capacity at 55 °C for the oxidized non-woven AC fabric is one of the highest adsorption capacity values reported in the literature for CV removal using AC materials. Thermodynamic studies showed that the adsorption occurs spontaneously and is an endothermic and entropy-driven reaction. Furthermore, pristine and oxidized non-woven AC fabrics displayed more than 90% CV uptake from sea water samples, underlining the great potential these fabrics possess for the removal of dyes from natural/multicomponent waters.
]]>Authors: Ken-ichi Sasaki Kenichi Hitachi Masahiro Kamada Takamoto Yokosawa Taisuke Ochi Tomohiro Matsui
Monolayer graphene absorbs 2.3 percent of the incident visible light. This “small” absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of incident light, which causes non-negligible fluorescence. In this paper, we formulate the light emission properties of multilayer graphene composed of tens to hundreds of layers using a transfer matrix method and confirm the method’s validity experimentally. We quantitatively explain the measured contrasts of multilayer graphene on SiO2/Si substrates and find sizable corrections, which cannot be classified as incoherent light emissions, to the reflectance of visible light. The new component originates from coherent emission caused by absorption at each graphene layer. Multilayer graphene thus functions as a partial coherent light source of various wavelengths, and it may have surface-emitting laser applications.
]]>Authors: Prakash Giri Irwin Gill Morgan Swensgard Alexandra Kaiser Audrey Rust Brian Stuparyk Andrew Fisher Justice Williams Katie Renoit Eleanor Kreeb Corentin Lavenan Mark J. Schulz
A carbon nanotube (CNT) sheet is a nonwoven fabric that is being evaluated for use in different textile applications. Several properties of pristine CNT sheets and CNT sheets coated with a polysilazane sealant and coating were measured and compared in the paper. The polysilazane coating is used to reduce the shedding of CNT fibers from the sheet when the sheet is in contact with surfaces. Most fabrics show some shedding of fibers during the washing or abrasion of the fabric. This study showed that the coating reduces the shedding of fibers from CNT fabric. The coating also increased the flame resistance of the fabric. The pristine and coated sheets both have low strength but high strain to failure. The pristine and coated CNT sheet densities are 0.48 g/cc and 0.65 g/cc, respectively. The pristine CNT sheet is approximately 27 μ thick. The coated sheet is approximately 24 μ thick. The coating may have densified the sheet, making it thinner. The thickness of the compliant sheets was difficult to measure and is a source of error in the properties. Characterization results are given in this paper. The results are for comparison purposes and not to establish material properties data. Possible applications for CNT sheets are briefly discussed.
]]>Authors: Bruno Alderete Frank Mücklich Sebastian Suarez
The rise in electrification has considerably increased the demand for high-efficiency and durable electrical contact materials. Carbon nanoparticles (CNP) are a promising coating material due to their intrinsic transport properties (thus minimizing the impact on conductivity), their proven solid lubricity (potentially improving tribological performance), and their hydrophobic wetting behavior (potentially providing atmospheric protection). In this study, carbon nanotube and nanohorn coatings are produced via electrophoretic deposition on silver-plated surfaces, followed by tribo-electrical and wetting characterization. The proposed coatings do not negatively affect the conductivity of the substrate, showing resistance values on par with the uncoated reference. Tribo-electrical characterization revealed that the coatings reduce adhesive wear during fretting tests while maintaining stable and constant electrical contact resistance. Furthermore, CNP-coated surfaces show a hydrophobic wetting behavior toward water, with graphite and carbon nanotube (CNT) coatings approaching super-hydrophobicity. Prolonged exposure to water droplets during sessile drop tests caused a reduction in contact angle (CA) measurement; however, CNT coatings’ CA reduction after five minutes was only approximately 5°. Accordingly, CNP (specifically CNT) coatings show auspicious results for their application as wear and atmospheric protective barriers in electrical contacts.
]]>Authors: Md Ainul Kabir Sharfuddin Ahmed Khan Golam Kabir
The technology called carbon capture, utilization, and storage (CCUS) is important for capturing CO2 emissions before they enter the air. Because everyone wants to stop global warming by reducing CO2 emissions, CCUS is an important and emerging technology that can help slow down climate change, lower emissions in many areas, and support the move toward a sustainable and carbon-neutral future. As CCUS technology and its adaptation increases, it is very important to pay attention to the CCUS risks from a supply chain (SC) point of view. The goal of this study was to identify CCUS supply chain risks and develop a conceptual framework (CF) that provides a structured approach to ensure safe and reliable CCUS supply chain operations. Therefore, this study analyzed the literature related to the SCs of different sectors and identified the SC risks, which was the foundation for CCUS SC risk identification. This study demonstrates that there is no research article that provides a comprehensive CCUS SC risk management framework that connects with risk management strategies. The conceptual framework that is proposed in this study connects CCUS SC functions, risks, and risk management strategies to construct a complete CCUS supply chain risk management system. Moreover, the CF provides guidelines for future research, which will enrich the CCUS supply chain risk management system as well as fight climate change.
]]>Authors: Jagdish Narayan
We present the atomic structures and nonequilibrium synthesis of a new class of materials, where the basic structural unit is a diamond tetrahedron. When units of one, two, and three tetrahedra are randomly packed, we create distinct phases of amorphous Q-carbon. Four tetrahedra in two adjacent layers lead to crystalline diamond lattice, which has four missing tetrahedra alternately. When these four missing tetrahedra are filled, we create subunit cell of crystalline Q-diamond. Theoretical calculations show that the superconducting transition temperature (Tc) in 50 atomic % B-doped Q-diamond can reach room temperature at ambient pressures. This is consistent with our earlier results using low-loss EELS measurements in 50 atomic % B-doped Q-carbon, which had mostly amorphous QB3 phase mixed with some crystalline Q-diamond phase. These EELS results showed that the Tc for these samples was between 90 K and 300 K. Theoretical calculations of density of states, Eliashberg function, electron–phonon interaction parameter, and root-mean-square and logarithmic average of frequency in crystalline Q-diamond show Tc in the range of 268 K to 300 K, which is in complete agreement with our EELS results in QB3.
]]>Authors: Neeraj Gupta Ilaria Barlocco Oleksiy Khavryuchenko Alberto Villa
Nitrogen-rich carbon nanotubes NCNT700 and NCNT800 were prepared using the chemical vapor deposition method (CVD). The catalysts were characterized via high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. Both the catalysts were found to have an inverted cup-stack-like morphology. The XPS analysis revealed that the catalysts are rich in pyridinic sites with variable amounts of nitrogen on their surface. The NCTN700, with a higher nitrogen content and more pyridinic sites on its surface, was found to be a good catalyst for the oxidation of benzyl and veratryl alcohols into respective aldehydes. It was observed that toluene and 4-methyl veratrole were also produced in this reaction. The amount of toluene produced was as high as 21%, with 99% conversion of benzaldehyde in the presence of NCNTs-700. The mechanistic pathway was revealed through DFT studies, where the unusual product formation of aromatic alkanes such as toluene and 4-methyl veratrole was explained during the reaction. It was astonishing to observe the reduced product in the reaction that proceeds in the forward direction in presence of a peroxide (tert-butyl hydroperoxide, TBHP). During the computational analysis, it was revealed that the reduced product observed in the reaction did not appear to proceed through a direct disproportionation reaction. Rather, the benzyl alcohol (the reactant) used in the reaction may undergo oxidation by releasing the hydrogen radicals. The hydrogen atoms released during the oxidation reaction appear to have been trapped on pyrrolic sites on the surface of catalyst and later transferred to the reactant molecules to produce toluene as a side product.
]]>Authors: Chengwei Zhou Fan Wu Yonggong Tang Boyuan Chai Jiaxin Liang Jiangang Han Weinan Xing Yudong Huang Guangyu Wu
Photocatalytic carbon dioxide conversion is a promising method for generating carbon fuels, in which the most important thing is to adjust the catalyst material to improve the photocatalytic efficiency and selectivity to conversion products, but it is still very challenging. In order to enhance the efficiency of CO2 photoreduction, it is important to develop an appropriate photocatalyst. The present study focuses on developing a simple and effective hydrothermal reaction treatment to improve the catalytic efficiency of transition metal cobalt (Co) and organophosphonates. Photoexcited charge carriers are separated and transferred efficiently during this treatment, which enhances CO2 chemisorption. Under visible light exposure, the best performing catalyst, CoP-4, showed 2.4 times higher activity than Co3O4 (19.90 μmol h−1 g−1) for reducing CO2 into CO, with rates up to 47.16 μmol h−1 g−1. This approach provides a viable route to enhancing the efficiency of CO2 photoreduction.
]]>Authors: Jesús Noé Rivera Olvera Luis Hernández Maya Lucia Graciela Diaz Barriga Arceo
In the present work, the synthesis and decomposition of low-dimensional materials from a Ni15Mo25W10C50 system produced by mechanical alloying was reported. During the milling process, the resultant phases were WMoC and NiC, and after sintering and quenching, MoNi3, WMo, Ni4W, WC, MoNi and Mo2C were found. The samples were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Nanotubes with the lengths ranging from 500 nm to 2 μm, spheres and novelty globular particles with sizes ranging from 40 to 600 nm as well as “petal-like” estructure were observed. The results revealed the formation of a microstructure with morphology similar to spinodal decomposition followed by a sequence of invariant reactions leading the production of modulated and novel branched structures. We proposes a theoretical mechanism of formation that is associated with the modulated structure observed after quenching.
]]>Authors: Xiaohu Zhou Xiaochen Liu Linlin Sun Xinyu Jia Fei Tian Yueqin Liu Zhansheng Wu
Biochar is a biomaterial obtained by pyrolysis with high porosity and high specific surface area (SSA), which is widely used in several fields. The yield of biochar has an important effect on production cost and utilization efficiency, while SSA plays a key role in adsorption, catalysis, and pollutant removal. The preparation of biochar materials with better SSA is currently one of the frontiers in this research field. However, traditional methods are time consuming and laborious, so this paper developed a machine learning model to predict and study the properties of biochar efficiently for engineering through cross-validation and hyper parameter tuning. This paper used 622 data samples to predict the yield and SSA of biochar and selected eXtreme Gradient Boosting (XGBoost) as the model due to its excellent performance in terms of performance (yield correlation coefficient R2 = 0.79 and SSA correlation coefficient R2 = 0.92) and analyzed it using Shapley Additive Explanation. Using the Pearson correlation coefficient matrix revealed the correlations between the input parameters and the biochar yield and SSA. Results showed the important features affecting biochar yield were temperature and biomass feedstock, while the important features affecting SSA were ash and retention time. The XGBoost model developed provides new application scenarios and ideas for predicting biochar yield and SSA in response to the characteristic input parameters of biochar.
]]>Authors: Jean-Luc Meunier Jeanne Ouellet Kaustubh Basu Alessio Aufoujal Richard Boudreault Jason Robert Tavares
A simple method is presented for the continuous generation of carbon nanotube forests stably anchored on stainless-steel surfaces using a reactive-roll-to-roll (RR2R) configuration. No addition of catalyst nanoparticles is required for the CNT-forest generation; the stainless-steel substrate itself is tuned to generate the catalytic growth sites. The process enables very large surfaces covered with CNT forests to have individual CNT roots anchored to the metallic ground through primary bonds. Fog water harvesting is demonstrated and tested as one potential application using long CNT-covered wires. The RR2R is performed in the gas phase; no solution processing of CNT suspensions is used, contrary to usual R2R CNT-based technologies. Full or partial CNT-forest coverage provides tuning of the ratio and shape of hydrophobic and hydrophilic zones on the surface. This enables the optimization of fog water harvesters for droplet capture through the hydrophobic CNT forest and water removal from the hydrophilic SS surface. Water recovery tests using small harp-type harvesters with CNT-forest generate water capture of up to 2.2 g/cm2·h under ultrasound-generated fog flow. The strong CNT root anchoring on the stainless-steel surfaces provides opportunities for (i) robustness and easy transport of the composite structure and (ii) chemical functionalization and/or nanoparticle decoration of the structures, and it opens the road for a series of applications on large-scale surfaces, including fog harvesting.
]]>Authors: Manish Kumar Gautam Tamal Mondal Rupashri Nath Bidhan Mahajon Mukesh Chincholikar Anirbandeep Bose Dibya Das Rakesh Das Sandip Mondal
Water contamination is a pervasive global crisis, affecting over 2 billion people worldwide, with pharmaceutical contaminants emerging as a significant concern due to their persistence and mobility in aquatic ecosystems. This review explores the potential of activated hydrochars, sustainable materials produced through biomass pyrolysis, to revolutionize the removal of pharmaceutical contaminants from water sources. These materials possess high surface area, porous structure, and exceptional adsorption capabilities, making them a promising solution. The impact of pharmaceutical contaminants on aquatic ecosystems and human health is far-reaching, affecting biodiversity, water quality, and public health. To address this complex issue, a diverse range of techniques, including adsorption, biodegradation, and advanced oxidation processes, are employed in the pharmaceutical industry. Activated hydrochars offer substantial adsorption capacity, sustainable feedstock origins, and a minimal carbon footprint. This review highlights their potential in pharmaceutical contaminant removal and their broader applications in improving soil and air quality, resource recovery, and sustainable waste management. Interdisciplinary collaboration and the development of intelligent treatment systems are essential to fully unlock the potential of activated hydrochars. Regulatory support and policy frameworks will facilitate their responsible and widespread application, promising a cleaner and more sustainable future. This paper aims to inform scientists, environmental experts, policymakers, and industry stakeholders about the promising role of activated hydrochars in addressing pharmaceutical contaminant challenges.
]]>Authors: Yibo Cui Luoyi Liu Mengna Shi Yuhao Wang Xiaokai Meng Yanjun Chen Que Huang Changcheng Liu
Graphene quantum dot (GQD) is a new type of carbon nanometer material. In addition to the excellent properties of graphene, it is superior due to the quantum limit effect and edge effect. Because of its advantages such as water solution, strong fluorescent, small size, and low biological toxicity, it has important application potential in various fields, especially in sensors and biomedical areas, which are mainly used as optical electrical sensors as well as in biological imaging and tumor therapy. In addition, GQDs have very important characteristics, such as optical and electrical properties. There are many preparation methods, divided into top-down and bottom-up methods, which have different advantages and disadvantages, respectively. In addition, the modification methods include heterogeneous doping, surface heterogeneity, etc. There are still many challenges in developing GQDs. For example, the synthesis steps are still hard to conduct, but as the inquiry continues to deepen, GQDs will be revolutionary materials in the future. In this work, the literature concerning research progress on GQDs has been reviewed and summarized, while the key challenges of their application have been pointed out, which may bring new insights to the application of GQDs.
]]>Authors: Simeng Li Desarae Tasnady Shannon Skelley Blanca Calderon Sherine Jiang
In recent times, biochar has emerged as a promising and sustainable solution for COD reduction in wastewater treatment. This study explores the potential of chemically modified biochars as efficient adsorbents for the removal of organic contaminants, specifically oils, fats, and grease (OFG), from wool scouring wastewater. Proximate analysis revealed distinct properties among the biochars, with KOH-treated biochar demonstrating the most promising characteristics, including lower volatile matter, higher fixed carbon content, and reduced ash content, indicating a stable and carbon-rich structure. A meticulous examination of the KOH-treated biochar’s surface characteristics revealed the presence of elevated carbon and nitrogen content, complemented by an expansive surface area measuring 724.4 m2/g. This surface area was at least twice as extensive as that observed in the other post-treated biochar samples. The kinetic adsorption of COD and soluble COD was well fitted by the pseudo-first-order model, with equilibrium achieved in approximately 200 min. The KOH-treated biochar exhibited the highest equilibrium adsorption capacities for both COD and soluble COD in both Dorset wool (Dorset) and Bluefaced Leicester (BFL) wastewater, highlighting its efficacy in OFG removal. Despite these promising results, further research is needed to explore biochar’s surface characteristics, pore structure, and performance under diverse conditions, as well as its integration with existing treatment processes and potential for regeneration and reuse. This study contributes to advancing sustainable wastewater treatment methods using chemically modified biochars.
]]>Authors: Raffaella Soave Fausto Cargnoni Mario Italo Trioni
We conducted a large set of ab initio density functional theory computations to model a variety of hammer-terminated graphene nanoflakes—finite counterparts of armchair graphene nanoribbons. We focused on the relationships among the length and width of the nanoflakes, the stoichiometry and the conformation of the hydrogen saturation of the caps, and the resulting electronic structure. The energetics and the thermodynamic stability of the nanoflakes were investigated as well. Based on this study, we provide a recipe for determining the most stable saturation of the dangling bonds at the caps, which is generally disregarded in theoretical studies, and we prove that this step is crucial for a reliable description of the electronic structure of these systems. Data analysis proved that flakes far from the most stable C–H pattern exhibited electronic properties that were typical of an unsaturated bonding structure. Based on thermodynamics, we also proved that, for any given flake, there was a well-defined hydrogen content and a conformation of H atoms at the caps, which were favored across a wide range of environmental conditions.
]]>Authors: Jobair Al Rafi Yu Kanda Mitsuhiro Honda Yo Ichikawa
The hybrid structure of Graphene and ZnO (Graphene/ZnO) is emerging as a novel material used to achieve the high performance of photocatalysis. In this study, we examined the ZnO characteristics that affect the photocatalytic activity of graphene/ZnO using a lamellar structure of graphene and ZnO thin films. Graphene samples were synthesized via chemical vapor deposition, and a typical wet process was applied to transfer them on sputter-deposited ZnO thin films with and without annealing. We confirmed that graphene-deposited ZnO demonstrated more efficient photocatalytic behavior toward the decomposition of methylene blue (as a model organic compound) with ordinary sputtered ZnO thin films. Again, ZnO thin films annealed at 1000 °C in an N2 gas atmosphere with graphene performed better than unannealed films. XRD analysis confirmed that pre-thermal treatment of a ZnO thin film promoted re-crystallization, which had less impact on the photocatalytic improvement. The attachment of graphene to the film is considered to contribute to the enhancement. Raman analysis revealed that the graphene coverage areas on the post-annealed ZnO increased by two times compared to that of an unannealed film where the unannealed film had a higher graphene layer. The results presented in this study demonstrate that an annealed ZnO thin film forms a better attachment with graphene, resulting in a larger graphene coverage area with fewer multilayers, which effectively improves the photocatalytic activity in composite structures.
]]>Authors: Marie Colin Hani Farhat Sam Chen Elodie Petit Emmanuel Flahaut Katia Guérin Marc Dubois
Sulphur-doped graphene was fluorinated using molecular fluorine (F2). First, the fluorination conditions were adapted in order to be mild enough to maintain S in the carbon lattice and form S-F bonds. An unusually weakened C-F bonding for an F/C ratio of 0.71 was then achieved, which allowed enhanced performances when used as a cathode in primary lithium batteries. The material prepared at a moderate fluorination temperature of 70 °C for a period of 60 min exhibits a high mid-discharge reduction potential of 3.11 V at 10 mA/g and a power density of 3605 W/kg at a discharge rate of 2C. These electrochemical properties make the fluorine/sulfur co-doped graphene a promising material.
]]>Authors: Jafar Sufian Mohammad Babaakbari Sari Filippo Marchelli Luca Fiori Armen Avanes Salahedin Moradi
Chlorella vulgaris is an inexpensive microalga that could be employed for environmental remediation, but further investigations are needed to assess its suitability and optimal treatment methodology. With this aim in mind, this study focused on the raw biomass and the biochar and hydrochar obtained from it, analyzing their physicochemical properties and testing them to capture cadmium from an aqueous environment. The adsorption/absorption tests assessed the effect of adsorbent dosage, pH, Cd concentration, and contact time, and the results were analyzed through a structural equation model. Biochar and hydrochar performed similarly and better than the raw biomass, with the highest Cd removal observed at an adsorbent dosage of 0.8 g L−1, an initial concentration of Cd solution of 30 mg L−1, a pH of 6, and a contact time of 30 min. The adsorption isotherm data for Cd could be well-described by the Langmuir and Temkin models. The results from the structural equation modeling revealed that the variables material type, dosage, and concentration all contributed to Cd removal in water, with time mediating these effects.
]]>Authors: Lin Ge Sharath Chandra Talha Zafar Simon S. Park
The considerable expenses associated with carbon fiber (CF) production have imposed limitations on its widespread application across diverse industries, primarily due to the costs of precursor materials and energy−intensive post−treatment procedures. This research explores the potential utilization of Alberta oilsands asphaltenes (AOAs), a carbon−rich by−product derived from oilsands extraction, as a more cost−effective precursor for CF production. Polystyrene and poly(styrene–butadiene–styrene) were also used as polymer additives. In addition to conventional thermal post−treatment, microwave plasma was employed for the carbonization process. The CFs generated through this approach were subjected to a comprehensive analysis involving SEM, FTIR, TGA, XRD, and Raman spectroscopy. The best tensile strength and Young’s modulus of the AOA carbon fibers when using conventional thermal post−treatment were 600 MPa and 70 GPa, respectively. The microwave plasma process indicates the higher temperature and promise of eliminating heteroatoms of AOA carbon fibers. The temperature for microwave plasma modelling was set using COMSOLTM, with the modelling temperature and detection temperature being established at 1600 K and 1568 K, respectively.
]]>Authors: Hongli Ye Shuangxi Liu Dongmei Huang Chaojun Jiang Rui Yuan Cui Zhang
The accumulation of waste tires has resulted in very urgent environmental problems. Pyrolysis has been regarded as a green eco-friendly technology to deal with waste tires, and it is vital to make use of the pyrolysis carbon. Herein, we propose a new way to utilize pyrolysis carbon, to prepare carbon nanotubes with the help of ferrocene. The optimal preparation processes were determined by optimizing the parameters including the solvent, temperature, time, etc. The results of scanning electron microscopy and transmission electron microscopy evidenced the successful formation of carbon nanotubes. Meanwhile, the Brunauer–Emmett–Teller (BET) method and N2-adsorption showed that the yielded carbon nanotubes featured a large surface area and abundant pore structure in comparison with the pyrolytic carbon. Finally, the as-prepared carbon nanotubes were applied as the supports for Pt-based catalysts for the dehydrogenation of methylcyclohexane to produce hydrogen. The results showed that the Pt/carbon-nanotubes catalyst exhibited the highest conversion of methylcyclohexane (28.6%), stability, and hydrogen evolution rate (336.9 mmol/gPt/min) compared to the resulting Pt/commercial-activated-carbon (13.6% and 160.2 mmol/gPt/min) and Pt/pyrolytic-carbon catalysts (0.19% and 2.23 mmol/gPt/min).
]]>Authors: Nikolay V. Lobus Maria A. Knyazeva Anna F. Popova Maxim S. Kulikovskiy
Since the Industrial Revolution, human economic activity and the global development of society in general have been heavily dependent on the exploitation of natural resources. The use of fossil fuels, deforestation, the drainage of wetlands, the transformation of coastal marine ecosystems, unsustainable land use, and many other unbalanced processes of human activity have led to an increase both in the anthropogenic emissions of climate-active gases and in their concentration in the atmosphere. It is believed that over the past ~150 years these phenomena have contributed to an increase in the global average temperature in the near-surface layer of the atmosphere by ~1 °C. Currently, the most pressing tasks facing states and scientific and civil societies are to reduce anthropogenic CO2 emissions and to limit the global air temperature increase. In this regard, there is an urgent need to change existing production systems in order to reduce greenhouse gas emissions and to sequester them. In this review, we consider up-to-date scientific approaches and innovative technologies, which may help in developing roadmaps to reduce the emissions of climate-active gases, control rising temperatures, decarbonize economies, and promote the sustainable development of society in general.
]]>Authors: Tomás E. Byrne Prudente Diandra Mauro Julieta Puig Facundo I. Altuna Tatiana Da Ros Cristina E. Hoppe
Films of a vitrimer based on the reaction between diglycidylether of bisphenol A and glutaric acid in the presence of 1-methylimidazole were processed using a solvent-based technique. The curing schedule was divided into two steps: first, a soluble linear polymer was formed through the reaction of the diacid and the diepoxide, and then the crosslinking was induced at a higher temperature via transesterification reactions. This epoxy–acid vitrimer was modified with multi-walled carbon nanotubes (MWCNTs) functionalized with β-hydroxyesters, produced by a robust and straightforward strategy based on a two-phase reaction between oxidized MWCNTs and phenylglycidylether. Nanocomposite vitrimer films were obtained by drop casting a dispersion of the functionalized MWCNTs in the linear polymer/cyclohexanone solution, followed by a thermal treatment. A high degree of dispersion of the carbon nanostructures was attained thanks to the β-hydroxyester functionalization when compared with oxidized MWCNTs. Nanocomposite films showed a significant photothermal effect (reaching 200 °C or above in 30 s) upon NIR light irradiation (850 nm) from a single LED (500 mW/cm2). The released heat was used to activate the shape memory effect and weld and heal the vitrimer matrix, proving the success of this easy strategy for the generation of remotely activated carbon-based vitrimer nanocomposites.
]]>Authors: Deepak Deepak Vennela Vuruputuri Gourav Bhattacharya James A. McLaughlin Susanta Sinha Roy
The advancement of renewable energy technologies like water electrolysis and hydrogen fuel cells relies on the fabrication of effective and reliable catalysts for the hydrogen evolution process (HER). In this regard, we report gold nanoparticles embedded in laser-induced graphene electrodes for regulation of overpotential and electrocatalytic performance of hydrogen evolution reaction. Gold nanoparticles were deposited onto the LIG surface using electrode deposition via cyclic voltammetry (CV) at different cycle lengths. The catalyst fabrication technique enables the manipulation of many electrochemical parameters, such as overpotential value, charge transfer resistance, electrochemical active surface area, and tafel slope, through the adjustment of cyclic voltammetry (CV) cycles. The LIG-Au@50 sample demonstrates remarkable electrocatalytic characteristics, as evidenced by its low overpotential of 141 mV at a current density of 10 mA/cm2 and reduced tafel slope of 131 mV/decade in an acidic environment. Furthermore, the presence of an augmented electrochemical active surface area, a mass activity of 8.80 A/g, and a high turnover frequency of 0.0091 s−1 suggest elevated and significant accessibility to plentiful active sites. A significant decrease in charge transfer resistance resulted in an enhanced rate of the water-splitting reaction.
]]>Authors: Zhihong Liu Weitao Cao Man Zhang Wenke Zhao Yaning Zhang
Due to the rapid growth of the global economy, energy consumption has been steadily increasing, leading to increasing issues such as energy shortages and environmental concerns. Biomass energy, a critical renewable energy source, plays a vital role in advancing low-carbon energy development and resource sustainability. In this study, experiments were conducted to study the migration of C, H, and N elements of corn straw during the microwave heating process, and the effects of residence time, heating temperature, and microwave power were also investigated. The results showed that when the temperature rose, both the proportion of C and H elements fluctuated slightly. Specifically, when the temperature rose from 75 °C to 275 °C, there was a 1.02% increase in the proportion of the C element and a 0.25% decrease in the proportion of the H element. Residence time appeared to be a significant factor influencing the changes in C, H, and N elements. For a 40 min residence time, the proportion of the C element increased from 31.77% to 35.36%, while the proportion of the H element decreased from 4.50% to 3.83%. When there was an increase in the microwave power between 160 W and 200 W, higher temperatures were reached in the samples, leading to the carbonization process of corn straw being more complete. Consequently, the proportion of the C element rose with extended residence time, whereas the proportion of the H element decreased as the residence time increased.
]]>Authors: Siddharth Gautam David Cole
Selective adsorption using nanoporous materials is an efficient strategy for separating gas mixtures. In a nanoporous material, pores can exist in different shapes and can have different degrees of inter-connectivity. In recent studies, both pore connectivity and tortuosity have been found to affect the adsorption and dynamical properties of ethane and CO2 in silicalite differently. Here, using Monte Carlo simulations, we investigate if these two attributes can affect the selective adsorption of one component from a mixture of ethane and CO2 in silicalite. For this, the adsorption of an equimolar mixture of ethane and CO2 is simulated in 12 models of silicalite—SnZm (n, m = 0, 1, 2, 3 or 4; with n and m denoting, respectively, the fraction (out of 4) of straight and zigzag channels of silicalite that are available for adsorption)—differing in degrees of pore connectivity and tortuosity. The adsorption selectivity in this system is found to exhibit a reversal with the adsorption dominated by ethane at low pressures (below ~1 atm) and by CO2 at higher pressures (above ~10 atm). Pore connectivity is found to suppress the selective adsorption of CO2 at higher pressures and also shifts the selectivity reversal to higher pressures. The selectivity reversal results from a competition between the polarizability-affected adsorption at lower pressures and efficient packing at higher pressures. The efficient packing of CO2 is a compounded effect resulting from the larger effective pore volume available for CO2 due to its stronger interaction with the pore surface and smaller molecular volume. CO2 molecules show a preference to adsorb in non-tortuous pores, and this preference is found to be stronger in the presence of ethane. The effects of pore connectivity and tortuosity elucidated here should be applicable to a wide range of natural and engineered nanoporous materials, and this knowledge could be used to identify materials with better capability for separating and storing CO2 based on their pore attributes.
]]>Authors: Karthik Rathinam Volker Mauer Christian Bläker Christoph Pasel Lucas Landwehrkamp Dieter Bathen Stefan Panglisch
Increasing environmental concerns, stricter legal requirements, and a wide range of industrial applications have led to growing demand for activated carbon worldwide. The energy-intensive production of fresh activated carbon causes significant CO2 emissions and contributes to global competition for renewable carbon-based raw materials. Although (thermal) reactivation of spent activated carbon can drastically reduce the demand for fresh material, the reactivation process itself is still mostly based on experience and empirical knowledge locked into activated carbon companies. Despite the vast number of papers published in the field, practically relevant, systematic, and quantitative knowledge on the thermal reactivation process is barely available. This paper presents a simple and robust methodology for the development of a predictive model for the production of reactivated carbon with a defined product quality under energetically optimized conditions. An exhausted activated carbon sample was subjected to 26 reactivation experiments in a specially designed laboratory rotary kiln, whereas the experiments were planned and evaluated with statistical design of experiments. The influence of the reactivation conditions (heating rate, heating time, H2O/N2 volume ratio, and CO2/N2 volume ratio) on the specific surface area, energy consumption, yield, and adsorption capacity for diatrizoic acid were evaluated. The BET surface of the reactivated carbons ranged between 590 m2/g and 769 m2/g, whereas the respective fresh carbon had a BET surface of 843 m2/g. The adsorption capacity for diatrizoic acid measured as the maximum solid phase concentration qm derived from the Langmuir equation varied between 24.4 g/kg and 69.7 g/kg (fresh carbon: 59.6 g/kg). It was possible to describe the dependency of the quality criteria on different reactivation parameters using mathematical expressions, whereas the response surface methodology with nonlinear regression was applied to build the models. A reactivation experiment under statistically optimized conditions resulted in energy savings up to 65%, whereas the properties of the reactivated sample were close to the predicted values.
]]>Authors: Sang Jin Kim Seung-Jae Ha Jea Uk Lee Young-Pyo Jeon Jin-Yong Hong
For high-efficiency and high-stability lithium ion batteries, a silicon oxide-based carbon composite has been developed as an anode material. To minimize structural defects (cracking and pulverization) due to volumetric contraction/expansion during charge/discharge, silicon oxide (SiOx) is adopted. A pitch—a carbon precursor—is introduced to the surface of SiOx using the mechanofusion method. The introduced pitch precursor can be readily transformed into a carbon layer through stabilization and carbonization processes, resulting in SiOx@C. This carbon layer plays a crucial role in buffering the volume expansion of SiOx during lithiation/delithiation processes, enhancing electrical conductivity, and preventing direct contact with the electrolyte. In order to improve the capacity and cycle stability of SiOx, the electrochemical performances of SiOx@C composites are comparatively analyzed according to the mixing ratio of SiOx and pitch, as well as the loading amount in the anode material. Compared to pristine SiOx, the SiOx@C composite prepared through the optimization of the experimental conditions exhibits approximately 1.6 and 1.8 times higher discharge capacity and initial coulombic efficiency, respectively. In addition, it shows excellent capacity retention and cycle stability, even after more than 300 charge and discharge tests.
]]>Authors: Pengda Li Qiantao Lei Heyao Zhang Mingbo Qi Jinliang Song Pengfei Lian Jinxing Cheng Qingbo Wang Zhongfeng Tang Zhanjun Liu
The economics and safety of reactors can be affected by the diffusion of fission products into graphite. Xenon (Xe) fission products diffusing into graphite is the most critical neutron absorber and poison that can slow down or stop the chain reaction. The transport parameters for inhibiting the xenon diffusion in graphite are therefore an important scientific problem. Self-sintered nanopore-isotropic (~40 nm) graphite (SSNG) derived from green pitch coke can decrease Xe diffusion into graphite. In this study, the surface morphology and microstructural evolution in graphite before and after irradiation, as well as after annealing, were studied with different characterization methods. A method for the measurement of diffusion coefficients of fission products’ diffusion in graphite using Rutherford backscattering spectrometry (RBS) was also reported. The SSNG substrates were implanted with Xe at a dose of 4.8 × 1015 ions/cm2 and energy of 7 MeV. The RT-implanted samples were annealed in a vacuum at 650 °C for 9 h. The implanted and annealed samples were characterized using RBS. The diffusion coefficient D (Xe, 650 °C) was 6.49 × 10−20 m2/s. The results indicate SSNG’s excellent ability to inhibit Xe diffusion and are significant for designing and evaluating the safety of nuclear reactors.
]]>Authors: Sirine Zallouz Bénédicte Réty Jean-Marc Le Meins Mame Youssou Ndiaye Philippe Fioux Camélia Matei Ghimbeu
Although transition metal sulfides have prodigious potential for use as electrode materials because of their low electronegativities, their large volume changes inhibit broad application. Moreover, there is only limited knowledge of the ageing processes of these materials at the nanoscale. Herein, nano-C/FeS2 materials were prepared via one-pot syntheses from green biodegradable carbon precursors, followed by activation and sulfidation. The increased activation/sulfidation time led to an increase in the size of the nanoparticles (7 to 17 nm) and their aggregation, as well as in an increase in the specific surface area. The materials were then used as electrodes in 2-electrode symmetric supercapacitors with 2 M KOH. The activation process resulted in improved capacitance (60 F g−1 at 0.1 A g−1) and rate capability (36%) depending on the composite porosity, conductivity, and size of the FeS2 particles. The ageing of the FeS2 nanoparticles was investigated under air, and a progressive transformation of the nano-FeS2 into hydrated iron hydroxy sulfate with a significant morphological modification was observed, resulting in drastic decreases in the capacitance (70%) and retention. In contrast, the ageing of nano-FeS2 during cycling led to the formation of a supplementary iron oxyhydroxide phase, which contributed to the enhanced capacitance (57%) and long-term cycling (132% up to 10,000 cycles) of the device.
]]>Authors: Niki Loura Eleni Gkartzou Aikaterini-Flora Trompeta Georgios Konstantopoulos Panagiotis A. Klonos Apostolos Kyritsis Costas A. Charitidis
In the present study, a series of carbon-based nanocomposites based on recycled thermoplastic polyurethane (TPU) matrix and MWCNT fillers synthesized in a laboratory environment were prepared at various loadings and assessed in terms of their functional thermal, dielectric, and rheological properties, as well as their ohmic heating capability, for self-healing applications in extrusion-based 3D printing technologies. The synthesis of nanomaterials focused on the production of two different types of carbon nanotubes (CNTs) via the chemical vapor deposition (CVD) method. A comparative assessment and benchmarking were conducted with nanocomposite filaments obtained from commercial nanomaterials and masterbatches with MWCNTs. For all the polymer nanocomposites, samples were prepared at additive contents up to 15 wt.% and filament feedstock was produced via the melt-extrusion process for 3D printing; these were previously characterized by rheological tests. The measurements of thermal and electrical conductivity resulted in a selected composition with promising ohmic heating capability. As a preliminary assessment of the self-healing ability of the above samples, artificial cracks were introduced on the surface of the samples and SEM analysis took place at the crack location before and after applying voltage as a measure of the effectiveness of the material remelting due to the Joule effect. Results indicate a promising material response with a partial restoration of artificial cracks.
]]>Authors: José Moreira de Sousa Wjefferson Henrique da Silva Brandão Weverson Lucas Aguiar Paula Silva Luiz Antônio Ribeiro Júnior Douglas Soares Galvão Marcelo Lopes Pereira Júnior
A novel 2D carbon allotrope, pentagraphyne (PG-yne), was introduced in a recent theoretical study. This unique structure is derived from pentagraphene by incorporating acetylenic linkages between sp3 and sp2 hybridized carbon atoms. Given its intriguing electronic and structural properties, it is imperative to investigate the mechanical characteristics and thermal responses of PG-yne in both monolayer and nanotube configurations, which encompass different chiralities and diameters. We conducted fully atomistic reactive molecular dynamics (MD) simulations employing the ReaxFF potential to address these aspects. Our findings reveal that Young’s modulus of PG-yne monolayers stands at approximately 51 GPa at room temperature. In contrast, for the studied nanotubes, regardless of their chirality, it hovers around 45 GPa. Furthermore, our observations indicate that PG-yne-based systems feature an extensive and relatively flat plastic region before reaching the point of total fracture, irrespective of their topology. Regarding their thermal properties, we identified a melting point at approximately 3600 K, accompanied by a phase transition around 1100 K.
]]>Authors: Chhabi Lal Gnawali Lok Kumar Shrestha Jonathan P. Hill Renzhi Ma Katsuhiko Ariga Mandira Pradhananga Adhikari Rinita Rajbhandari Bhadra P. Pokharel
High-surface-area porous carbon materials with high porosity and well-defined pore structures are the preferred advanced supercapacitors electrode materials. Here, we report the electrochemical supercapacitive performance of novel high-porosity activated carbon materials prepared from biowaste Terminalia chebula (Harro) seed stones involving zinc chloride (ZnCl2) activation. Activation is achieved by mixing ZnCl2 with Harro seed powder (1:1 w/w) followed by carbonization at 400–700 °C under a nitrogen gas atmosphere. The amorphous carbon materials obtained exhibit excellent performance as electrical double-layer capacitor electrodes in aqueous electrolyte (1 M sulfuric acid) due to high specific surface areas (as high as 1382.6 m2 g−1) based on well-developed micropore and mesopore structures, and partial graphitic structure containing oxygenated surface functional groups. An electrode prepared using material having the optimal surface textural properties achieved a large specific capacitance of 328.6 F g−1 at 1 A g−1 in a three-electrode cell setup. The electrode achieved a good capacitance retention of 44.7% at a high 50 A g−1 current density and outstanding cycling performance of 98.2% even following 10,000 successive charge/discharge cycles. Electrochemical data indicate the significant potential of Terminalia chebula seed-derived porous carbons as high-performance electrode materials for high-energy-storage supercapacitor applications.
]]>Authors: Xiaoyan Wang Eng Gee Lim Kai Hoettges Pengfei Song
Flexible and wearable electronics have attracted significant attention for their potential applications in wearable human health monitoring, care systems, and various industrial sectors. The exploration of wearable strain sensors in diverse application scenarios is a global issue, shaping the future of our intelligent community. However, current state-of-the-art strain sensors still encounter challenges, such as susceptibility to interference under humid conditions and vulnerability to chemical and mechanical fragility. Carbon materials offer a promising solution due to their unique advantages, including excellent electrical conductivity, intrinsic and structural flexibility, lightweight nature, high chemical and thermal stability, ease of chemical functionalization, and potential for mass production. Carbon-based materials, such as carbon nanotubes, graphene, and nanodiamond, have been introduced as strain sensors with mechanical and chemical robustness, as well as water repellency functionality. This review reviewed the ability of carbon nanotubes-, graphene-, and nanodiamond-based strain sensors to withstand extreme conditions, their sensitivity, durability, response time, and diverse applications, including strain/pressure sensors, temperature/humidity sensors, and power devices. The discussion highlights the promising features and potential advantages offered by these carbon materials in strain sensing applications. Additionally, this review outlines the existing challenges in the field and identifies future opportunities for further advancement and innovation.
]]>Authors: Yi-Chun Chen Xin-Yu Jiang Bui Xuan Thanh Jia-Yin Lin Haitao Wang Chao-Wei Huang Hongta Yang Afshin Ebrahimi Sanya Sirivithayapakorn Kun-Yi (Andrew) Lin
As heterogeneous catalysis is a practical method for activating Oxone, the immobilization of transition metals (e.g., Co, Fe) on carbonaceous supports is a promising platform. Thus, this study attempts to develop a carbon-supported metallic catalyst by growing Co/Fe on carbon foam (CF) via adopting melamine foam as a readily available template which could be transferred to nitrogen-doped CF with marcoporous structures. Specifically, a unique adornment of Co/Fe species on this CF is facilely fabricated through a complexation of Co/Fe with a plant extract, tannic acid, on melamine foam, followed by carbonization to produce nano-needle-like Co/Fe on N-doped CF, forming a magnetic CF (MCF). This resultant MCF exhibits a much higher surface area of 54.6 m2/g than CF (9.5 m2/g), and possesses a much larger specific capacitance of 9.7 F/g, than that of CF as 4.0 F/g. These superior features of MCF enable it to accelerate Oxone activation in order to degrade an emerging contaminant, bis(4-hydroxyphenyl)methanone (BHPM). Furthermore, MCF + Oxone exhibits a lower activation energy as 18.6 kJ/mol for BHPM elimination and retains its effectiveness in eliminating BHPM over multiple rounds. More importantly, the CF is also prepared and directly compared with the MCF to study the composition-structure-property relationship to provide valuable insights for further understanding of catalytic behaviors, surficial characteristics, and application of such a functional carbon material.
]]>Authors: Christoph W. Thurner Leander Haug Daniel Winkler Christoph Griesser Matthias Leitner Toni Moser Daniel Werner Marco Thaler Lucas A. Scheibel Thomas Götsch Emilia Carbonio Julia Kunze-Liebhäuser Engelbert Portenkirchner Simon Penner Bernhard Klötzer
For the direct reduction of CO2 and H2O in solid oxide electrolysis cells (SOECs) with cermet electrodes toward methane, a fundamental understanding of the role of elemental carbon as a key intermediate within the reaction pathway is of eminent interest. The present synchrotron-based in situ near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) study shows that alloying of Ni/yttria-stabilized-zirconia (YSZ) cermet electrodes with Cu can be used to control the electrochemical accumulation of interfacial carbon and to optimize its reactivity toward CO2. In the presence of syngas, sufficiently high cathodic potentials induce excess methane on the studied Ni/yttria-stabilized-zirconia (YSZ)-, NiCu/YSZ- and Pt/gadolinium-doped-ceria (GDC) cermet systems. The hydrogenation of carbon, resulting from CO activation at the triple-phase boundary of Pt/GDC, is most efficient.
]]>Authors: Nemanja Gavrilov Stefan Breitenbach Christoph Unterweger Christian Fürst Igor A. Pašti
Understanding the properties and behavior of carbon materials is of paramount importance in the pursuit of sustainable energy solutions and technological advancements. As versatile and abundant resources, carbon materials play a central role in various energy conversion and storage applications, making them essential components in the transition toward a greener and more efficient future. This study explores the impact of diammonium hydrogen phosphate (DAHP) impregnation on activated carbon fibers (ACFs) for efficient energy storage and conversion applications. The viscose fibers were impregnated with varying DAHP concentrations, followed by carbonization and activation processes. The capacitance measurements were conducted in 6 mol dm−3 KOH, 0.5 mol dm−3 H2SO4, and 2 mol dm−3 KNO3 solutions, while the oxygen reduction reaction (ORR) measurements were performed in O2-saturated 0.1 mol dm−3 KOH solution. We find that the presented materials display specific capacitances up to 160 F g−1 when the DAHP concentration is in the range of 1.0 to 2.5%. Moreover, for the samples with lower DAHP concentrations, highly selective O2 reduction to peroxide was achieved while maintaining low ORR onset potentials. Thus, by impregnating viscose fibers with DAHP, it is possible to tune their electrochemical properties while increasing the yield, enabling the more sustainable and energy-efficient synthesis of advanced materials for energy conversion applications.
]]>Authors: Nina K. Plugotarenko Sergey P. Novikov Tatiana N. Myasoedova Tatiana S. Mikhailova
The low selectivity of materials to gases of a similar nature may limit their use as sensors. Knowledge of the adsorption kinetic characteristics of each gas on the surface of the material may enable the ability to identify them. In this work, copper-containing silicon–carbon films were formed using electrochemical deposition on the Al2O3 substrate with interdigitated Cr/Cu/Cr electrodes. These films showed good adsorption characteristics with several different gases. The adsorption kinetics of nitrogen dioxide, sulfur dioxide, and carbon monoxide on the film surface were investigated by the change in the resistivity of the material. Pseudo-first-order and pseudo-second-order kinetics, Elovich, Ritchie, and Webber intraparticle diffusion models were applied. It was found that the largest approximation factor and the lowest Root-Mean-Square Error and Mean Bias Error for all three gases were for the Elovich model. The advantages of silicon–carbon copper-containing films for gas sensor applications were shown. An algorithm for gas recognition was proposed based on the dependence of the change in the resistivity of the material under stepwise gas exposure. It was found that parameters such as the values of the extrema of the first and second derivatives of the R vs. t dependence during adsorption and the slope of R vs. t dependence in the Elovich coordinates are responsible for gas identification among several one-nature gases.
]]>Authors: Tamara Lazarević-Pašti Ana Jocić Vedran Milanković Tamara Tasić Katarina Batalović Stefan Breitenbach Christoph Unterweger Christian Fürst Igor A. Pašti
In light of the escalating environmental concerns regarding pesticide accumulation, it is imperative to devise efficient strategies for their removal. Among the various options, activated carbons have emerged as promising candidates for adsorptive pesticide removal due to their many advantages, such as large surface area, well-developed porosity, and cost-effectiveness. However, the intricate relationship between the properties of these materials and their performance in pesticide adsorption remains largely unexplored. This study primarily focuses on examining the adsorption kinetics of three organophosphate pesticides: dimethoate, malathion (aliphatic), and chlorpyrifos (aromatic), using a range of cellulose-based activated carbon fibers with diverse specific surface areas, pore size distributions, and elemental compositions. By employing sophisticated data analysis tools, principal component analysis, and semi-empirical quantum chemical calculations, this study uncovers the importance of these distinct properties in efficiently removing structurally diverse pesticides. The results of the adsorption experiments suggested that these processes can be described using a pseudo-second-order kinetic model, which is confirmed via multiple linear regression. The obtained data suggest that the most effective carbon material for pesticide removal should have a pore diameter of approximately 4 nm, low oxygen content, a unimodal pore size distribution, and a high presence of sp2 domains. The insights from this research have the potential to guide the development of improved adsorbents and facilitate the rational selection of adsorbents tailored to specific pollutants based on their physicochemical properties and the pollutants’ chemical structure. By shedding light on the vital connection between adsorbent properties and performance, our findings significantly advance sustainable and effective pesticide removal, thereby fostering a cleaner and healthier environment.
]]>Authors: Jorge S. S. Neto Daniel K. K. Cavalcanti Luiz E. da Cunha Ferro Henrique F. M. de Queiroz Ricardo A. A. Aguiar Mariana D. Banea
The main objective of this research centered on investigating the effect of the addition of multi-walled carbon nanotubes (MWCNTs) on the mechanical and thermal properties of curauá-fiber-reinforced composites. The MWCNTs were added either to the fiber surface or into the resin matrix as the second reinforcing phase. The MWCNT-modified curauá fibers as well as raw fibers were characterized using a single-fiber tensile test, TGA, and FTIR analysis. Further, different composite samples, namely, pure curauá, (curauá + MWCNTs) + resin and curauá+ (resin + MWCNTs), were manufactured via compression molding and tested to determine their mechanical and thermal properties. Scanning electron microscopy (SEM) analysis was used to examine the surfaces of the tested fibers. It was found that the addition of MWCNTs to the curauá fibers resulted in positive effects (an enhancement in properties was found for the MWCNT-modified fibers and their composites). The addition of MWCNTs also increased the thermal stability of the natural fibers and composites.
]]>Authors: Han-Wei Chang Zong-Ying Tsai Jia-Jun Ye Kuo-Chuang Chiu Tzu-Yu Liu Yu-Chen Tsai
The well-interconnected ternary Ni–Co–O nanosheets were grown on silicon carbide microspheres/graphite composite (gra@SiC/Ni–Co–O) by optimizing the electrodeposition method. Silicon carbide microspheres/graphite composite (gra@SiC) serves as a conductive template for the growth of Ni–Co–O nanosheets to form a binder-free 3D well-designed hierarchical interconnected network between the Ni–Co–O nanosheets and SiC microspheres. The obtained gra@SiC/Ni–Co–O is proposed as a great capacitance performance for supercapacitors. Field emission scanning electron microscopy (FESEM), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy, and electrochemical analysis were employed to investigate the morphology and structural and electrochemical characteristics. The synergistic effects of EDLC (SiC microspheres) and pseudo-capacitance (Ni–Co–O nanosheets) can effectively improve the supercapacitive performance. It is also worth mentioning that after electrochemical testing, the redox reaction of Ni–Co–O nanosheets greatly promoted the faradic pseudo-capacitance contribution, and silicon carbide microspheres/graphite composite contributed to the formation of a 3D interconnected network, improving the cycling stability during the charging/discharging processes.
]]>Authors: Raúl Llamas-Unzueta Luis A. Ramírez-Montoya J. Angel Menéndez Miguel A. Montes-Morán
Novel customised carbon monoliths with a high specific surface area were synthesised by carbonisation plus activation of dehydrated whey powders, a biomass byproduct of the dairy industry. The whey powders were casted directly by pouring them into a desired mould. After a pseudo-sintering process promoted by the self-reaction of the whey components (mostly lactose and whey proteins) at moderate temperatures (ca. 250 °C), 3D porous carbons were obtained. The process did not require any binder or external overpressure to prepare the 3D porous carbons. Upon thermal activation with CO2 or chemical activation with H3PO4 and KOH, the shape of the monolithic structure was preserved after the development of a microporous network (SBET up to 2400 m2/g). Both thermal and chemical activation had little effect on the macroporosity of the monoliths. Activation of these 3D carbons had to be performed with care to avoid heterogeneous skin/core activation and/or overactivation. Highly porous monoliths (SBET of 980 m2/g; open porosity of 70%) with outstanding compressive strength (10 MPa) could be obtained by thermal activation (CO2) of whey monoliths at 850 °C for 1.5 h. Additionally, the use of whey as a precursor provided the carbon monolith with a relatively high nitrogen content (ca. 3 wt.%).
]]>Authors: Qiu Jin Ziye Zheng Yuxiao Feng Shuang Tian Zuoli He
Hexavalent chromium (Cr(VI)) compounds are considered to be occupational carcinogens, which can be transferred from the environment to the human body and pose a significant threat to human health. It is particularly urgent to explore a more efficient catalyst for removing Cr(VI) to comply with discharge standards. The addition of CNTs enables the separation and transfer of photogenerated charges. Thus, we synthesized a range of NiCo2S4 hybrid materials with different multi-walled carbon nanotube (MWCNTs) contents using a two-step hydrothermal method. The composites had significant advantages compared to pure NiCo2S4, such as an enhanced visible light absorption, increased specific surface area, high electron–hole pair separation, and fast electron transport. Thus, MWCNT addition enabled efficient photocatalytic performances in terms of reducing hexavalent chromium (Cr(VI)). Among all the composite samples, the MWCNT/NiCo2S4 with 0.050 g of MWCNTs achieved the highest efficiency in reducing Cr(VI) under light irradiation, which showed a removal rate close to 100% within 40 min. Such CNT-based composite photocatalysts could be used to reduce the highly toxic Cr(VI) in environmental applications.
]]>Authors: Anna M. Ozerova Elena S. Tayban Inna L. Lipatnikova Arina R. Potylitsyna Yury I. Bauman Igor P. Prosvirin Yury V. Shubin Aleksey A. Vedyagin Ilya V. Mishakov Olga V. Netskina
In this study, carbon nanofibers were synthesized by the catalytic pyrolysis of trichloroethylene (CNF-Cl) and its mixture with acetonitrile (CNF-Cl-N). The addition of acetonitrile resulted in the incorporation of nitrogen in the CNF (0.33 at%), the removal of chlorine, an increase in oxygen-containing functional groups on the surface (from 1.6 to 3.6 at%), and an increase in the volume of mesopores (from 0.35 to 0.41 cm3·g−1) and macropores (from 0.115 to 0.393 cm3·g−1). The study of 2,4-DCBA adsorption on both CNFs revealed that the adsorption capacity showed dependence with a maximum on the 2,4-DCBA concentration in the solution, which was attributed to the electrostatic interactions of adsorbate with adsorbent at various pHs. The adsorption forces were effective over distances greater than the size of the 2,4-DCBA molecule, indicating volume pore filling. The maximum adsorption capacity occurred at 0.7–1.2 mM and a pH of 3.4 ± 0.1. CNF-Cl-N exhibited lower 2,4-DCBA adsorption than CNF-Cl-N due to its lower specific surface area, lower micropore volume, and higher concentration of oxygen-containing groups on the surface. However, these differences were not significant, suggesting that CNFs produced from both chlorine-containing wastes and their mixtures with nitrogen-containing compounds can be effectively used for water treatment to remove 2,4-DCBA.
]]>Authors: Bhavya Joshi Ahmed M. E. Khalil Shaowei Zhang Fayyaz A. Memon
Pharmaceuticals have emerged as a new class of ecological pollutants and have majorly contributed to harmful effects on the environment and human health. The presence of these pharmaceuticals in wastewater treatment plants, ground, and seawater has been reported widely. Organic dyes and other organic contaminants which are being considered as emerging contaminants are now in the race among the top organic pollutants that need effective treatment. Removal of these contaminants via green adsorbents has become an essential requirement towards a green and cleaner environment. Herein, we report the efficacy of the novel greener porous graphene obtained via the near-green synthesis method as an adsorbent material for treating seven organic pollutants: Methyl orange, Methyl red, Rhodamine-B, Ciprofloxacin, Atenolol, Ibuprofen, and Carbamazepine. Batch tests were conducted to investigate the effect of adsorption time and varying adsorbent dosages. The obtained greener porous graphene showed fast kinetics, which was determined to be guided by pseudo second-order kinetics and the maximum pollutant removal efficiency (>80%) was seen at a high adsorbent dosage (2 mL injected from a 5 g/L solution). Furthermore, the nonlinear adsorption modeling confirmed that the greener porous graphene followed the Langmuir model for the dye rhodamine-B sorption and the Freundlich model for all the other six contaminants. This greener porous graphene can be considered an effective adsorbent for the removal of organic pollutants in wastewater.
]]>Authors: Julie Genoyer Emna Helal Giovanna Gutierrez Nima Moghimian Eric David Nicole R. Demarquette
The effectiveness of layered particles as processing aid agents in molten polystyrene was studied. Three graphene grades and two clays of different lateral size were selected for this purpose. The morphologies of the composites were observed using scanning electron microscopy. Steady shear measurements were carried out and the Carreau–Yasuda model with yield stress was applied to the experimental results. A decrease in viscosity was observed at 2 wt.% of particle content for almost all composites. The most efficient particle for reducing viscosity was found to be graphene in a loose agglomerated configuration. Graphene and clay particles with similar dispersion states had a similar effect on the viscosity, inducing a decrease by 29% and 22%, respectively, suggesting comparable efficiency as processing aid agents. The observed decrease in viscosity is attributed to the phenomenon of superlubricity, which is a lubricating mechanism that is closely linked to the atomic structure of the particles.
]]>Authors: Jiajun Dai Shilpa Yadav Beate Paulus
Graphene has gained significant attention since its discovery in 2004, and the modification of few-layer graphene provides a platform to tailor its physical and electronic properties. In this study, we employed unrestricted density functional theory (DFT) with the PBE+U functional to investigate the electronic and magnetic properties of FeCl3-intercalated bilayer graphene (BLG). Both in BLG and stage-2 intercalated graphite, a distinct localization of electrons on a specific Fe atom is evident, gaining approximately 0.245 electrons evaluated with Bader analysis, while the holes are delocalized within the graphene layers. This results in p-doped graphene, characterized by a shift of the Dirac cone by 0.74 eV for BLG and 0.70 eV for stage-2 intercalated graphite. Ferromagnetic ordering is observed within the plane of FeCl3-intercalated BLG, whereas the FeCl3 layers exhibit antiferromagnetic coupling in stage-2 intercalated graphite. The ferromagnetic nature and electronic structure of the FeCl3-intercalated BLG is retained under pressure.
]]>Authors: Ziyi Wan Ping Tang Luwei Dai Yao Yang Lu Li Jun Liu Min Yang Guowei Deng
A reasonable design of nickel-based catalysts is key to efficient and sustainable energy conversion. For electrocatalytic materials in alkaline electrolytes, however, atomic-level control of the active sites is essential. Moreover, the well-defined surface structure contributes to a deeper understanding of the catalytic mechanism. Here, we report the loading of defective nickel–cobalt layered double hydroxide nanosheets (Ni2Co-LDH@C) after carbonization of silk. Under the precise regulation of the local coordination environment of the catalytic active site and the presence of defects, Ni2Co-LDH@C can provide an ultra-low overpotential of 164.8 mV for hydrogen evolution reactions (HERs) at 10 mA cm−2, exceeding that of commercial Pt/C catalysts. Density functional theory calculations show that Ni2Co-LDH@C optimizes the adsorption energy of the intermediate and promotes the O-O coupling of the active site in the oxygen evolution reaction. When using Ni2Co-LDH@Cs as cathodes and anodes to achieve overall water splitting, a low voltage of 1.63 V is required to achieve a current density of 10 mA cm−2. As an ideal model, Ni2Co-LDH@C has excellent water splitting properties and has the potential to develop water–alkali electrocatalysts.
]]>Authors: Vitalii Vashchynskyi Olena Okhay Tetiana Boychuk
The aim of this work is to study the properties of carbon materials prepared from apricot stones by carbonization at 300–900 °C and chemical activation by KOH with different ratios between components. It was found that increasing the carbonization temperature to 800–900 °C leads to the degradation of narrow micropores and the carbon matrix. The adsorbent materials were characterized with FTIR and SEM, and a specific surface area was calculated. Moreover, additional activation by HNO3 and annealing at 450 °C led to an increase in surface area up to 1300 m2/g. The obtained N-enriched sorbents show adsorption activities of 190–235 mg/g for methylene blue and 210–260 mg/g for methyl orange. The results of this study can be useful for future scale-up using the apricot material as a low-cost adsorbent for the removal of dyes in environmental remediation production.
]]>Authors: Milica S. Ritopečki Natalia V. Skorodumova Ana S. Dobrota Igor A. Pašti
Graphene is thought to be a promising material for many applications. However, pristine graphene is not suitable for most electrochemical devices, where defect engineering is crucial for its performance. We demonstrate how the boron doping of graphene can alter its reactivity, electrical conductivity and potential application for sodium and aluminum storage, with an emphasis on novel metal-ion batteries. Using Density Functional Theory calculations, we investigate both the influence of boron concentration and the oxidation of the material on the mentioned properties. It is demonstrated that the presence of boron in graphene increases its reactivity towards atomic hydrogen and oxygen-containing species; in other words, it makes B-doped graphene more prone to oxidation. Additionally, the presence of these surface functional groups significantly alters the type and strength of the interaction of Na and Al with the given materials. Boron-doping and the oxidation of graphene is found to increase the Na storage capacity of graphene by a factor of up to four, and the calculated sodiation potentials indicate the possibility of using these materials as electrode materials in high-voltage Na-ion batteries.
]]>Authors: Wenbei Bo Hongtao Zhang Guocheng Yin Liangzhu Zhang Jieqiong Qin
Among typical energy storage devices, supercapacitors play a predominant role in industry and our life owing to their rapid charge/discharge rate, superior lifespan, high power density, low cost, and outstanding safety. However, their low energy density has severely hindered their further development. For active electrode materials, graphene-based mesoporous nanosheets (GMNs) can combine the advantages from graphene and mesoporous materials, which can be applied to significantly enhance the energy density of supercapacitors. Here, we review the recent advances in GMNs for supercapacitors, focusing on in-plane mesoporous graphene and sandwich-like graphene-based heterostructures. Firstly, the synthesis of in-plane mesoporous graphene with ordered and disordered mesopores for supercapacitors is introduced. Secondly, sandwich-like graphene-based heterostructures are classified into mesoporous carbon/graphene, mesoporous heteroatom-doped carbon/graphene, mesoporous conducting polymer/graphene, and mesoporous metal oxide/graphene, and their applications in supercapacitors are discussed in detail. Finally, the challenges and opportunities of GMNs for high-performance supercapacitors are proposed.
]]>Authors: Ildikó Fekete-Kertész Krisztina László Mónika Molnár
Even though graphene-family materials (GFMs) hold great promise for various applications, there are still significant knowledge gaps in ecotoxicology and environmental risk assessment associated with their potential environmental impacts. Here, we provide a critical perspective on published ecotoxicity studies of GFMs based on meticulous bibliometric research. Based on the results of our review paper, in order to fill in the current critical knowledge gaps, the following issues are recommended for consideration: performing more studies on GFMs’ effects at environmentally relevant concentrations and more field and laboratory studies with marine and terrestrial organisms. It is also recommended to assess the ecotoxicity of GFMs in more environmentally relevant conditions, such as in trophic chain transfer studies and by multispecies exposure in micro- or mesocosms, as well as gaining insights into the interactive effects between GFMs and environmental pollutants. It was also revealed that despite their widespread detection in different environmental compartments the potential impacts of GFMs in complex test systems where hierarchical trophic organisation or trophic transfer studies are significantly under-represented. One of the main causes was identified as the difficulties in the physicochemical characterisation of GFMs in complex terrestrial test systems or aquatic micro- and mesocosm studies containing a sediment phase. The lack of tools for adequate characterisation of GFMs in these complex test systems may discourage researchers from conducting experiments under environmentally relevant test conditions. In the coming years, fundamental research about these complex test systems will continue to better understand the mechanism behind GFM toxicity affecting organisms in different environmental compartments and to ensure their safe and sustainable use in the future.
]]>Authors: Iriana Garcia Guerra Tannaz Tayyarian Omar Rodríguez-Uicab Jandro L. Abot
The hierarchical structure and microscale dimensions of carbon nanotube yarns (CNTYs) make them great candidates for the development of integrated sensing applications. The change in the electrical resistance of CNTYs due to mechanical strain, known as piezoresistivity, is the principal mechanism in strain sensing using CNTYs. While the axial tensile properties of CNTYs have been studied widely, studies on the axial piezoresistive response of CNTYS under compression have been limited due to the complexities associated with the nature of the experiments involving subjecting a slender fiber to compression loading in its axial direction. In this study, the piezoresistive response of a single CNTY embedded into a polymeric resin (CNTY monofilament composite) was investigated under axial compression. The results suggest that the CNTY exhibits a strong piezoresistive response in the axial direction with sensitivity or gauge factor values in the order of 0.4–0.5 for CNTY monofilament composites. The piezoresistive response of the CNTY monofilament composites under compression was compared to that under tension and it was observed that the sensitivity appears to be slightly lower under compression. The potential change in sensitivity between the freestanding CNTY and the CNTY monofilament composite under compression is still unknown. Knowing the axial piezoresistive response of the CNTYs under both tension and compression will enable their use in sensing applications where the yarn undergoes compression including those in aerospace and marine structures, and civil or energy infrastructure.
]]>Authors: Hsin-Ya Chiu Chun-Pei Cho
MnO2/nitrogen-containing graphene (x-NGM) composites with varying contents of Mn were used as the electrode materials for flexible asymmetric solid-state supercapacitors. The MnO2 was a two-phase mixture of γ- and α-MnO2. The combination of nitrogen-containing graphene and MnO2 improved reversible Faraday reactions and charge transfer. However, excessive MnO2 reduced conductivity, hindering ion diffusion and charge transfer. Overloading the electrode with active materials also negatively affected conductivity. Both the mass loading and MnO2 content were crucial to electrochemical performance. x-NGM composites served as cathode materials, while graphene acted as the anode material. Operating by two charge storage mechanisms enabled a synergistic effect, resulting in better charge storage purposes. Among the supercapacitors, the 3-NGM1//G1 exhibited the highest conductivity, efficient charge transfer, and superior capacitive characteristics. It showed a superior specific capacitance of 579 F·g−1, leading to high energy density and power density. Flexible solid-state supercapacitors using x-NGM composites demonstrated good cycle stability, with a high capacitance retention rate of 86.7% after 2000 bending cycles.
]]>Authors: Yoxkin Estévez-Martínez Enrique Quiroga-González Erick Cuevas-Yañez Sergio Durón-Torres Daniel Alaníz-Lumbreras Elizabeth Chavira-Martínez Rubén Posada-Gómez Jeremias Bravo-Tapia Víctor Castaño-Meneses
This work reports on membranes of a combination of chitosan–starch with lithium-modified multiwall carbon nanotubes. One of the most important contributions of this article is the functionalization of the surface of multiwall carbon nanotubes by means of an accessible technique that allows for high grafting yields of lithium and their incorporation into a polymeric matrix. The natural compounds chitosan and starch were used as a support to embed the nanotubes, forming membranes with good mechanical stability. A thorough characterization via Raman, infrared and X-ray photoelectron spectroscopies, transmission and scanning electron microscopies and dynamic mechanical analysis is presented here, as well as electrochemical characterization. The composition, structure and mechanical stability of the membranes make them viable candidates to be used as anodes sustainable Li-ion batteries.
]]>Authors: Giuliano M. Laudone Katie L. Jones
Characterizing materials with low surface areas or with very small sample sizes requires innovative approaches beyond traditional N2 and Ar adsorption measurements. The measurement of Kr adsorption isotherms is often employed to serve this purpose, yet its potential remains limited by the lack of models for the interpretation of the experimental results in terms of pore size distribution. In this work, simulated adsorption isotherms of Kr onto graphite in slit-shaped pores are generated with a Grand Canonical Monte Carlo method. The pore size distributions of nuclear-grade graphite samples and activated carbon are modelled by fitting simulated isotherms to the experimental data. The resulting distributions are favourably compared with those generated by commercially available modelling packages, based on the use of N2 adsorption isotherms using GCMC and BJH methods. The new GCMC-Kr kernel developed in this study offers an alternative method for the evaluation of the distribution of pore sizes in nuclear graphite and other low surface area materials, which can be employed when N2 and Ar adsorption measurements cannot be carried out.
]]>Authors: Radik R. Shamilov Zufar M. Muzipov Dmitriy O. Sagdeev Kirill V. Kholin Alina F. Saifina Aidar T. Gubaidullin Yuriy G. Galyametdinov
Photocatalysts based on graphitic carbon nitride (g-C3N4) attracted considerable attention due to their efficiency in hydrogen production and decomposition of organic pollutants in aqueous solutions. In this work, a new approach to synthesis of g-C3N4-based heterostructures with improved photocatalytic properties was proposed. The properties of two different CdZnS/g-C3N4 and ZnIn2S4/g-C3N4 heterostructures synthesized and studied in the same conditions were compared. Pure g-C3N4 photocatalysts as well as CdZnS/g-C3N4 and ZnIn2S4/g-C3N4 heterostructures were synthesized using a one-pot method by calcining the mixture of the initial components. Photocatalytic properties of the synthesized substances were evaluated in a model reaction of rhodamine B decomposition induced by visible light. It was shown that ultrasonic treatment in the presence of a nonionic surfactant enhances the photocatalytic activity of g-C3N4 structures as a result of a higher photocatalyst dispersity. The electronic structures of the CdZnS/g-C3N4 and ZnIn2S4/g-C3N4 heterostructures were analyzed in detail. The photocatalytic activity of heterostructures was found to be 2–3-fold higher as compared with an unmodified g-C3N4 due to formation of a type II heterojunction and Z-scheme structures. Decomposition of rhodamine B occurred mostly via formation of active oxygen radicals by irradiation.
]]>Authors: Galina L. Klimchitskaya Vladimir M. Mostepanenko
The Casimir–Polder force between atoms or nanoparticles and graphene-coated dielectric substrates is investigated in the region of large separations. Graphene coating with any value of the energy gap and chemical potential is described in the framework of the Dirac model using the formalism of the polarization tensor. It is shown that the Casimir–Polder force from a graphene-coated substrate reaches the limit of large separations at approximately 5.6 μm distance between an atom or a nanoparticle and graphene coating independently of the values of the energy gap and chemical potential. According to our results, however, the classical limit, where the Casimir–Polder force no longer depends on the Planck constant and the speed of light, may be attained at much larger separations depending on the values of the energy gap and chemical potential. In addition, we have found a simple analytic expression for the Casimir–Polder force from a graphene-coated substrate at large separations and determined the region of its applicability. It is demonstrated that the asymptotic results for the large-separation Casimir–Polder force from a graphene-coated substrate are in better agreement with the results of numerical computations for the graphene sheets with larger chemical potential and smaller energy gap. Possible applications of the obtained results in nanotechnology and bioelectronics are discussed.
]]>Authors: Anton P. Koskin Yurii V. Larichev Sergey A. Stepanenko Yury V. Dubinin Artem B. Ayupov Andrey A. Saraev Evgeny A. Suprun Petr M. Yeletsky
In this work, the use of graphite-like carbon nitride (g-C3N4) with improved texture characteristics for the synthesis of supported palladium catalysts of dehydrogenation of nitrogen-containing heterocycles was studied. This process is key to the creation of liquid organic carrier technology (LOHC) using N-heterocycles as reversibly hydrogenated/dehydrogenated substrates. For the preparation of graphite-like carbon nitride supports with advanced textural characteristics, well-established technology of the melamine cyanurate complex carbonization and standard techniques of adsorption precipitation together with wet impregnation were used for the synthesis of Pd-containing systems. The activity of the synthesized catalysts was studied in decahydroquinoline dehydrogenation. The high weight content of extractable hydrogen (7.2 wt%) and the high extraction rate, respectively, make it possible to consider these substances as the most promising N-heterocyclic compounds for this technology. It was shown that an increase in the specific surface area of g-C3N4 allows for achieving a slightly lower but comparable fineness of palladium particles for the 1 wt% Pd/MCA-500 sample, compared to the standard 1 wt% Pd/C. In this case, the catalytic activity of 1 wt% Pd/MCA-500 in the dehydrogenation of both substrates exceeded the analogous parameter for catalysts supported by nitrogen-free supports. This regularity is presumably associated with the electron-donor effect of surface nitrogen, which favorably affects the dehydrogenation rate as well as the stability of catalytic systems.
]]>Authors: Oleg A. Streletskiy Ilya A. Zavidovskiy Islam F. Nuriahmetov Olesya Y. Nishchak Alexander V. Pavlikov Natalya F. Savchenko
Resistive sensing responses of the thin films obtained by dehydrohalogenation of polyvinylidene chloride (PVDC) and polyvinylidene chloride–polyvinyl chloride (PVDC-PVC) copolymer were investigated. The structure of the samples was studied by transmission electron microscopy, Fourier-transform infrared spectroscopy and Raman spectroscopy. The analyses demonstrate the formation of a porous structure based on polyyne–polyene chains. The formation of a foam-like oxidized sp-rich structure was observed for the samples obtained via the chemical treatment of the PVDC. However, a loose film with a developed structure and a lower fraction of sp-hybridized carbon was observed for KOH-treated PVDC-PVC. The resistive sensing responses of both of the dehydrohalogenated structures were measured for various concentrations of acetone, acetic acid, ammonia hydroxide, methanol, ethanol, benzene and water. The interplay between the efficiency of the dehydrohalogenation of the films, their structure and sensing selectivity is discussed.
]]>Authors: Ming-Bo Qi Peng-Fei Lian Peng-Da Li He-Yao Zhang Jin-Xing Cheng Qing-Bo Wang Zhong-Feng Tang T. J. Pan Jin-Liang Song Zhan-Jun Liu
The diffusion behavior of iodine in micro/nano-porous graphite under high-temperature conditions was studied using analysis methods such as Rutherford backscattering Spectrometry, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The results indicate that iodine diffusion leads to the Lattice Contractions in Microcrystals, a decrease in interlayer spacing, and a rise of defect density. And the reversal or repair of microstructure change was observed: the microcrystal size of the graphite increases, the interlayer spacing appears to return to the initial state, and the defect density decreases, upon diffusion of iodine out of iodine-loaded graphite. The comparative study comparing the iodine diffusion performance of nanoporous graphite (G400 and G450) between microporous graphite (G500), showed that nanoporous graphite exhibits a better barrier to the iodine diffusion. The study on the diffusion behavior of iodine in micro/nano-porous graphite holds substantial academic and engineering value for the screening, design, and performance optimization of nuclear graphite.
]]>Authors: Aleksandra Jeżo Grzegorz Kowaluk
Finishing coatings used in the wood-based composite industry play a key role in the final appearance of the finished product. However, the use of such coatings is not only for aesthetic purposes, but also to protect the product against surface damage and moisture or to minimize the emission of harmful substances. The latter is an extremely important factor in terms of safety for both the manufacturer and the user, which is why the emissivity test is one of the most important tests conducted in this case. Carbon-rich materials, such as those remaining from the extraction of birch bark, can fulfill the role of minimizing the emission of harmful substances. In this article, an attempt to create coatings in the form of a film by combining a biopolymer with suberinic acid residues (SARs) was made. Two types of biopolymers were used, polylactide (PLA) and polycaprolactone (PCL), in various polymer–SAR ratios. Suberinic acid as a residue is a raw material that can potentially contribute positively to the fixing of CO2 from the atmosphere, which creates the possibility for further use. As part of this study, the obtained coatings were tested in terms of scratch resistance, relative hardness, cold liquids, total volatile organic compounds (TVOCs), formaldehyde emission, surface absorption, etc. Differences between the polymers used and the effect of the SAR additive on selected surface properties were demonstrated. The addition of carbon-rich SAR significantly improves gas barrier properties of the PLA- and PCL-based surface finishing materials. The relative hardness and scratch resistance also increased with rising SAR content. However, the increasing content of SAR filler acts as a limiter in the depth of penetration of the deposited surface finishing materials onto the wood surface. It is possible to state that this innovative approach regarding (1) the utilization of biopolymers as a matrix, instead of conventional, crude oil-based resins, and (2) the incorporation of post-processed carbon-rich waste lignocellulosic materials to produce the surface finishing and/or protective films has been confirmed.
]]>Authors: Cristian E. Rodriguez Audrey F. Adcock Buta Singh Subhadra Yerra Yongan Tang Ya-Ping Sun Liju Yang
Carbon dots (CDots) are generally defined as small carbon nanoparticles (CNPs) with effective surface passivation, for which the classical synthesis is the functionalization of pre-existing CNPs with organic molecules. However, “dot” samples produced by “one-pot” thermal carbonization of organic precursors are also popular in the literature. These carbonization-produced samples may contain nano-carbon domains embedded in organic matters from the precursors that survived the thermal processing, which may be considered and denoted as “nano-carbon/organic hybrids”. Recent experimental evidence indicated that the two different kinds of dot samples are largely divergent in their photo-induced antibacterial functions. In this work, three representative carbonization-produced samples from the precursor of citric acid–oligomeric polyethylenimine mixture with processing conditions of 200 °C for 3 h (CS200), 330 °C for 6 h (CS330), and microwave heating (CSMT) were compared with the classically synthesized CDots on their photo-induced antiviral activities. The results suggest major divergences in the activities between the different samples. Interestingly, CSMT also exhibited significant differences between antibacterial and antiviral activities. The mechanistic origins of the divergences were explored, with the results of different antimicrobial activities among the hybrid samples rationalized in terms of the degree of carbonization in the sample production and the different sample structural and morphological characteristics.
]]>Authors: Manuel Zulla Vera Vierheilig Maximilian Koch Andreas Burkovski Matthias Karl Stefan Rosiwal
Boron-doped diamond (BDD) electrodes are well known for the in situ production of strong oxidants. These antimicrobial agents are produced directly from water without the need of storage or stabilization. An in situ production of reactive oxygen species (ROS) used as antimicrobial agents has also been used in recently developed medical applications. Although BDD electrodes also produce ROS during water electrolysis, only a few medical applications have appeared in the literature to date. This is probably due to the difficulties in the miniaturization of BDD electrodes, while maintaining a stable and efficient electrolytic process in order to obtain a clinical applicability. In this attempt, a cannula-based electrode design was achieved by insulating the anodic diamond layer from a cathodic cannula, using a second layer of non-conducting diamond. The undoped diamond (UDD) layer was successfully grown in a spotted pattern, resulting in a perfectly insulated yet still functional BDD layer, which can operate as a miniaturized flow reactor for medical applications. The spotted pattern was achieved by introducing a partial copper layer on top of the BDD layer, which was subsequently removed after growing the undoped diamond layer via etching. The initial analytical observations showed promising results for further chemical and microbial investigations.
]]>Authors: Sofya D. Afonnikova Yury I. Bauman Vladimir O. Stoyanovskii Mikhail N. Volochaev Ilya V. Mishakov Aleksey A. Vedyagin
The development of effective catalysts for the pyrolysis of light hydrocarbons with the production of carbon nanomaterials represents a relevant direction. In the present work, the influence of copper addition on performance of a self-dispersed Ni-catalyst and structural features of the obtained carbon nanofibers (CNFs) was studied. The precursors of Ni and Ni-Cu catalysts were prepared by activation of metal powders in a planetary mill. During contact with the C2H4/H2 reaction mixture, a rapid disintegration of the catalysts with the formation of active particles catalyzing the growth of CNFs has occurred. The kinetics of CNF accumulation during ethylene decomposition on Ni- and Ni-Cu catalysts was studied. The effect of temperature on catalytic performance was explored and it was shown that introduction of copper promotes 1.5–2-fold increase in CNFs yield in the range of 525–600 °C; the maximum CNFs yield (100 g/gcat and above, for 30-min reaction) is reached on Ni-Cu-catalyst at 575–600 °C. A comparative analysis of the morphology and structure of CNF was carried out using electron microscopy methods. The growth mechanism of carbon filaments in the shape of “railway crossties” on large nickel crystals (d > 250 nm) was proposed. It was found that the addition of copper leads to a decrease in the bulk density of the carbon product from 40–60 to 25–30 g/L (at T = 550–600 °C). According to the low-temperature nitrogen adsorption data, specific surface area (SSA) of CNF samples (at T < 600 °C) lies in the range of 110–140 m2/g, regardless of the catalyst composition; at T = 600 °C the introduction of copper contributed to an increase in the specific surface of CNF by 100 m2/g.
]]>Authors: César R. de Oliveira Vinícius L. Rocha
It is shown that it is possible to adapt the quantum graph model of graphene to some types of nonequilateral graphynes considered in the literature; we also discuss the corresponding nanotubes. The proposed models are, in fact, effective models and are obtained through selected boundary conditions and an ad hoc prescription. We analytically recover some results from the literature, in particular, the presence of Dirac cones for α-, β- and (6,6,12)-graphynes; for γ-graphyne, our model presents a band gap (according to the literature), but only for a range of parameters, with a transition at a certain point with quadratic touch and then the presence of Dirac cones.
]]>Authors: Augusto Gonçalves Nobre Fabio Ramos Dias de Andrade Andres Fabian Salazar-Naranjo Josue Neroti Rigue Ricardo Barreto da Silva Silvio Roberto Farias Vlach Romulo Augusto Ando
The electrical properties of isolated graphene established precedents for studies of electrical superconducting materials at room temperature. After the discovery of stabilized graphene and graphite nanoplatelets in a geological context, the interest in characterizing the properties of these minerals arose. This work evaluates the electrical resistance evolution of mineral graphite and talc heterostructures under progressive metamorphism simulated in the laboratory. The experiments were conducted on an end-loaded piston-cylinder apparatus. This equipment allows for the application of equal pressure in all sample directions (lithostatic pressure) and heating, simulating geological phenomena. The behavior of two sets of mineral samples were compared: graphite and talc in billets and powder. Samples in billets were submitted to treatments at 400 °C and 4 kbar; 400 °C and 6 kbar; and 700 °C and 9 kbar. The powder samples were subjected to 700 °C and 9 kbar, with two ways of disposing the mineral powders (mixed and in adjacent contact) beyond 900 °C and 9 kbar (in adjacent contact). The results show that the samples in billets had lower electrical resistance when compared to the powder samples. The lowest electrical resistance was observed in the sample treated at 400 °C and 6 kbar, conditions that are consistent with metamorphic mineral assemblage observed in the field. Powdered samples showed better cleavage efficiency during the experiment, resulting in thinner flakes and even graphene, as pointed out by Raman spectroscopy. However, these flakes were not communicating, which resulted in high electrical resistance, due to the need for an electrical current to pass through the talc, resulting in a Joule effect. The maximum electrical resistance obtained in the experiment was obtained in the sample submitted to 900 °C, in which talc decomposed into other mineral phases that were even more electrically insulating. This work demonstrates that electrical resistance prospecting can be an efficient tool to identify potential target rocks with preserved mineral nanometric heterostructures that can form an important raw material for the nanotechnology industry.
]]>Authors: Aiden Rowley Yijing Stehle Luke Kilby Caleb Bashant
Reduced graphene oxide (rGO) has attracted attention as an active electrode material for flexible electrochemical devices due to its high electric conductivity and large surface area. Compared to other reduction processes, laser reduction is a precise, low-cost, and chemical-free process that is directly applied to graphene oxide (GO) membranes. This study aims to develop rGO through laser irradiation for application as electrodes in thin flexible electrochemical sensors. Laser irradiation parameters will be optimized to achieve reduction of a low oxygen to carbon (O/C) ratio and surface impedance. The influence of humidity on the impedance of rGO electrodes will be studied. The observed instability of the rGO electrode is related to incomplete reduction and oxygenated defects involved in reduction. Partially removed oxygenated functional groups not only influence the impedance of the electrode but make it sensitive to the humidity of the working environment. The result provides references for GO’s laser reduction optimization, demonstrates the potential of applying rGO as an electrode in sensing applications, but also reveals the limitation of applying the laser reduced rGO electrode in a non-constant humidity environment.
]]>Authors: Natália Garrote de Barros Abel Cardoso Gonzaga Neto Kleber Bitencourt Vaccioli Hugo Rafael Vallejo Angulo Leonardo Gondim de Andrade e Silva Samuel Marcio Toffoli Ticiane Sanches Valera
This paper presents a comparison of traditional thermal and chemical reduction methods with more recent ionizing radiation reduction via gamma rays and electron beams (e-beams). For GO, all synthesis protocols were adapted to increase production scale and are a contribution of this work. The typical Raman D-band of the GO was prominent (ID/IG ratio increased sixfold). When comparing the GO reduction techniques, dramatic differences in efficiency and GO particle characteristics were observed. Although thermal and chemical reduction are effective reduction methods, as shown through the use of FTIR spectroscopy and the C/O ratio from EDS chemical analysis, the thermal process renders great weight losses, whereas chemical processing may involve the use of hazardous chemical compounds. On the other hand, comparing the gamma rays and e-beam for 80 kGy, the Raman spectra and chemical analysis suggested that the e-beam caused a greater GO reduction: C/O ratio from EDS of 5.4 and 4.1, respectively. In addition to being fast and effective, ionizing radiation reduction processes allow easier control of the reduction degree by adjusting the radiation dose. When the dose increased from 40 to 80 kGy, the Raman spectra and EDS showed that the ID/IG and C/O ratios increased by 15 and 116%, respectively.
]]>Authors: Elisaveta Snezhkova Heinz Redl Johannes Grillari Marcin Osuchowski
(1) Background: Uncontrolled inflammation often contributes to life-threatening sepsis sequela such as multi-organ dysfunction syndrome (MODS), and is accompanied by abnormal levels of pathological and damage-associated molecular patterns (PAMPs & DAMPs) in biological fluids. Activated carbon or charcoal (AC) of new generation with ameliorated biocompatibility has spurred renewed interest in the regulation of these toxins’ levels in inflammation states. (2) Methods: We searched PubMed, Google Scholar, ScienceDirect, Researchgate, and other sources for the relevant literature from 1550 B.C. till 2022 A.C. (3) Results: Laboratory and clinical investigations demonstrate that activated carbon or charcoal (AC) mitigates inflammation in different pathological states when applied orally, per rectum, or in a hemoperfusion system. AC protects the microbiome and bone marrow, acts as an anti-inflammatory and anti-oxidant remedy, and recovers the plasmatic albumin structure. The mechanism of AC action is related to a non-selective (broad-range) or/and selective adsorption of PAMPs & DAMPs from biological fluids. A high-adsorptive capacity towards noxious substances and application of AC as early as possible seems paramount in inflammation treatment for preventing sepsis and/or multi-organ failure. (4) Conclusion: AC could be considered an adjunctive treatment for preventing sepsis and/or multi-organ failure.
]]>Authors: Irina Ceban (Ginsari) Tudor Lupascu Sergey Mikhalovsky Raisa Nastas
In this study, activated carbons derived from walnut shells (CA-N) and apple wood (CA-M) were used as adsorbents to remove cobalt(II) and strontium(II) ions from aqueous solutions. The novel materials were obtained using nitric acid (CA-Mox) and nitric acid/urea mixture (CA-Mox-u, CA-Nox-u) as oxidizing agents. The physical–chemical characteristics of activated carbons were determined from nitrogen sorption isotherms, SEM-EDX, FTIR, pH metric titrations, the Boehm titration method and elemental analysis. The results of batch experiments indicate that maximum adsorption can be achieved in broad pH ranges: 4–8 for Co(II) and 4–10 for Sr(II). The maximum adsorption capacities of Co(II) and Sr(II) on oxidized activated carbons at pH = 4 are: CA-Mox, 0.085 and 0.076 mmol/g; CA-Mox-u, 0.056 and 0.041 mmol/g; and CA-Nox-u, 0.041 and 0.034 mmol/g, respectively. The mathematical models (pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models, and Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin–Pyzhev isotherm models) were used to explain the adsorption kinetics, to study the adsorption mechanism and predict maximum adsorption capacity of the adsorbents. The adsorption mechanisms of toxic metal ions on activated carbons were proposed.
]]>Authors: Sonal Santosh Bagade Shashidhar Patel M. M. Malik Piyush K. Patel
This paper presents an intensive review covering all the versatile applications of graphene and its derivatives in solar photovoltaic technology. To understand the internal working mechanism for the attainment of highly efficient graphene-based solar cells, graphene’s parameters of control, namely its number of layers and doping concentration are thoroughly discussed. The popular graphene synthesis techniques are studied. A detailed review of various possible applications of utilizing graphene’s attractive properties in solar cell technology is conducted. This paper clearly mentions its applications as an efficient transparent conducting electrode, photoactive layer and Schottky junction formation. The paper also covers advancements in the 10 different types of solar cell technologies caused by the incorporation of graphene and its derivatives in solar cell architecture. Graphene-based solar cells are observed to outperform those solar cells with the same configuration but lacking the presence of graphene in them. Various roles that graphene efficiently performs in the individual type of solar cell technology are also explored. Moreover, bi-layer (and sometimes, tri-layer) graphene is shown to have the potential to fairly uplift the solar cell performance appreciably as well as impart maximum stability to solar cells as compared to multi-layered graphene. The current challenges concerning graphene-based solar cells along with the various strategies adopted to resolve the issues are also mentioned. Hence, graphene and its derivatives are demonstrated to provide a viable path towards light-weight, flexible, cost-friendly, eco-friendly, stable and highly efficient solar cell technology.
]]>Authors: Anastasia Nikologianni Alex Albans
As the world takes a more strategic approach to the climate crisis, carbon in its various forms has become a key factor in ascertaining the sustainability of the landscape. Landscape has been recognised as a resource and mechanism for addressing the role of carbon in the environment, with literature focused on the landscape’s carbon capacity as interconnected systems of land, soil, water and organic life. It has, however, largely neglected the crucial role of the cultural, social and historical aspects of the landscape, particularly at the level of design. This paper acknowledges and explores the complexity of landscape as a natural-cultural system with the consequent difficulties this poses in legislating, calculating and measuring carbon for global, national and local targets for low/zero carbon and carbon offsetting. The discussion takes place in the arena of landscape architecture at regional/city/local scales and the life-cycle of a project including its integration into its wider social, cultural and environmental setting. This paper develops the discourse in three major areas: first, by examining how the complexity of landscape is obscured in the context of carbon-measuring tools used in landscape architecture; secondly exploring one such tool in practice to demonstrate how site-specific design decisions can impact carbon levels; and third by proposing how an integrated understanding of landscape can be built into projects to embrace complexity and operationalise low carbon visions.
]]>Authors: Samantha K. Samaniego Andrade Alfréd Menyhárd Szilvia Klébert Miklós Mohai Balázs Nagy Krisztina László
S and N double-doped high surface area biomass-derived carbons were obtained from marine biomass-derived ι-carrageenan. Adding carbon nanoparticles (CNPs), namely graphene oxide (GO) or carbon nanotubes (CNTs), in the early stage of the synthesis leads to a modified porous texture and surface chemistry. The porous textures were characterized by N2 (−196.15 °C) and CO2 (0 °C) isotherms. The best GO- and CNT-added carbons had an apparent surface area of 1780 m2/g and 1170 m2/g, respectively, compared to 1070 m2/g for the CNP-free matrix. Analysis of the Raman spectra revealed that CNT was more efficient in introducing new defects than GO. Based on XPS, the carbon samples contain 2–4.5 at% nitrogen and 1.1 at% sulfur. The Dubinin–Radushkevich (DR) and Henry models were used to assess the strength of the interactions between various gases and the surface. The N2/H2 and CO2/CH4 selectivities were estimated with ideal adsorbed solution theory (IAST). While the CNPs, particularly GO, had a remarkable influence on the porous texture and affected the surface chemistry, their influence on the separation selectivity of these gases was more modest.
]]>Authors: Simeng Li Desarae Tasnady
Biochar, a sustainable solid material derived from biomass pyrolysis enriched in carbon, has emerged as a promising solution for soil carbon sequestration. This comprehensive review analyzes the current knowledge on biochar’s application in this context. It begins by examining biochar properties and production methods, highlighting its recalcitrant nature as a potential stable carbon sink. The influence of various feedstocks and pyrolysis conditions on various physicochemical properties of biochar and its soil carbon sequestration potential is explored. Mechanisms through which biochar enhances soil carbon sequestration are discussed, including its role as a physical barrier against carbon loss and its ability to promote stable soil aggregates and influence soil microorganisms. Challenges and limitations, such as variations in biochar properties and optimal application rates, are addressed, along with strategies for maximizing biochar effectiveness through amendments. The review concludes by emphasizing the importance of long-term field studies, standardized protocols, and economic assessments to support the widespread adoption of biochar for soil carbon sequestration and its potential in climate change mitigation.
]]>Authors: Denis Miroshnichenko Kateryna Shmeltser Maryna Kormer
The raw materials (coals different stages of metamorphism) and technological factors (period and temperature) of the coke-making that determine the carbon structure of blast furnace coke, and its physical and mechanical properties are analyzed. The change granulometric composition of the coke as a function of the coal batch properties is described in detail. The installation determines the possibility of influencing the carbon structure of coke, its granulometric composition in its production in order to increase the yields of the most valuable fractions, and improving its quality characteristics to achieve high-performance blast furnaces. Analysis of the results indicates that, with no changes in the coking conditions, the granulometric composition depends significantly on the ash content and packing density of the coal batch. Research has shown that the petrographic composition of the coal batch also affects the structure and size of the coke. The closest relationship is established between the magnitude of the fusinized components ΣFC and the output of the coke fractions 80–60 mm, 40–25 mm, and <25 mm. The method of mechanical treatment and stabilizing of blast furnace coke is proposed, which includes the improvement of the initial indexes of its quality M25, M10, and class >80 mm in continuous or periodically working open or closed industrial cylindrical oblique stabilizer drum.
]]>Authors: Hanna Bukovska Fernando García-Perez Natalia Brea Núñez Laura J. Bonales Andrés Velasco M. Ángeles Clavero Javier Martínez Alberto J. Quejido Isabel Rucandio M. Belén Gómez-Mancebo
Many of the graphene-based structures exhibit an adsorption capacity due to their high specific surface area (SSA) and micropore volume. This capacity makes them competent materials for applications in energy and environmental sectors where efficiency is highly dependent on these properties for applications, such as water decontamination, solar cells or energy storage. The aim of this work is to study graphene-related materials (GRM) for applications where a high SSA is a requirement, considering the ideal SSA of graphene ≅ 2600 m2g−1. For the synthesis of most of the GRMs, some oxidation method such as the Tour method is used to oxidize graphite to graphite oxide (GrO) as an initial step. Our work studies the optimization of this initial step to evaluate the best conditions to obtain GrO with the maximum possible SSA. The different parameters influencing the process have been evaluated and optimized by applying an experimental design (ED). The resulting materials have been characterized by Brunauer–Emmett–Teller (BET), elemental analysis (EA), X-ray diffraction (XRD) and Raman and scanning electron microscopy (SEM). The evaluation of the results shows a maximum SSA of GrO of 67.04 m2g−1 for a temperature of 60 °C, a time of 12 h, a H2O2 volume of 50 mL and 4 g of KMnO4.
]]>Authors: Galina L. Klimchitskaya Vladimir M. Mostepanenko
The Casimir–Polder force acting on atoms and nanoparticles spaced at large separations from real graphene sheets possessing some energy gaps and chemical potentials is investigated in the framework of the Lifshitz theory. The reflection coefficients expressed via the polarization tensor of graphene, found based on the first principles of thermal quantum field theory, are used. It is shown that for graphene the separation distances, starting from which the zero-frequency term of the Lifshitz formula contributes more than 99% of the total Casimir–Polder force, are less than the standard thermal length. According to our results, however, the classical limit for graphene, where the force becomes independent of the Planck constant, may be reached at much larger separations than the limit of the large separations determined by the zero-frequency term of the Lifshitz formula, depending on the values of the energy gap and chemical potential. The analytic asymptotic expressions for the zero-frequency term of the Lifshitz formula at large separations are derived. These asymptotic expressions agree up to 1% with the results of numerical computations starting from some separation distances that increase with increasing energy gaps and decrease with increasing chemical potentials. The possible applications of the obtained results are discussed.
]]>Authors: Fabio Peinetti Muhammad Yasir Patrizia Savi
This paper presents a radio-frequency (RF) antenna as a sensor to detect Horseradish peroxidase (HRP). At the core of the proposed approach is a graphene film deposited on a stub connected to an RF antenna. The graphene film is doctor bladed on the stub. The film is then properly chemically functionalized in order to detect the presence of Horseradish peroxidase (HRP). We validate the proof-of-concept operation of HRP concentration detection by measuring the frequency shift of the reflection coefficient of the antenna using very small concentration of HRP (0.03 mM to 0.6 mM).
]]>Authors: Sergey P. Lebedev Ilya A. Eliseyev Mikhail S. Dunaevskiy Ekaterina V. Gushchina Alexander A. Lebedev
A new technique for determining the point spread function, which is required for measuring the surface potential using Kelvin probe microscopy (KPM), is presented. The method involves using a silicon carbide substrate coated with single-layer and bilayer graphene as a test structure and obtaining KPM potential profiles in different directions on the surface. This makes it possible to determine the KPM point spread function, which can be used to perform deconvolution and accurately recover the surface potential.
]]>Authors: Fatemeh Mollaamin Majid Monajjemi
Bisphosphonate (BP) agents have attracted much attention for their precise therapy in some skeletal maladies demonstrated by enhancing osteoclast-mediated bone resorption. In this work, the use of CAM-B3LYP/6-311+G(d,p)/LANL2DZ to estimate the susceptibility of single-walled carbon nanotube (SWCNT) for adsorbing alendronate, ibandronate, neridronate, and pamidronate chelated to two metal cations of 2Mg2+, 2Ca2+, and 2Sr2+ through nuclear magnetic resonance and thermodynamic parameters has been accomplished. For most biological medications, oral bioavailability is too low to reach a therapeutic level, and advanced delivery systems such as formulations including permeation enhancers or enzyme inhibitors, lipid-based nanocarriers, and microneedles will likely increase the oral bioavailability of these medications properly. Therefore, the measurements have described that the eventuality of using SWCNT and BP agents becomes the norm in metal chelating of the drug delivery system, which has been selected through (alendronate, ibandronate, neridronate, pamidronate) → 2X (X = Mg2+/Ca2+/Sr2+) complexes. The NMR results of chelated alendronate, ibandronate, neridronate, and pamidronate complexes adsorbed onto (5,5) armchair SWCNT have remarked the location of active sites of tagged nitrogen (N), phosphorus (S), oxygen (O), and metal cations of magnesium (Mg2+), calcium (Ca2+), and strontium (Sr2+) in these molecules which replace the movement of the charge electron transfer in polar bisphosphonates (BPs) toward (5,5) armchair carbon nanotube (CNT). The thermodynamic results have exhibited that the substitution of 2Ca2+ cation by 2Sr2+ cation in the compound of the bioactive glasses can be efficient for treating vertebral complex fractures. However, the most fluctuation in the Gibbs free energy for BPs → 2Sr2+ has been observed at 300 K. This manuscript aimed to show that (5,5) armchair SWCNT can easily penetrate in the bone cells, delivering chelated BP–cations directly to the bone tissue. Drug delivery systems can improve the pharmacological profile, therapeutic profile, and efficacy of BP drugs and lower the occurrence of off-targets.
]]>Authors: Mariana A. Vieira Tainara L. G. Costa Gustavo R. Gonçalves Daniel F. Cipriano Miguel A. Schettino Elen L. da Silva Andrés Cuña Jair C. C. Freitas
The reduction of graphene oxide (GO) by means of thermal and/or chemical treatments leads to the production of reduced graphene oxide (rGO)—a material with improved electrical conductivity and considered a viable and low-cost alternative to pure graphene in several applications, including the production of supercapacitor electrodes. In the present work, GO was prepared by the oxidation of graphite recycled from spent Li-ion batteries using mixtures of sulfuric and phosphoric acids (with different H2SO4/H3PO4 ratios), leading to the production of materials with significant S and P contents. These materials were then thermally reduced, resulting in rGO papers that were investigated by solid-state 13C and 31P nuclear magnetic resonance, along with other methods. The electrochemical properties of the produced rGO papers were evaluated, including the recording of cyclic voltammetry and galvanostatic charge–discharge curves, besides electrochemical impedance spectroscopy analyses. The samples obtained by thermal reduction at 150 °C exhibited good rate capability at high current density and high capacitance retention after a large number of charge–discharge cycles. The results evidenced a strong relationship between the electrochemical properties of the produced materials and their chemical and structural features, especially for the samples containing both S and P elements. The methods described in this work represent, then, a facile and low-cost alternative for the production of rGO papers using graphite recycled from spent batteries, with promising applications as supercapacitor electrodes.
]]>Authors: Ravi Moreno Araujo Pinheiro Lima Glaydson Simões dos Reis Ulla Lassi Eder Claudio Lima Guilherme Luiz Dotto Helinando Pequeno de Oliveira
The synthesis of high-performance carbon-based materials from biomass residues for electrodes has been considered a challenge to achieve in supercapacitor-based production. In this work, activated biochar has been prepared as the active electrode material for supercapacitors (SCs), and an effective method has been explored to boost its capacitive performance by employing polypyrrole (PPy) as a biochar dopant. The results for physicochemical characterization data have demonstrated that PPy doping affects the biochar morphology, specific surface area, pore structure, and incorporation of surface functionalities on modified biochar. Biochar-PPy exhibited a surface area of 87 m2 g−1, while pristine biochar exhibited 1052 m2 g−1. The SCs were assembled employing two electrodes sandwiched with PVA solid-state film electrolyte as a separator. The device was characterized by standard electrochemical assays that indicated an improvement of 34% in areal capacitance. The wood electrodes delivered high areal capacitances of 282 and 370 mF cm−2 at 5 mA cm−2, for pure biochar and biochar doped with PPy, respectively, with typical retention in the capacitive response of 72% at the end of 1000 cycles of operation of the supercapacitor at high current density, indicating that biochar-PPy-based electrode devices exhibited a higher energy density when compared to pure biochar devices.
]]>Authors: Olga Goncharova Georgy Matyshak Maria Timofeeva Stanislav Chuvanov Matvey Tarkhov Anna Isaeva
The landscapes in the discontinuous permafrost area of Western Siberia are unique objects for assessing the direct and indirect impact of permafrost on greenhouse gas fluxes. The aim of this study was to identify the influence of permafrost on the CO2 emission at the landscape and local levels. The CO2 emission from the soil surface with the removed vegetation cover was measured by the closed chamber method, with simultaneous measurements of topsoil temperature and moisture and thawing depth in forest, palsa, and bog ecosystems in August 2022. The CO2 emissions from the soils of the forest ecosystems averaged 485 mg CO2 m−2 h−1 and was 3–3.5 times higher than those from the peat soils of the palsa mound and adjacent bog (on average, 150 mg CO2 m−2 h−1). The high CO2 emission in the forest was due to the mild soil temperature regime, high root biomass, and good water–air permeability of soils in the absence of permafrost. A considerable warming of bog soils, and the redistribution of CO2 between the elevated palsa and the bog depression with water flows above the permafrost table, equalized the values of CO2 emissions from the palsa and bog soils. Soil moisture was a significant factor of the spatial variability in the CO2 emission at all levels. The temperature affected the CO2 emission only at the sites with a shallow thawing depth.
]]>Authors: Silvia Izquierdo Nazaret Pacheco Carlos J. Durán-Valle Ignacio M. López-Coca
Carbonaceous materials are a highly appealing class of adsorbents, owing to their exceptional properties, such as high surface area and thermal and chemical stability. These materials have found successful applications in water purification. Sweet chestnut (Castanea sativa) cupules are disposed of as waste. Valorization of these residues is a step forward in terms of circular economy and sustainability. Meanwhile, per- and poly-fluoroalkyl substances (PFASs) pose significant concerns due to their persistence, bioaccumulation, and toxicity, emerging as contaminants of concern for human health and the environment. This study focuses on preparing carbonaceous material by hydrothermal carbonization from chestnut cupules, followed by their use as adsorbents for PFAS removal from polluted water. The cupule waste material was crushed, ground, sieved, and subjected to hydrothermal treatment at temperatures ranging from 180–200 °C to produce hydrothermal carbons. The adsorbents obtained were characterized by various techniques such as nitrogen adsorption isotherm, porosimetry, point of zero charge, Fourier-transform infrared, scanning electron microscopy, and thermal, elemental, and energy dispersive X-ray analyses. Surface area (SBET) values of 42.3–53.2 m2·g−1 were obtained; pHPZC ranged from 3.8 to 4.8. This study also determined the adsorption kinetics and isotherms for removing perfluorooctanoate-contaminated water. The equilibrium was established at 72 h and qe = 1029.47 mg·g−1. To summarize, this research successfully valorized a biomass residue by transforming it into hydrothermal carbon, which was then utilized as an adsorbent for water decontamination.
]]>Authors: Akshay Gharpure Randy L. Vander Wal Sarma Pisupati
This work evaluates the potential for obtaining graphitizable precursors from domestically available coal as a possible solution to the declining availability of high-quality precursors and projected rapid growth driven by demand for synthetic graphite in the US. The graphitizability of a coal-derived synthetic pitch (Synpitch) obtained by a novel solvent extraction process is compared with a commercially available petroleum pitch. The process outlined in this paper offers the advantages of lower temperature, pressure, and hydrogen addition requirement. An upgraded (higher H/C) aromatic pitch with low quinoline insoluble (QI) and ash content is obtained. The distinctions between the pitches have been characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, and thermogravimetric analysis/differential scanning calorimetry. The pitches have been graphitized at 2500 °C and characterized by X-ray diffraction and transmission electron microscopy for graphitic quality assessment. The Synpitch showed larger crystallites (by over 50%) and markedly better nanostructure compared to the commercial pitch used in this study. The structural differences between the pitches are highlighted here to explain the significantly better graphitic quality of the Synpitch.
]]>Authors: Andrey A. Khomich Roman Khmelnitskii Maria Kozlova Alexander V. Khomich Victor Ralchenko
We investigated the IR absorption spectra of CVD diamond damaged by fast neutrons (>0.1 MeV) with high fluences ranging from 1 × 1018 to 2 × 1019 cm−2 and annealed at temperatures of 200 °C to 1680 °C. After annealing above 1000 °C, the formation of “amber-centers” (ACs), associated with multivacancy clusters, is detected as deduced from the appearance of a strong absorption line at 4100 cm−1. Moreover, the concentration of the ACs in the irradiated diamond can be an order of magnitude higher than that observed previously in the darkest brown natural diamonds. A number of other absorption lines, including the H1b center at 4936 cm−1 (0.612 eV) and new lines at ~5700 cm−1 (0.706 eV) and 9320 cm−1 (1.155 eV) not reported before in the literature, are observed, and their intensity evolutions at annealing temperatures are documented. At the highest fluences, all the lines show reduced intensities and broadening and spectral shifts due to a very high defect concentration and partial amorphization. The obtained experimental data can be used for the analysis of defect generation, transformations and healing in irradiated synthetic and natural diamonds.
]]>Authors: Chensong Dong
A simple method for determining the effective elastic modulus of wavy single-wall carbon nanotubes (SWCNTs) is presented in this paper. The effective modulus of curved SWCNTs is derived using Castigliano’s theorem. The effect of curvature on the effective modulus is studied. This method is verified by finite element analysis (FEA). The distributions of effective moduli are studied by Monte Carlo simulation. The effective modulus of a general wavy SWCNT is derived by considering the SWCNT as a number of curved SWCNT sections.
]]>Authors: A. A. Ivlev
The global carbon cycle model is presented as a natural self-regulating machine that provides renewable biomass synthesis during evolution. The machine consists of two parts, geological and biosphere. Between the parts, there is an interaction. The geological part is controlled by the movement of lithosphere plates, which is under the guidance of gravitational forces from celestial bodies acting on the Earth. The movement of the lithosphere plates is divided into a phase of a relatively quick movement, occurring in the tectonically active state of the Earth’s crust, named the orogenic period, and a phase of a relatively slow movement, occurring in the phase of the tectonically quiet state of the crust, named geosynclinal period. In the orogenic period, the energy of moving plates’ collisions is sufficient to initiate sulfate reduction, proceeding in the subduction zone. This is the reaction where sedimentary organic matter is oxidized. Resultant CO2 is injected into “atmosphere—hydrosphere” system of the Earth. Its concentration achieves maximal values, whereas oxygen concentration drops to a minimum since it reacts with the reduced sulfur forms that evolve in the thermochemical sulfate reduction and due to binding with reduced forms of metals, coming to the Earth’s surface with volcanic exhalations. Carbon dioxide initiates photosynthesis and the associated biosphere events. In the geosynclinal period, the sulfate reduction ceases, and CO2 does not enter the system anymore, though photosynthesis in the biosphere proceeds in the regime of CO2 pool depletion. Under such conditions, the surface temperature on the Earth decreases, ending with glaciations. The successive depletion of the CO2 pool results in a regular sequence of climatic changes on the Earth. The ratio of CO2/O2 is the key environmental parameter in the orogenic cycle providing climatic changes. They consistently vary from hot and anaerobic in the orogenic period to glacial and aerobic by the end of the geosynclinal period. The climatic changes provide biotic turnover. Especially abrupt changes accompany the transition to a new orogenic cycle, resulting in mass extinction of organisms and the entry of huge masses of biogenic material into the sediment. This provided the conditions for the formation of rocks rich in organic matter (“black shales”). It is shown that the suggested model is supported by numerous geological and paleontological data evidencing the orogenic cycles’ existence and their relationship with the evolution of photosynthesis.
]]>Authors: Nikolay I. Alekseyev Anton P. Broyko Ivan K. Khmelnitskiy Alexander V. Kolyadin Vagarshak M. Aivazyan Ivan V. Oreshko
With its exceptional strength characteristics, diamond has some mechanical drawbacks, significant brittleness being among them. In particular, some HPHT-grown diamonds crack when the extreme parameters inherent to the diamond growth process gradually decrease. The cracking is caused by excessive stress due to the poor plastic properties of the diamond growth catalytic medium at certain stages of reducing the pressure and the temperature. An insulating container with the growth cell and heating circuit fragment inside can also make a significant contribution to the probability of cracking. This paper considers the possibility of minimizing the mechanical stress in the growth cell and, consequently, in the diamond crystal by choosing the optimal trajectory for the decrease in the pressure and temperature from diamond growth conditions to normal conditions.
]]>Authors: Michael M. Slepchenkov Pavel V. Barkov Dmitry A. Kolosov Olga E. Glukhova
In recent years, the possibility of combining graphene and carbon nanotubes has attracted much attention from researchers attempting to obtain new multifunctional hybrid materials with promising properties. Optoelectronics shows potential as a field of application for such hybrid structures. The variety of existing structural configurations of graphene-nanotube hybrids requires preliminary detailed studies of their optical properties by computer simulation methods. In this paper, we consider island-type graphene-nanotube hybrid films formed by AB-stacked bilayer graphene and single-walled carbon nanotubes (SWCNTs). In this case, bilayer graphene is located above the surface of the nanotube, forming areas with an increased density of carbon atoms, creating so-called “islands.” To meet the conditions of a real experiment, we chose chiral SWCNTs (12,6) with a diameter of 1.2 nm, which are most often synthesized in real experiments. All constructed atomistic models of bilayer graphene-chiral SWCNT films were tested for thermodynamic stability at room temperature and proved their suitability for research. Using Kubo-Greenwood formalism, we calculated the complex optical conductivity tensor and absorbance coefficient in the wavelengths of ultraviolet, visible, and near-infrared radiations. The photocurrent spectra are calculated based on the obtained absorption spectra and solar radiation spectra on the earth’s surface (AM1.5) and outside the earth’s atmosphere (AM0). The results of calculations revealed regularities in the influence of structural parameters (nanotube diameter, graphene width) on the optical and optoelectronic properties of graphene-chiral SWCNT (12,6) with an island structure.
]]>Authors: Marina A. Volosova Anna A. Okunkova
DLC coatings have low adhesive bond strength with the substrate and a high level of residual stresses. This paper is devoted to researching a complex of characteristics of a DLC-Si coating deposited on samples of SiAlON ceramics with intermediate coatings (CrAlSi)N pre-formed to improve the adhesive bond strength employing vacuum-plasma spraying. DLC-Si coatings were formed by chemical vapor deposition in a gas mixture of acetylene, argon, and tetramethylsilane supplied through a multichannel gas purge system controlling the tetramethylsilane volume by 1, 4, 7, and 10%. The SiAlON samples with deposited (CrAlSi)N/DLC-Si coatings with different silicon content in the DLC layer were subjected to XPS and EDX analyses. Tribological tests were carried out under conditions of high-temperature heating at 800C. The nanohardness and elasticity modulus of the rational (CrAlSi)N/DLC-Si coating with Si-content of 4.1% wt. were 26 ± 1.5 GPa and 238 ± 6 GPa, correspondingly. The rational composition of (CrAlSi)N/DLC-Si coating was deposited on cutters made of SiAlON ceramics and tested in high-speed machining of aircraft nickel-chromium alloy compared to uncoated and DLC-coated samples. The average operating time (wear resistance) of (CrAlSi)N/DLC-Si(4.1% wt.)-coated end mills before reaching the accepted failure criterion was 15.5 min when it was 10.5 min for the original cutters.
]]>Authors: Roberta Mota-Panizio Ana Assis Luís Carmo-Calado Catarina Nobre Andrei Longo José Silveira Maria Margarida Goncalves Paulo Brito
Waste insulation electrical cables (WIEC) currently do not have an added value, due to their physical–chemical characteristics. Carbonization is known to enhance feedstock properties, particularly fuel and material properties; as such, this article aimed to study the production and activation of biochars using WIEC and lignocellulosic biomass wastes as feedstock. Biochars were produced in a ceramic kiln with an average capacity of 15 kg at different temperatures, namely 300, 350 and 400 °C. After production, the biochars were further submitted to a washing process with water heated to 95 °C ± 5 °C and to an activation process with 2 N KOH. All biochars (after production, washing and activation) were characterized regarding an elemental analysis, thermogravimetric analysis, heating value, chlorine removal, ash content, apparent density and surface area. The main results showed that the increase in carbonization temperature from 300 to 400 °C caused the produced biochars to present a lower amount of oxygen and volatile matter, increased heating value, greater chlorine removal and increased ash content. Furthermore, the activation process increased the surface area of biochars as the production temperature increased. Overall, the carbonization of WIEC mixed with lignocellulosic wastes showed potential in enhancing these waste physical and chemical properties, with prospects to yield added-value products that activates biochar.
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