Search Results (40)

Extraction processes of alginates from Sargassum spp. generate a substantial number of solid residues that are commonly discarded. This study explores the sustainable transformation of these residues into nitrogen-doped biocarbon through chemical activation with KOH and nitrogen doping using urea. XRD, FTIR, SEM-EDX, Raman spectroscopy, BET surface area analysis, XPS, and CHNS elemental analysis were used to characterize the materials. The doped and activated biocarbon (BDA) demonstrated excellent physicochemical properties, including a specific surface area of 1790 m² g⁻¹ and a mesoporous structure. Electrochemical evaluation in alkaline media revealed a current density of −4.37 mA cm⁻², an onset potential of 0.922 E vs. RHE, and a half-wave potential of 0.775 E vs. RHE. Koutecky–Levich analysis indicated a two-electron reduction pathway. The superior performance was attributed to the synergistic effects of high surface area, nitrogen functionalities (pyridinic-N and pyrrolic-N), and enhanced accessibility of active sites. These results highlight the potential of waste-derived, nitrogen-doped biocarbon as a sustainable and low-cost alternative for ORR electrocatalysis in alkaline fuel cells. Full article

Oil palm kernel shell is an abundant agricultural waste generated by the palm oil industry. To achieve sustainable use of this waste, oil palm kernel shells were converted into valuable resources as active biocarbons. A two-stage preparation method involving N₂ pyrolysis, followed by CO₂ activation, was used to produce the active biocarbon. The optimum pyrolysis conditions that produced the largest BET surface area of 519.1 m²/g were a temperature of 600 °C, a hold time of 2 h, a nitrogen flow rate of 150 cm³/min, and a heating rate of 10 °C/min. The optimum activation conditions to prepare the active biocarbon with the largest micropore surface area or the best micropore/BET surface area combination were a temperature of 950 °C, a CO₂ flow rate of 300 cm³/min, a heating rate of 10 °C/min, and a hold time of 3 h, yielding BET and micropore surface areas of 1232.3 and 941.0 m²/g, respectively, and consisting of 76.36% of micropores for the experimental optimisation technique adopted here. This study underscores the importance of optimising both the pyrolysis and activation conditions to produce an active biocarbon with a maximum micropore surface area for gaseous adsorption applications, especially to capture CO₂ greenhouse gas, to mitigate global warming and climate change. Such a comprehensive and detailed study on the conversion of oil palm kernel shell into active biocarbon is lacking in the open literature. The research results provide a practical blueprint on the process parameters and technical know-how for the industrial production of highly microporous active biocarbons prepared from oil palm kernel shells. Full article

The oxygen evolution reaction (OER) plays a central role as an anode in electrocatalytic processes such as energy conversion and storage and the generation of molecular oxygen from the electrolysis of water. Currently, precious metal oxides such as IrO₂ and RuO₂ are recognized as reference OER electrocatalysts with reasonably high activity; however, their widespread use in practical devices has been severely hindered by their high cost and scarcity. It is essential to design alternative OER electrocatalysts made of low-cost and abundant earth elements with significant activity and robustness. We report four new nanocellulose-derived Fe–zeolite nanocomposites, namely Fe/Zeolite@CCNC (1), Fe/Zeolite@CCNF (2), Fe/Zeolite/CNT@CCNC (3), and Fe/Zeolite/CNT@CCNF (4). Two different types of nanocellulose were investigated: nanocellulose nanofibrils and nanocellulose nanocrystals. Characterization with TEM, SEM-EDS, PXRD, and XPS is reported. The nanocomposites exhibited electrocatalytic activity for OER that varies based on the origin of biocarbon and the composition content. The effect of adding carbon nanotubes to the nanocomposites was studied, and an improvement in OER catalysis was observed. The electrochemical double-layer capacitance and electrochemical impedance spectroscopy of the nanocomposites are reported. The nanocomposite 3 exhibited the highest performance, with an onset potential value of 1.654 V and an overpotential of 551 mV, which exceeds the activity of RuO₂ for OER catalysis at 10 mA/cm² in the glassy carbon electrode. A 24 h chronoamperometry study revealed that the catalyst is active for ~2 h under continuous operating conditions. BET surface analysis showed that the crystalline nanocellulose-derived composite exhibited 301.47 m²/g, and the fibril nanocellulose-derived composite exhibited 120.39 m²/g, indicating that the increased nanoporosity of the former contributes to the increase in OER catalysis. Full article

In the energy sector and in other types of industries (cement, iron/steel, chemical and petrochemical), highly roasted coffee ground residue can be used as a source material for producing bioadsorbents suitable for CO₂ capture. In this study, a bioadsorbent was produced in a two-step process involving biowaste carbonization and biocarbon activation within a KOH solution. The physicochemical properties of the bioadsorbent were assessed using LECO, TG, SEM, BET and FT-IR methods. Investigating the CO₂, O₂ and N₂ equilibrium adsorption capacity using an IGA analyzer allowed us to calculate CO₂ selectivity factors. We assessed the influence of exhaust gas carbon dioxide concentration (16%, 30%, 81.5% and 100% vol.) and adsorption step temperature (25 °C, 50 °C and 75 °C) on the CO₂ adsorption capacity of the bioadsorbent. We also investigated its stability and regenerability in multi-step adsorption–desorption using a TG-Vacuum system, simulating the VSA process and applying different pressures in the regeneration step (30, 60 and 100 mbar_abs). The tests conducted assessed the possibility of using a produced bioadsorbent for capturing CO₂ using the VSA technique. Full article

This study presents research on the production of activated biocarbons derived from herbal waste. Sage stems were chemically activated with two activating agents of different chemical natures—H₃PO₄ and K₂CO₃—and subjected to two thermal treatment methods: conventional and microwave heating. The effect of the activating agent type and heating method on the basic physicochemical properties of the resulting activated biocarbons was investigated. These properties included surface morphology, elemental composition, ash content, pH of aqueous extracts, the content and nature of surface functional groups, points of zero charge, and isoelectric points, as well as the type of porous structure formed. In addition, the potential of the prepared carbonaceous materials as adsorbents of model organic (represented by Triton X-100 and methylene blue) and inorganic (represented by iodine) pollutants was assessed. The influence of the initial adsorbate concentration (5–150 (dye) and 10–800 mg/dm³ (surfactant)), temperature (20–40 °C), and pH (2–10) of the system on the efficiency of contaminant removal from aqueous solutions was evaluated. The adsorption kinetics were also investigated to better understand the rate and mechanism of contaminant uptake by the prepared activated biocarbons. The results showed that materials activated with orthophosphoric acid exhibited a significantly higher sorption capacity for all tested adsorbates compared to their potassium carbonate-activated counterparts. Microwave heating was found to be more effective in promoting the formation of a well-developed specific surface area (471–1151 m²/g) and porous structure (mean pore size 2.17–3.84 nm), which directly enhanced the sorption capacity of both organic and inorganic contaminants. The maximum adsorption capacities for iodine, methylene blue, and Triton X-100 reached the levels of 927.0, 298.4, and 644.3 mg/g, respectively, on the surface of the H₃PO₄-activated sample obtained by microwave heating. It was confirmed that the heating method used during the activation step plays a key role in determining the physicochemical properties and sorption efficiency of activated biocarbons. Full article

The application of biochar is extensively recognized as an effective strategy to enhance soil ecosystem services. However, its combined effect with beneficial microorganisms, such as Trichoderma, still requires further investigation to understand its impact on soil microbiota and nutrient cycling processes. To address this gap, this study aimed to evaluate the effect of biochar produced from on-farm winery waste, specifically grape stalks (GSB) and grape fermentation residues (GFB), generated after wine production, when co-applied with Trichoderma aureoviride URM 5158 and Trichoderma hamatum URM 6656 in soil cultivated with Malbec grapevines. Our findings reveal that both types of biochar and Trichoderma promoted changes in soil properties. The application of GSB biochar combined with T. hamatum increased grape productivity, while GFB biochar enhanced soil enzymatic activities, particularly those expressed per unit of microbial biomass carbon. Additionally, biochar applications increased pH, phosphorus, potassium, organic carbon, and microbial biomass carbon of the soil. Soils treated with the GFB + T. hamatum treatment exhibited an increase of 569.23% in microbial biomass carbon compared to the control. The results of this study provide substantial evidence that biochar and Trichoderma can be used to improve the chemical and biological properties of vineyard soils, increasing nutrient availability, especially carbon. These effects may contribute to soil fertility by promoting a more favorable environment for microbiota development and grapevine growth. This is the first field study to investigate the impact of on-farm winery waste transformed into biochar, combined with Trichoderma isolates, on Malbec grapevines. Full article

The aim of this paper was to obtain activated biocarbons from the natural biomass of horse chestnut seeds (Aesculus hippocastanum) by physical activation with two different activating agents, carbon dioxide and water vapor, and to evaluate their structural and adsorption properties. The effect of the pyrolysis atmosphere on the surface development and porosity as well as the structure and adsorption properties of the materials in relation to the selected organic adsorbates (tetracycline (TC), naproxen (NPX), and methyl orange (MO)), which may constitute a potential contamination of the aquatic environment, was evaluated. Activated biocarbons were characterized using N₂ low-temperature adsorption/desorption, Raman and FT-IR spectroscopy, and thermogravimetric analysis (TGA). The nature of the surface (pH_pzc and Boehm titration) was also studied. Micro/mesoporous biocarbons were obtained with an S_BET area in the range of ~534 to 646 m²/g, in which micropores constituted ~70%. It was proved that the obtained materials are characterized by high adsorption values (~120 mg/g, ~150 mg/g, and ~252 mg/g) and removal rates %R (~80%, ~95%, and ~75%) for TC, NPX, and MO, respectively. The results indicate that chestnut-derived activated biocarbons are a promising, cost-effective and environmentally friendly alternative for removing organic contaminants from aqueous solutions. Future research should focus on optimizing activation parameters and assessing the long-term performance of adsorbents. Full article

This research focuses on the synthesis and characterization of advanced materials for hydrogen storage. Two biocarbon samples were synthesized from Sargassum spp. The first was activated with KOH (SKPT) and the second was doped with sulfur (SSKTP); both were obtained through pyrolysis at 900 °C. The sulfur-doped biocarbon (SSKTP), with its high specific surface area (2377 m² g^ࢤ1), exhibited enhanced electrocatalytic properties, making it an efficient candidate for hydrogen storage applications. Various characterization techniques were employed to study the relationship between physicochemical properties and hydrogen uptake. The presence of micropores and sulfur doping significantly improved hydrogen uptake at 45 °C and 50 bar, where SSKTP achieved 0.40 wt%. In comparison, the non-doped biocarbon (SKPT) showed a lower hydrogen storage capacity of 0.33 wt%, with a specific surface area of 1620 m² g^ࢤ1. The results highlight the potential of sulfur-doped activated biocarbon as a functional material in energy conversion systems, specifically for electrocatalytic hydrogen storage processes. This study demonstrates a sustainable approach to utilizing biomass waste for advanced electrocatalysts, contributing to renewable energy solutions. Full article

This review analyzes in detail the topic of supercapacitors based on biochar technologies, including their advantages, disadvantages, and development potential. The main topic is the formation of precursors in the process of pyrolysis and activation, and the possibility of the application of biochar itself in various fields is brought closer. The structure, division, and principle of operation of supercondensates are discussed, where their good and bad sides are pointed out. The current state of the scientific and legal knowledge on the topic of biocarbon and its applications is verified, and the results of many authors are compared to examine the current level of the research on supercapacitors based on biochar electrodes created from lignocellulosic biomass. Current application sites for supercapacitors in transportation, electronics, and power generation (conventional and unconventional) are also examined, as is the potential for further development of the technology under discussion. Full article

The increase in environmental pollution due to the development of industry and human activity has resulted in intensive development of research on the possibility of its purification. A very effective method is the pollutants’ adsorption from the air and water environment. For adsorption to be effective, materials with a specific structure and a well-developed surface decorated with numerous functionalities, e.g., biocarbons (BC), are necessary. An effective method of activating biocarbons is mechanochemical milling, an environmentally friendly procedure. This paper describes the possibility of using mechanochemical activation (MChA) of non-porous biocarbons to develop surface and porosity for their use in processes of pollutant adsorption. BC was characterized based on N₂ adsorption, thermogravimetry (TGA), SEM/EDS imaging, Fourier (ATR-FTIR) and Raman spectroscopies, as well as titration using the Boehm method and determination of zeta potential. The adsorption capacity of BC for methylene blue (MB) was studied. It was proven that the solvent-free MChA made it possible to obtain microporous biocarbons, causing an intensive increase in the surface area and pore volume and the generation of oxygen functionalities. The biocarbons had predominantly acidic (mainly carboxylic) or basic functionalities and exhibited an amorphous structure. BC proved to be effective in adsorbing MB from aqueous solutions. Full article

The rising concentration of CO₂ in the atmosphere is approaching critical levels, posing a significant threat to life on Earth. Porous carbons derived from biobased materials, particularly waste byproducts, offer a viable solution for selective CO₂ adsorption from large-scale industrial sources, potentially mitigating atmospheric CO₂ emissions. In this study, we developed highly porous carbons from lemon peel waste through a two-step process, consisting of temperature pretreatment (500 °C) followed by chemical activation by KOH at 850 °C. The largest specific surface area (2821 m²/g), total pore volume (1.39 cm³/g), and micropore volume (0.70 cm³/g) were obtained at the highest KOH-to-carbon ratio of 4. In contrast, the sample activated with a KOH-to-carbon ratio of 2 demonstrated the greatest micropore distribution. This activated biocarbon exhibited superior CO₂ adsorption capacity, reaching 5.69 mmol/g at 0 °C and 100 kPa. The remarkable adsorption performance can be attributed to the significant volume of micropores with diameters smaller than 0.859 nm. The Radke–Prausnitz equation, traditionally employed to model the adsorption equilibrium of organic compounds from liquid solutions, has been shown to be equally applicable for describing the gas–solid adsorption equilibrium. Furthermore, equations describing the temperature dependence of the Radke–Prausnitz equation’s parameters have been developed. Full article

Land-use change is an important factor affecting terrestrial carbon balance, and it is crucial to explore the response of terrestrial carbon stocks to land-use change, especially in the Songnen Plain, which faces a fierce conflict between the rapid growth of production activities and ecosystem degradation. In this study, we measured soil organic carbon and vegetation biocarbon stocks in the Songnen Plain based on IPCC-recommended methodologies, and explored the characteristics of carbon stock changes in land-use trajectories, land-use drivers, and specific land-use change scenarios (cropland cultivation, returning cropland to forests, the expansion of land for construction, deforestation, greening, and land degradation). The results showed that soil organic carbon stock in the Songnen Plain decreased by 1.63 × 10⁵ t, and vegetation biocarbon stock increased by 2.10 × 10⁷ t from 2005 to 2020. Human factors and natural factors jointly contributed to the land-use change, but the extent of the role of human factors was greater than that of natural factors. The increase in land-use trajectory led to the decrease in soil organic carbon stock and the increase in vegetation biocarbon stock. There was no difference in the effects of human-induced and natural-induced land-use changes on vegetation biocarbon stocks, but the effects on soil organic carbon stocks were diametrically opposite, increasing by 43.27 t/km² and decreasing by 182.02 t/km², respectively. The reclamation of arable land, returning cropland to forests, and greening led to a net increase in terrestrial carbon stocks (+813,291.84 t), whereas land degradation, deforestation, and land-use expansion led to a decrease in terrestrial carbon stocks (−460,710.2 t). The results of this study can provide a reference for the adjustment of land-use structure and the increase in terrestrial carbon stock in the Songnen Plain. Full article

A series of new granular carbonaceous adsorbents was prepared via single-stage physical and chemical activation of walnut shells. Their suitability for removing various types of organic pollutants (represented by dyes, surfactants and water-soluble polymers) from the liquid phase was assessed. The activation of the precursor was carried out with CO₂ and H₃PO₄ using conventional heating. Activated biocarbons were characterized in terms of chemical composition, acidic–basic nature of the surface, textural and electrokinetic properties as well as thermal stability. Depending on the type of activating agent used during the activation procedure, the obtained biocarbons differed in terms of specific surface area (from 401 to 1361 m²/g) and the type of porous structure produced (microporosity contribution in the range of 45–75%). Adsorption tests proved that the effectiveness of removing organic pollutants from the liquid phase depended to a large extent on the type of prepared adsorbent as well as the chemical nature and the molecular size of the adsorbate used. The chemically activated sample showed greater removal efficiency in relation to all tested pollutants. Its maximum adsorption capacity for methylene blue, poly(acrylic acid), poly(ethylene glycol) and Triton X-100 reached the levels of 247.1, 680.9, 38.5 and 61.8 mg/g, respectively. Full article

This article describes the production of bioadsorbents coming from seven different kinds of organic waste, produced in huge quantities in households, in a two-stage process. In order to determine the influence of the process parameters of carbonization (I stage) and activation with potassium hydroxide solution (II stage), the following analysis of the physicochemical properties of each sample at each stage processing was performed: base elemental composition, structure properties, surface morphology, thermal stability, crystallinity, and transmittance spectra characteristic bands. There was a lack of research on samples after each stage of waste processing in the literature. Addressing this allowed us to evaluate the transformative potential of each kind of organic waste included in the research and select the best waste for the production of bioadsorbents commonly used in environmental protection. Moreover, the results were compared with the ones in the literature. The utilization of particular kinds of organic waste seems to be especially important taking into account the strategy of waste management and sustainable development. Full article

Onion waste, particularly onion skin, is a widely generated waste material, and harnessing its potential for energy storage aligns with sustainable development goals. Despite the high specific surface area exhibited by biocarbon derived from onion skin, its Li-ion storage performance is not desirable. In this study, biocarbon derived from purple onion skin serves as the substrate for accommodating cobalt oxide (Co₃O₄) through a hydrothermal method, employing Co(NO₃)₂·6H₂O at various concentrations, and with and without prior activation using KOH treatment. The resulting samples undergo comprehensive analyses, including phase, morphological, surface, and electrochemical characterizations. The Co₃O₄ decoration on activated carbon derived from onion skin, synthesized using Co(NO₃)₂·6H₂O at a concentration of 1 M, reveals a porous structure with a surface area of 702 m²/g, featuring predominant pore sizes of less than 5 nm. Significantly, the Li-ion storage performance of this sample surpasses that of alternative samples, demonstrating a remarkable reversible capacity of 451 mAh/g even after 500 cycles at an elevated current density of 2000 mAh/g. The charge transfer resistance of the sample (110.3 Ω) is found to be substantially lower than that of the sample prepared using carbonized onion skin biomass without activation. This research introduces an innovative approach leveraging onion skin waste as a template for Co₃O₄ decoration, thereby fabricating high-performance anodes for lithium-ion batteries. Full article