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Volume 8
Issue 4
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C, Volume 8, Issue 4 (December 2022) – 34 articles

Cover Story (view full-size image): Carbon dots (CDots) are defined as small carbon nanoparticles with surface organic functionalization, a definition which is literally based on their description when CDots were originally discovered. However, a more popular approach to materialize the dot structure as defined has been to create the required nanocarbon domains via thermal carbonization of organic precursors, though the samples thus obtained are morphologically composite-like, more appropriately denoted as “nano-carbon/organic hybrids”. For the significant structural and morphological differences between classically synthesized CDots and the carbonization-produced hybrids, some of their optical spectroscopic properties are similar, but the photoinduced antimicrobial outcomes are dramatically different. View this paper
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18 pages, 2986 KiB  
Article
Ferromagnetic Biochar Prepared from Hydrothermally Modified Calcined Mango Seeds for Fenton-like Degradation of Indigo Carmine
by Aurelien Bopda, Sandrale Grace Mokue Mafo, Josiane Nguimatsia Ndongmo, Georges Teikam Kenda, Cyrille Ghislain Fotsop, Idris-Hermann Tiotsop Kuete, Christian Sadeu Ngakou, Donald Raoul Tchuifon Tchuifon, Arnaud Kamdem Tamo, George Ndifor-Angwafor Nche and Solomon Gabche Anagho
C 2022, 8(4), 81; https://doi.org/10.3390/c8040081 - 19 Dec 2022
Cited by 14 | Viewed by 2603
Abstract
Biochar and ferromagnetic biochar obtained from the pyrolysis of dried mango seeds and modified using a hydrothermal method were used as catalyst for the heterogeneous degradation of indigo carmine in an aqueous medium. These prepared biochars were characterized using different techniques: Fourier transform [...] Read more.
Biochar and ferromagnetic biochar obtained from the pyrolysis of dried mango seeds and modified using a hydrothermal method were used as catalyst for the heterogeneous degradation of indigo carmine in an aqueous medium. These prepared biochars were characterized using different techniques: Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The analyses of the results revealed the presence of iron oxide in the form of magnetite (Fe3O4) in the catalyst. The catalytic tests carried out with this composite material showed a significant degradation of indigo carmine. The maximum degradation of indigo carmine in the aqueous solution was reached after 240 min of agitation. The Fenton degradation process using irradiation with a 100 W electric lamp and hydrogen peroxide (concentration 4 mol/L) showed the best results at pH = 3. From this study, it emerged that the second-order kinetic model better described the degradation process, and it gave lower half-lives compared to those obtained with the first-order kinetic law. The study also showed that ferromagnetic biochar could be prepared from mango seeds and used for the degradation of indigo carmine in an aqueous solution. Full article
(This article belongs to the Special Issue Carbon-Based Catalyst (2nd Edition))
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13 pages, 3239 KiB  
Article
Pull-Out of Pristine and Functionalized Carbon Nanotubes from Cement: A Molecular Modelling Study
by Isabel Lado-Touriño
C 2022, 8(4), 80; https://doi.org/10.3390/c8040080 - 16 Dec 2022
Cited by 1 | Viewed by 2036
Abstract
Carbon nanotubes (CNTs) are widely used as reinforcements in cement-based composites. The improvement in the mechanical properties of the resulting materials depends on the characteristics of the interface formed between CNTs and the cement matrix. The experimental characterization of the interfacial properties of [...] Read more.
Carbon nanotubes (CNTs) are widely used as reinforcements in cement-based composites. The improvement in the mechanical properties of the resulting materials depends on the characteristics of the interface formed between CNTs and the cement matrix. The experimental characterization of the interfacial properties of these composites is still limited and hard to achieve with currently available technologies. In this work, molecular dynamics and molecular mechanics pull-out simulations of pristine and functionalized CNTs, taken from a tobermorite crystal, were carried out to study interfacial shear strength (ISS) from an atomic perspective. ISS was calculated from the potential energy of the systems. The effects of the CNT diameter and the degree of functionalization on the pull-out process were analyzed according to the ISS and non-bonded energy results. The influence of H-bonding and electrostatic interactions between the CNT and the matrix were also studied. The results show that ISS decreases with increasing CNT radius for pristine CNTs and depends upon the number of H-bonds for functionalized CNTs. ISS values are positively correlated to Enon-bonded energy, which is related to the number of carboxyl groups on the CNT surface. A high degree of functionalization increases both the number of H-bonds and the number of Ca2+-O interactions between the CNT and the tobermorite surface. This results in a stronger interfacial interaction and, therefore, an elevated ISS value. Full article
(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)
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8 pages, 2254 KiB  
Article
Plasma Electrochemical Synthesis of Graphene-Phosphorene Composite and Its Catalytic Activity towards Hydrogen Evolution Reaction
by Valeriy K. Kochergin, Natal’ya S. Komarova, Alexander S. Kotkin, Roman A. Manzhos, Vladimir P. Vasiliev and Alexander G. Krivenko
C 2022, 8(4), 79; https://doi.org/10.3390/c8040079 - 14 Dec 2022
Cited by 3 | Viewed by 2212
Abstract
For the first time, graphene-phosphorene structures were synthesized using the plasma-assisted electrochemical method. The catalytic activity of the composite obtained in the electrolytic plasma mode and its mixtures with few-layer graphene structures toward the hydrogen evolution reaction was studied. A substantial increase in [...] Read more.
For the first time, graphene-phosphorene structures were synthesized using the plasma-assisted electrochemical method. The catalytic activity of the composite obtained in the electrolytic plasma mode and its mixtures with few-layer graphene structures toward the hydrogen evolution reaction was studied. A substantial increase in the catalytic activity of the phosphorene structures towards the hydrogen evolution reaction was realized by mixing them with few-layer graphene structures. The catalyst demonstrates excellent activity towards the hydrogen evolution reaction in alkaline media with a low overpotential of 940 mV at a current density of 10 mA·cm−2 and a small Tafel slope of 130 mV dec−1. Full article
(This article belongs to the Special Issue Carbon-Based Catalyst (2nd Edition))
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23 pages, 8204 KiB  
Article
OctCarb—A GNU Octave Script for the Analysis and Evaluation of Wide-Angle Scattering Data of Non-Graphitic Carbons
by Oliver Osswald and Bernd M. Smarsly
C 2022, 8(4), 78; https://doi.org/10.3390/c8040078 - 9 Dec 2022
Cited by 4 | Viewed by 3600
Abstract
We present a free software script operating in GNU Octave for the refinement of wide-angle X-ray and neutron scattering (WAXS/WANS) data of non-graphitic carbons (NGCs). The refinement script (OctCarb) is based on the evaluation approach of Ruland and Smarsly (2002). As [...] Read more.
We present a free software script operating in GNU Octave for the refinement of wide-angle X-ray and neutron scattering (WAXS/WANS) data of non-graphitic carbons (NGCs). The refinement script (OctCarb) is based on the evaluation approach of Ruland and Smarsly (2002). As result, up to 14 physically meaningful parameters such as the layer extension La, the stack height Lc, as well as the degree of disorder of the graphenes and their stacking are obtained through a well-established fitting routine. In addition, background scattering based on specific physical phenomena and different correction parameters such as polarization and absorption can be considered. Since the complex mathematical calculations are implemented and performed in the background, with only a few settings to be made, the software was designed to be usable by inexperienced users. As another key feature, Octave and thus OctCarb run on all common operating systems (Windows, MacOS and Linux), and can even be used on high-performance computing clusters (HPCs) to perform multiple calculations at once. In addition to this, the whole refinement can be performed within minutes, and it is possible to tweak and optimize it for special purposes and measuring geometries. These features make OctCarb useful for all scientists dealing with the characterization of NGCs by X-ray or neutron scattering techniques. Full article
(This article belongs to the Special Issue Characterization of Disorder in Carbons (2nd Edition))
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25 pages, 4041 KiB  
Review
Technology Features of Diamond Coating Deposition on a Carbide Tool
by Evgeny Ashkinazi, Sergey Fedorov, Alexander Khomich, Vladimir Rogalin, Andrey Bolshakov, Dmitry Sovyk, Sergey Grigoriev and Vitaly Konov
C 2022, 8(4), 77; https://doi.org/10.3390/c8040077 - 9 Dec 2022
Cited by 7 | Viewed by 4430
Abstract
The production of carbide tools with polycrystalline diamond coatings, which are used for processing modern carbon composite materials, includes a number of technological techniques that ensure reliable adhesion of the coating to the substrate. This review examines these features of substrate-surface pretreatment to [...] Read more.
The production of carbide tools with polycrystalline diamond coatings, which are used for processing modern carbon composite materials, includes a number of technological techniques that ensure reliable adhesion of the coating to the substrate. This review examines these features of substrate-surface pretreatment to improve adhesion, which includes chemical etching, mechanical hardening, modification by ion beams, plasma treatment and application of buffer layers between the substrate and the coating. This review also discusses the advantages and disadvantages of the most common methods for obtaining polycrystalline diamond coatings using hot filament and deposition of coatings from microwave plasma. Full article
(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)
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17 pages, 2091 KiB  
Review
Bonding of Carbon Steel Bars in Concrete Produced with Recycled Aggregates: A Systematic Review of the Literature
by Elvys Dias Reis, Henrique Comba Gomes, Rogério Cabral de Azevedo, Flávia Spitale Jacques Poggiali and Augusto Cesar da Silva Bezerra
C 2022, 8(4), 76; https://doi.org/10.3390/c8040076 - 7 Dec 2022
Cited by 4 | Viewed by 2801
Abstract
Civil construction is essential for the world economy and the largest generator of construction and demolition waste (CDW), mainly due to a lack of planning, technological control, and restoration execution, among other factors. While efforts are made to minimize this waste generation, one [...] Read more.
Civil construction is essential for the world economy and the largest generator of construction and demolition waste (CDW), mainly due to a lack of planning, technological control, and restoration execution, among other factors. While efforts are made to minimize this waste generation, one possible application for CDW is its incorporation into Portland cement-based materials as recycled aggregates, in partial or total replacement of natural aggregates. However, for CDW use to be feasible, the structure performance and safety must be assured, and the adherence between concrete and reinforcement bars, in this context, is a fundamental mechanism. With this perspective, this paper aims to investigate the influence of recycled aggregate on steel–concrete bonding. To this end, the SREE (Systematic Review for Engineering and Experiments) method was employed as a novelty, including a methodology quality analysis, to search and analyze relevant scientific articles published in the last ten years. The results revealed that the use of CDW as recycled aggregates in concrete worsens the steel–concrete bonding, and that ribbed steel bar seems to be the best option when employed in RC structures built with CDW-concrete, although the bar diameter and the anchorage length still need further investigations, and that CDW-concrete’s use can significantly contribute to reducing the emission of greenhouse gases and to capturing CO2 from the atmosphere. Therefore, further investigations should focus on the real influence of recycled aggregate type and replacement content, bar diameter, anchorage length, and CDW’s potential to capture CO2. Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection)
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15 pages, 2915 KiB  
Article
One-Step Electropolymerization of Azure A and Carbon Nanomaterials for DNA-Sensor Assembling and Doxorubicin Biosensing
by Anna Porfireva, Ekaterina Begisheva, Alexey Rogov and Gennady Evtugyn
C 2022, 8(4), 75; https://doi.org/10.3390/c8040075 - 6 Dec 2022
Cited by 5 | Viewed by 2404
Abstract
New highly sensitive voltammetric DNA-sensors have been developed for the detection of cytostatic drug doxorubicin based on Azure A electropolymerized on various carbon nanomaterials, i.e., functionalized multi-walled carbon nanotubes (fMWCNTs) and carbon black (CB). Carbon materials promote electropolymerization of the Azure A dye [...] Read more.
New highly sensitive voltammetric DNA-sensors have been developed for the detection of cytostatic drug doxorubicin based on Azure A electropolymerized on various carbon nanomaterials, i.e., functionalized multi-walled carbon nanotubes (fMWCNTs) and carbon black (CB). Carbon materials promote electropolymerization of the Azure A dye applied as a matrix for DNA molecules saturated with methylene blue (MB) molecules. Interaction with the intercalator (doxorubicin) liberates the MB molecules and changes redox activity. The doxorubicin concentration ranges reached by cyclic voltammetry were from 0.1 pM to 100 nM (limit of detection, LOD, 0.03 pM) for the biosensor based on CB, and from 0.3 pM to 0.1 nM (LOD 0.3 pM) for that based on fMWCNTs. DNA-sensors were tested on spiked samples of artificial serum, and biological and pharmaceutical samples. The DNA-sensors can find further application in the monitoring of the doxorubicin residuals in cancer treatment, as well as for pharmacokinetics studies. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)
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11 pages, 2443 KiB  
Article
Testing of Diamond Electrodes as Biosensor for Antibody-Based Detection of Immunoglobulin Protein with Electrochemical Impedance Spectroscopy
by Martin Menzler, Charity S. G. Ganskow, Maximilian Ruschig, Essam Moustafa, Volker Sittinger, Kristina Lachmann, Esther Veronika Wenzel, Giulio Russo, Philipp Klahn and Jan Gäbler
C 2022, 8(4), 74; https://doi.org/10.3390/c8040074 - 6 Dec 2022
Viewed by 2095
Abstract
To control the increasing virus pandemics, virus detection methods are essential. Today’s standard virus detections methods are fast (immune assays) or precise (PCR). A method that is both fast and precise would enable more efficient mitigation measures and better life comfort. According to [...] Read more.
To control the increasing virus pandemics, virus detection methods are essential. Today’s standard virus detections methods are fast (immune assays) or precise (PCR). A method that is both fast and precise would enable more efficient mitigation measures and better life comfort. According to recent papers, electrochemical impedance spectroscopy (EIS) has proven to detect viruses fast and precise. Boron-doped diamond (BDD) was used as a high-performance electrode material in these works. The aim of this work was to perform an initial test of BDD-based EIS for biosensing. As an easily available standard biomaterial, human immunoglobulin G (IgG) was used as analyte. Niobium plates were coated via hot-filament activated chemical vapor deposition with polycrystalline diamond, and doped with boron for electrical conductivity. An anti-human IgG antibody was immobilised on the BDD electrodes as a biosensing component. Four different analyte concentrations up to 1.1 µg per litre were tested. During EIS measurements, both impedance over frequency curves and Nyquist plot demonstrated no clear sign of a change of the charge transfer resistance. Thus, no positive statement about a successful biosensing could be made so far. It is assumed that these issues need to be investigated and improved, including the relation of BDD electrode size to electrolyte volume, termination of the BDD electrodes (H, O) for a successful functionalisation and EIS frequency range. The work will be continued concerning these improvement issues in order to finally use virus materials as analyte. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)
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15 pages, 686 KiB  
Article
Development of the Correlation Model between Biogas Yield and Types of Organic Mass and Analysis of Its Key Factors
by Tetiana Mirzoieva, Nazar Tkach, Vitalii Nitsenko, Nataliia Gerasymchuk, Olga Tomashevska and Oleksandr Nechyporenko
C 2022, 8(4), 73; https://doi.org/10.3390/c8040073 - 5 Dec 2022
Cited by 2 | Viewed by 2132
Abstract
Since European society is experiencing an aggravation of the issue of energy security, the production of renewable energy is becoming increasingly important. The advantages of biofuel—in particular, biogas—and the positive effects of the development of its production are summarized within the framework of [...] Read more.
Since European society is experiencing an aggravation of the issue of energy security, the production of renewable energy is becoming increasingly important. The advantages of biofuel—in particular, biogas—and the positive effects of the development of its production are summarized within the framework of the problem statement. It is emphasized that the production of biogas from various renewable raw materials causes economic, ecological, and social effects. The development of biogas production can be especially active in combination with the development of the agricultural sphere. In response to today’s demand, the authors in this research present a model of the correlation between the output of biogas from different types of organic mass and specify the factors affecting it. In particular, a multiple econometric model of the relationship between the output of biogas from different types of organic mass and the content of dry organic matter and the share of possible methane content in organic matter was built; the density of the connection between the factors and the resulting feature was evaluated; the tightness of the general relationship (influence) of independent variables on the dependent variable was checked using the coefficient of determination; and the reliability of the correlation characteristics was estimated using Fisher’s and Student’s tests. As a result, with the use of convincing evidence—in particular, taking into account the potential of the Ukrainian agricultural sector—the feasibility of further development of biogas production in combination with the development of agricultural production is substantiated. Full article
(This article belongs to the Special Issue Biomass—a Renewable Resource for Carbon Materials)
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24 pages, 3185 KiB  
Review
Carbon Nanomaterials-Based Electrically Conductive Scaffolds to Repair the Ischaemic Heart Tissue
by Arsalan Ul Haq, Felicia Carotenuto, Federica Trovalusci, Fabio De Matteis and Paolo Di Nardo
C 2022, 8(4), 72; https://doi.org/10.3390/c8040072 - 4 Dec 2022
Cited by 3 | Viewed by 2973
Abstract
Ischaemic heart diseases are the leading causes of morbidity around the world and pose serious socio-economic burdens. Ischaemic events, such as myocardial infarction, lead to severe tissue damage and result in the formation of scar tissue. This scar tissue, being electrically inert, does [...] Read more.
Ischaemic heart diseases are the leading causes of morbidity around the world and pose serious socio-economic burdens. Ischaemic events, such as myocardial infarction, lead to severe tissue damage and result in the formation of scar tissue. This scar tissue, being electrically inert, does not conduct electrical currents and thus generates lethal arrhythmias. The ventricle dilates with time due to asynchronous beating due to the scar, and it eventually leads to total heart failure. The current pharmacological approaches only cure heart failure symptoms without inducing tissue regeneration. Therefore, heart transplant remains the gold standard to date, but the limited organ donors and the possibility of immune rejection make this approach elusive. Cardiac tissue engineering has the potential to address this issue by engineering artificial heart tissues using 3D scaffolds cultured with cardiac stem cells. Compared with the traditional non-conductive scaffold, electroconductive scaffolds can transfer feeble electric currents among the cultured cells by acting as a “wire”. This improves intercellular communication and synchronisation that otherwise is not possible using non-conductive scaffolds. This article reviews the recent advances in carbon nanomaterials-based electroconductive scaffolds, their in vitro/in vivo efficacy, and their potential to repair ischaemic heart tissue. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)
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10 pages, 1672 KiB  
Article
Study of Hybrid Modification with Humic Acids of Environmentally Safe Biodegradable Hydrogel Films Based on Hydroxypropyl Methylcellulose
by Denis Miroshnichenko, Katerina Lebedeva, Anna Cherkashina, Vladimir Lebedev, Oleksandr Tsereniuk and Natalia Krygina
C 2022, 8(4), 71; https://doi.org/10.3390/c8040071 - 3 Dec 2022
Cited by 14 | Viewed by 2121
Abstract
The possibility of increasing the complexity of the operational properties of environmentally safe biodegradable polymer hydrogel materials based on hydroxypropyl methylcellulose due to modification by humic acids from lignite is considered. As a result of this research, environmentally safe hybrid hydrogel films with [...] Read more.
The possibility of increasing the complexity of the operational properties of environmentally safe biodegradable polymer hydrogel materials based on hydroxypropyl methylcellulose due to modification by humic acids from lignite is considered. As a result of this research, environmentally safe hybrid hydrogel films with antibacterial properties were received. In the framework of physicochemical studies, it was determined by IR spectroscopy that hydroxypropyl methylcellulose modified with humic acids hybridmaterials are received by the mechanism of matrix synthesis, which is accompanied by hydroxypropyl methylcellulose crosslinking through multipoint interaction with the carboxyl group of humic acids. Regularities in terms of changes in water absorption, gelation time, and mold emergence time regarding the environmentally safe biodegradable polymer hydrogel materials based on hydroxypropyl methylcellulose depending on the humic acid content were revealed. It was established that the optimal humic acid content in environmentally safe biodegradable hydrogel films with bactericidal properties based on hydroxypropyl methylcellulose is 15% by mass. It was also established that the hybrid modification of hydroxypropyl methylcellulose with humic acids allows them to preserve their biodegradation properties while giving them antibacterial properties. The environmentally safe biodegradable hydrogel films with bactericidal properties based on hydroxypropyl methylcellulose and humic acids are superior in their operational characteristics to known similar biodegradable hydrogel films based on natural biopolymers. Full article
(This article belongs to the Special Issue Biomass—a Renewable Resource for Carbon Materials)
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13 pages, 4143 KiB  
Article
Robust Packaging of Vertically Aligned Graphite Substrate by Copper Micro-Rib Structuring
by Tatsuhiko Aizawa, Hiroki Naka, Takeshi Nasu and Yoshiro Nogami
C 2022, 8(4), 70; https://doi.org/10.3390/c8040070 - 28 Nov 2022
Cited by 2 | Viewed by 1785
Abstract
Vertically aligned graphite substrate (VGS)-copper packaging was renowned for improving the robustness against the thermal gradient loading by using micro texturing. The micro-groove array with a line width of 50 μm and a pitch of 100 μm was formed into the VGS by [...] Read more.
Vertically aligned graphite substrate (VGS)-copper packaging was renowned for improving the robustness against the thermal gradient loading by using micro texturing. The micro-groove array with a line width of 50 μm and a pitch of 100 μm was formed into the VGS by controlling the line depth with the use of fast-rate oxygen plasma etching. Three micro-grooved VGS specimens were wet-plated to fill these microgrooves with copper deposits and to cover the VGS surfaces. The nearly full-deposited VGS-Copper specimens were subjected to a severe thermal transient loading test. The simply Cu-covered package and shallow rib-structured VGS-Cu packages were damaged to delaminate at their interfaces. The VGS-Cu package with the copper rib structure with a height of 50 μm experienced no delamination. This rib-structured VGS-copper package with high rib height had sufficient robustness against the severe thermal transients even with the proof of homogeneous thermal spreading capacity. Full article
(This article belongs to the Topic Application of Graphene-Based Materials)
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14 pages, 8451 KiB  
Article
Detonation Synthesis Nanodiamond Soot as a Promising Filler for Polymer Composites
by Oleg V. Lebedev, Tikhon S. Kurkin, Evgeny K. Golubev, Alexander L. Vasiliev, Andrey K. Gatin, Galina P. Goncharuk and Alexander N. Ozerin
C 2022, 8(4), 69; https://doi.org/10.3390/c8040069 - 27 Nov 2022
Cited by 3 | Viewed by 2283
Abstract
In this work, the results of a complex investigation of structure and properties of nanodiamond soot (NDS) of detonation synthesis are presented. Size distribution of NDS particles, dispersed in different liquid media, was investigated using dynamic light scattering and laser diffraction analysis methods. [...] Read more.
In this work, the results of a complex investigation of structure and properties of nanodiamond soot (NDS) of detonation synthesis are presented. Size distribution of NDS particles, dispersed in different liquid media, was investigated using dynamic light scattering and laser diffraction analysis methods. The results of the investigation, as well as the results of zeta-potential measurements, allowed us to characterize the agglomeration process of the NDS particles as independent of the medium, making NDS a good model filler for research of composite-modified nanosized particles. Additional data obtained using scanning electron microscopy, scanning tunneling microscopy, atomic force microscopy, X-ray diffraction, and Raman spectroscopy, demonstrated that in NDS the spherical nanodiamond (ND) particles with diameter ~5 nm are densely packed into strong-coupled aggregates with diameter ~300 nm, surrounded by graphite nanoribbons. X-ray diffraction analysis estimated the volume fraction of NDs in NDS as ~45 vol.%, simultaneously showing that the graphite is not defective, which was confirmed with the electron diffraction method. It was demonstrated that this structure of NDS allows to efficiently use NDS as a filler for polymer composites to increase polymer characteristics such as electrical conductivity or tribological characteristics, similarly to conventionally applied fillers such as carbon black. Full article
(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)
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19 pages, 7209 KiB  
Article
Easy Synthesis of Doped Graphitic Carbon Nitride Nanosheets as New Material for Enhanced DNA Extraction from Vegetal Tissues Using a Simple and Fast Protocol
by Manuel Eduardo Martínez-Cartagena, Juan Bernal-Martínez, Arnulfo Banda-Villanueva, Víctor D. Lechuga-Islas, Teresa Córdova, Ilse Magaña, José Román Torres-Lubián, Salvador Fernández-Tavizón, Jorge Romero-García, Ana Margarita Rodríguez-Hernández and Ramón Díaz-de-León
C 2022, 8(4), 68; https://doi.org/10.3390/c8040068 - 25 Nov 2022
Cited by 1 | Viewed by 2414
Abstract
Conventional and commercially available DNA extraction methods have several limitations regarding, for instance, contamination, and complex and slow precipitation and recovery processes. Herein, we report the synthesis of oxygen and phosphorus-doped Graphitic carbon nitride structures (g-POCN), via a novel Zinc-catalyzed one-pot solvothermal approach, [...] Read more.
Conventional and commercially available DNA extraction methods have several limitations regarding, for instance, contamination, and complex and slow precipitation and recovery processes. Herein, we report the synthesis of oxygen and phosphorus-doped Graphitic carbon nitride structures (g-POCN), via a novel Zinc-catalyzed one-pot solvothermal approach, and its application in the extraction of genomic DNA (gDNA) from a vegetal matrix (P. argentatum). Experimental and molecular modeling analyses demonstrate the high affinity of gDNA with g-POCN, which provided highly efficient gDNA extraction processes, with extraction yield, as well as integrity and quality of the extracted gDNA, comparable or superior to a commercial extraction kit and isopropanol extraction. Moreover, under suitable elution conditions, this method allows the easy removal of high concentrations of gDNA from g-POCN, rendering this method as a low-cost, simple, and fast approach for the extraction of even small amounts of gDNA. Remarkably, the extracted gDNA shows no degradation, and no inhibition of the polymerase chain reaction. Therefore, g-POCN represents a promising material for the highly efficient, cost-effective, and biocompatible extraction of DNA, which could stimulate research focused on broad DNA sources, e.g., RNA extraction, plasmids, ssDNA, etc. Full article
(This article belongs to the Special Issue Carbon-Based Catalyst (2nd Edition))
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15 pages, 1261 KiB  
Article
Assessing Soil Organic Carbon Stocks and Particle-Size Fractions across Cropping Systems in the Kiti Sub-Watershed in Central Benin
by Arcadius Martinien Agassin Ahogle, Felix Kouelo Alladassi, Tobi Moriaque Akplo, Hessou Anastase Azontonde and Pascal Houngnandan
C 2022, 8(4), 67; https://doi.org/10.3390/c8040067 - 23 Nov 2022
Cited by 5 | Viewed by 2790
Abstract
Soil organic carbon storage in agricultural soil constitutes a crucial potential for sustainable agricultural productivity and climate change mitigation. This paper aimed at assessing soil organic carbon stock and its distribution in three particle size fractions across five cropping systems located in Kiti [...] Read more.
Soil organic carbon storage in agricultural soil constitutes a crucial potential for sustainable agricultural productivity and climate change mitigation. This paper aimed at assessing soil organic carbon stock and its distribution in three particle size fractions across five cropping systems located in Kiti sub-watershed in Benin. Soil samples were collected using a grid sampling method on four soil depth layers: 0–10, 10–20, 20–30 and 30–40 cm in five cropping systems maize–cotton relay cropping (MCRC), yam–maize intercropping (YMI), teak plantation (TP), 5-year fallow (5YF) and above 10-year fallow (Ab10YF) from July to August 2017. Soil organic carbon stock (C stock) was estimated for the different soil layers and particle-size fractionation of soil organic matter was performed considering three fractions. The fractions coarse particulate organic matter (cPOM: 250–2000 µm), fine particulate organic matter (fPOM: 53–250 µm) and non-particulate organic matter (NOM: <53 µm) were separated from two soil depth layers: 0–10 and 10–20 cm. The results showed that fallow lands Ab10YF and 5YF exhibited the highest C stock, 22.20 and 17.74 Mg C·ha−1, while cultivated land under tillage MCRC depicted the lowest, C stock 11.48 Mg C·ha−1. The three organic carbon fractions showed a significant variation across the cropping systems with the NOM fraction holding the largest contribution to total soil organic carbon for all the cropping systems, ranging between 3.40 and 7.99 g/kg. The cPOM and fPOM were the most influenced by cropping systems with the highest concentration observed in Ab10YF and 5YF. The findings provide insights for upscaling farm management practices towards sustainable agricultural systems with substantial potential for carbon sequestration and climate change mitigation. Full article
(This article belongs to the Special Issue Biomass—a Renewable Resource for Carbon Materials)
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15 pages, 1079 KiB  
Article
Activated Carbon from Stipa tenacissima for the Adsorption of Atenolol
by Nesrine Madani, Imane Moulefera, Souad Boumad, Diego Cazorla-Amorós, Francisco José Varela Gandía, Ouiza Cherifi and Naima Bouchenafa-Saib
C 2022, 8(4), 66; https://doi.org/10.3390/c8040066 - 22 Nov 2022
Cited by 3 | Viewed by 2221
Abstract
The Stipa tenacissima S. is an endemic species of the Western Mediterranean countries, which grows on the semi-arid grounds of North Africa and South Spain. This biomass offers an abundant, renewable, and low-cost precursor for the production of activated carbon (AC). In that [...] Read more.
The Stipa tenacissima S. is an endemic species of the Western Mediterranean countries, which grows on the semi-arid grounds of North Africa and South Spain. This biomass offers an abundant, renewable, and low-cost precursor for the production of activated carbon (AC). In that context, ACs were prepared by chemical activation of Stipa tenacissima leaves (STL) using phosphoric acid (H3PO4). The effects of activation temperature and impregnation ratio on the textural and chemical surface properties of the prepared activated carbons were investigated. Activation temperatures of 450 and 500 °C turned out to be the most suitable to produce activated carbons with well-developed porous textures. The best results in terms of developed surface area (1503 m2/g) and micropore volume (0.59 cm3/g) were observed for an STLs to phosphoric acid ratio of 1:2 and a carbonization temperature of 450 °C. The adsorption capacity of the optimal activated carbon was found to be 110 mg/g for the atenolol drug. The adsorption equilibrium was well explained by the pseudo-second-order model and Langmuir isotherm. This study showed that the chemical activation method using H3PO4 as an activating agent was suitable for developing STL-based activated carbon prepared for the removal of atenolol drug in an aqueous solution and compared with commercial activated carbon supplied by Darco. Full article
(This article belongs to the Special Issue Biomass—a Renewable Resource for Carbon Materials)
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23 pages, 5569 KiB  
Review
Fabrication of Metal/Graphene Composites via Cold Spray Process: State-of-the-Art and the Way Forward
by Krishnamurthy Prasad, Rizwan Abdul Rahman Rashid, Novana Hutasoit, Suresh Palanisamy and Nishar Hameed
C 2022, 8(4), 65; https://doi.org/10.3390/c8040065 - 15 Nov 2022
Cited by 1 | Viewed by 3148
Abstract
Cold spray (CS)-fabricated metal–graphene composites have applications in several fields ranging from tribology and corrosion protection to antibacterial applications. However, it is critical from a process perspective to create a viable feedstock, and to this end, there are two widely reported techniques: ball [...] Read more.
Cold spray (CS)-fabricated metal–graphene composites have applications in several fields ranging from tribology and corrosion protection to antibacterial applications. However, it is critical from a process perspective to create a viable feedstock, and to this end, there are two widely reported techniques: ball milling and in situ reduction. In this paper, the CS feedstocks prepared via these two methods are compared and contrasted with other miscellaneous techniques in the literature based on their efficacies and the end properties of the fabricated coatings. CS metal–graphene composite coatings are found to display self-healing behaviour and excellent corrosion/wear resistance and mechanical properties, but at this juncture, there is a gap in the literature as far as the CS fabrication of self-standing metal–graphene composite parts is concerned. Several future research avenues are discussed to fully comprehend the printability and functionality of metal/GNP composite cold-sprayed structures. Full article
(This article belongs to the Collection Feature Papers in the Science and Engineering of Carbons)
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17 pages, 3865 KiB  
Article
Development of Carbon-Based Support Using Biochar from Guava Seeds for Lipase Immobilization
by Lays C. de Almeida, Felipe A. de Jesus, Flávia M. S. Wiltshire, Roberta M. Santos, Alini T. Fricks, Lisiane dos S. Freitas, Matheus M. Pereira, Álvaro S. Lima and Cleide M. F. Soares
C 2022, 8(4), 64; https://doi.org/10.3390/c8040064 - 14 Nov 2022
Cited by 2 | Viewed by 2272
Abstract
Enzymes are promising tools for achieving an environmentally benign process. However, enzymes are required to be immobilized on economically competent supports to be reusable and maintain their activity. In this work, the aim was to evaluate the application of the biochar for immobilization [...] Read more.
Enzymes are promising tools for achieving an environmentally benign process. However, enzymes are required to be immobilized on economically competent supports to be reusable and maintain their activity. In this work, the aim was to evaluate the application of the biochar for immobilization of Burkholderia cepacia lipase (BCL) by physical adsorption (PA) and covalent binding (CB). Additionally, it was observed that regarding the biochemical properties, the optimal pH was 4.0 for the BCL immobilized by PA and pH 7.0 for the BCL free and immobilized by CB. Among the kinetic parameters, the maximal velocity (Vmax) for the free enzyme was 2500 µmol g−1·min−1, and for the PA- and CB-immobilized biocatalyst the values of Vmax were 2000 and 3333 µmol g−1·min−1, respectively. The Michaelis-Menten constant (Km) value for the free lipase was 665 mM and for the biocatalysts immobilized by PA and CB the Km values were 219 and 369 mM, respectively. Immobilized LBC exhibited superior thermal stability. The reusability tests showed that the LBC immobilized by PA preserved 50% of the initial activity after 16 cycles. Thus, biochar is a by-product of a renewable source; therefore, it is a promising alternative for lipase immobilization demonstrating its potential for use in a wide range of greener industrial processes. Full article
(This article belongs to the Special Issue Carbon-Based Catalyst (2nd Edition))
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15 pages, 2834 KiB  
Article
Conversion of Coal-Biomass into Diesel by Using Aspen Plus
by Bilal Bashir, Muhammad Amin, Anaiz Gul Fareed and Zia Ur Rahman Farooqi
C 2022, 8(4), 63; https://doi.org/10.3390/c8040063 - 10 Nov 2022
Cited by 1 | Viewed by 3488
Abstract
Taking the importance of Pakistan’s dire need for energy breakthrough, in this paper, we explore how the country’s vast estimated reserves of 175 billion tons of Thar coal is a useful source for the clean and efficient production of good quality liquid fuel. [...] Read more.
Taking the importance of Pakistan’s dire need for energy breakthrough, in this paper, we explore how the country’s vast estimated reserves of 175 billion tons of Thar coal is a useful source for the clean and efficient production of good quality liquid fuel. Coal to liquid (CTL) technology has gathered increasing attention among many countries with a sufficient volume of coal reserves, and this technology can also be implemented in Pakistan, which in result can also reduce harmful greenhouse gas (GHG) emissions in the environment. In this study, the Fischer Tropsch Synthesis (FT) liquefaction method was used, and the reactor design, chemical reactions, syngas ratio fraction, and Anderson-Schulz-Flory and Langmuir model were all obtained from the Aspen Plus simulation. The results showed that, at the optimum syngas flow rate of 9 Kg/s, the FT model produced diesel fuel at 0.00134 Kg/s. Per this calculation, the massive amount of Thar coal reserves can be transformed into 123.22 million barrels of diesel. The design of the reactor is very critical, and, in this study, it was prioritized to design a reactor that produces liquid fuel only of composition C12+; during the production of liquid fuel, the quantity of methane is not high; and it can still be further reduced on optimized conditions. On the other hand, CO2 gas, which is a sole contributor of GHG emissions, was also reduced by up to 98%. Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection)
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10 pages, 7741 KiB  
Article
Tailoring the Properties of Ni(111)/Graphone Interfaces by Intercalation of Al and Na: A DFT Study
by Ramakrishnan Archana, Niharika Joshi and Thirumalaiswamy Raja
C 2022, 8(4), 62; https://doi.org/10.3390/c8040062 - 9 Nov 2022
Cited by 1 | Viewed by 1941
Abstract
With the incredible discovery of graphene (Gr), all of the properties studied to date suggest that it has promising applications in the development of semiconductor, spintronic, insulating, and polymer materials. However, efforts are still underway to fully understand the nature of metal–graphone(GrH) interaction [...] Read more.
With the incredible discovery of graphene (Gr), all of the properties studied to date suggest that it has promising applications in the development of semiconductor, spintronic, insulating, and polymer materials. However, efforts are still underway to fully understand the nature of metal–graphone(GrH) interaction in order to offer better scope for tuning the electronic and magnetic properties, which can be performed by intercalation of atoms via metal support on graphene. We chose metal atoms belonging to the s and p blocks, namely Na and Al, respectively, as the intercalating atoms. Herein, the maximum coverage of a monolayer of Na and Al was comparatively studied on a Ni(111) surface. Significant changes in the magnetic and electronic properties at the Ni(111)/graphone interface were observed upon intercalation. Of the two intercalating metal atoms, Na proved to be more effective, such that the magnetic properties of the surface Ni were only slightly decreased, and the graphone also showed better magnetic properties than in the absence of Na. Full article
(This article belongs to the Topic Application of Graphene-Based Materials)
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8 pages, 908 KiB  
Article
Polarizability of Kekulene, Septulene, and Nearest Non-Planar Polycyclic Aromatic Hydrocarbons
by Timur Lukmanov, Arslan F. Akhmetov and Denis Sh. Sabirov
C 2022, 8(4), 61; https://doi.org/10.3390/c8040061 - 7 Nov 2022
Cited by 3 | Viewed by 2150
Abstract
The polarizability of polycyclic aromatic hydrocarbons (PAHs) is an important property that relates to their abundance in natural environments. To assess the differences in the mean polarizability of planar and non-planar polycyclic aromatic hydrocarbons (PAHs), we computationally studied the PAH series of circulenes [...] Read more.
The polarizability of polycyclic aromatic hydrocarbons (PAHs) is an important property that relates to their abundance in natural environments. To assess the differences in the mean polarizability of planar and non-planar polycyclic aromatic hydrocarbons (PAHs), we computationally studied the PAH series of circulenes (kekulene C48H24, [13]circulene C52H26, and septulene C56H28), a number of the nearest helicenes, and their “expanded” isomers. We mean under “nearest” a close number of aromatic rings: 11 (C46H26), 12 (C50H28), 13 (C54H30), and 14 (C58H32). For these PAHs, we performed the quantum chemical calculations of thermodynamic and polarizability parameters with the PBE/3ζ density functional theory method, which is widely used in the theoretical chemistry of fullerenes and PAHs. The calculated mean polarizabilities (in Å3) ranged from 80.1 for [11]helicene to 135.5 for septulene, and while the circulenes and expanded helicenes had similar values, the mean polarizability of the normal helicenes was markedly lower. In all four pairs of helical PAHs, the expanded helicene was energetically considerably more favorable than its standard helicene isomer. Herewith, the ratio of their polarizabilities was equal to 1.3. Full article
(This article belongs to the Section Carbon Skeleton)
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11 pages, 4173 KiB  
Article
Conducting Polymer Metallic Emerald: Magnetic Measurements of Nanocarbons/Polyaniline and Preparation of Plastic Composites
by Yusuke Koshikawa, Ryo Miyashita, Takuya Yonehara, Kyoka Komaba, Reiji Kumai and Hiromasa Goto
C 2022, 8(4), 60; https://doi.org/10.3390/c8040060 - 4 Nov 2022
Viewed by 2002
Abstract
Synthesis of polyaniline in the presence of fullerene nanotubes (nanocarbons) in water was carried out with oxidative polymerization. The surface of the sample showed metallic emerald green color in bulk like the brilliance of encrusted gemstones. The composite showed unique magnetic behavior, such [...] Read more.
Synthesis of polyaniline in the presence of fullerene nanotubes (nanocarbons) in water was carried out with oxidative polymerization. The surface of the sample showed metallic emerald green color in bulk like the brilliance of encrusted gemstones. The composite showed unique magnetic behavior, such as microwave power-dependent magnetic resonance as magnetic spin behavior and macroscopic paramagnetism with a maximum χ value at room temperature evaluated with superconductor interference device. Surface structure of the composite was observed with optical microscopy, circular polarized differential interference contrast optical microscopy, scanning electron microscopy, and electron probe micro analyzer. Polymer blends consisting of polyaniline, nano-carbons, and hydroxypropylcellulose or acryl resin with both conducting polymer and carbon characters were prepared, which can be applied for electrical conducting plastics. The combination of conducting polymer and nano-carbon materials can produce new electro-magneto-active soft materials by forming a composite. This paper reports evaluation of magnetic properties as a new point of nanocarbon and conducting polymer composite. Full article
(This article belongs to the Special Issue Carbon-Based Catalyst (2nd Edition))
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27 pages, 2922 KiB  
Article
Applicability and Limitations of Ru’s Formulation for Vibration Modelling of Double-Walled Carbon Nanotubes
by Matteo Strozzi
C 2022, 8(4), 59; https://doi.org/10.3390/c8040059 - 2 Nov 2022
Cited by 2 | Viewed by 1866
Abstract
In this paper, a comparison is conducted between two different formulations of the van der Waals interaction coefficient between layers, as applied to the vibrations of double-walled carbon nanotubes (DWCNTs); specifically, the evaluation of the natural frequencies is achieved through Ru’s and He’s [...] Read more.
In this paper, a comparison is conducted between two different formulations of the van der Waals interaction coefficient between layers, as applied to the vibrations of double-walled carbon nanotubes (DWCNTs); specifically, the evaluation of the natural frequencies is achieved through Ru’s and He’s formulations. The actual discrete DWCNT is modelled by means of a couple of concentric equivalent continuous thin cylindrical shells, where Donnell shell theory is adopted to obtain strain-displacement relationships. In order to take into account the chirality effect of DWCNT, an anisotropic elastic shell model is considered. Simply supported boundary conditions are imposed and the Rayleigh–Ritz method is used to obtain approximate natural frequencies and mode shapes. A parametric analysis considering different values of diameters and numbers of waves along longitudinal and circumferential directions is performed by adopting Ru’s and He’s formulations. From the comparisons, it is evident that Ru’s formulation provides unsatisfactory results for relatively low values of diameters and relatively high numbers of circumferential waves with respect to the more accurate He’s formulation. This behaviour is observed for every number of longitudinal half-waves. Therefore, Ru’s formulation cannot be used for the vibration modelling of DWCNTs in a large range of diameters and wavenumbers. Full article
(This article belongs to the Collection Novel Applications of Carbon Nanotube-Based Materials)
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9 pages, 1530 KiB  
Article
Lauric Acid Treatments to Oxidized and Control Biochars and Their Effects on Rubber Composite Tensile Properties
by Steven C. Peterson and A. J. Thomas
C 2022, 8(4), 58; https://doi.org/10.3390/c8040058 - 29 Oct 2022
Cited by 2 | Viewed by 1890
Abstract
Biochar is a renewable source of carbon that can partially replace carbon black as filler in rubber composites. Since the carbon content of biochar is less pure than carbon black, improvements and modifications must be made to biochar to make it a viable [...] Read more.
Biochar is a renewable source of carbon that can partially replace carbon black as filler in rubber composites. Since the carbon content of biochar is less pure than carbon black, improvements and modifications must be made to biochar to make it a viable co-filler. In this work, two methods to change the surface chemistry of biochar were employed: (1) gas treatment at 300 °C with either air or carbon dioxide, and (2) coating with lauric acid. Both methods are amenable to the current rubber processing industry. After biochar was treated with these methods, it was used as co-filler in rubber composite samples. Gas treatment with either air or carbon dioxide was found to increase stiffness in the final composites. Although lauric acid coating of biochar by itself did not have a significant effect on tensile properties, biochar that was first treated with carbon dioxide and then coated with lauric acid showed a 19% increase in tensile strength and a 48% increase in toughness. Gas treatment and lauric acid coating of biochar provide relatively simple processing techniques to improve the stiffness and tensile strength of biochar as rubber composite filler. Full article
(This article belongs to the Special Issue Biomass—a Renewable Resource for Carbon Materials)
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13 pages, 4167 KiB  
Article
Effect of Absorption Time for the Preparation of Activated Carbon from Wasted Tree Leaves of Quercus alba and Investigating Life Cycle Assessment
by Muhammad Amin and Hamad Hussain Shah
C 2022, 8(4), 57; https://doi.org/10.3390/c8040057 - 28 Oct 2022
Cited by 13 | Viewed by 2543
Abstract
In this article, the effect of absorption time on the surface chemistry and pore structure of activated carbon (AC) from waste leaves of Quercus alba with the H3PO4 chemical activation method. XRD, SEM, EDX, BET, TGA, and FT-IR analyses of [...] Read more.
In this article, the effect of absorption time on the surface chemistry and pore structure of activated carbon (AC) from waste leaves of Quercus alba with the H3PO4 chemical activation method. XRD, SEM, EDX, BET, TGA, and FT-IR analyses of prepared AC were used to figure out the properties of the activated carbon. The results demonstrated that the 48 h absorption time of H3PO4 contributed to the highest surface area, 943.2 m2/g, among all the prepared activated carbon samples. As the absorption time of the phosphoric acid activating agent was increased, the surface area initially increased and then started to decrease. The further surface chemical characterization of activated carbon was determined by FT-IR spectroscopic method. Life cycle assessment methodology was employed in order to investigate the environmental impacts associated with the laboratory steps for activated carbon (AC) production. The LCA approach was implemented using OpenLCA 1.10.3 software, while ReCiPe Midpoint (H) was used for environmental impact assessment. The results of the LCA study showed that the impact categories related to toxicity were particularly affected by the utilization of electrical energy (≈90%). The power utilized during laboratory procedures was the main cause of environmental impacts, contributing an average of nearly 70% across all impact categories, with the maximum contribution to the impact category of freshwater ecotoxicity potential (≈97%) and the minimum contribution to land use potential (≈10%). Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection)
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19 pages, 5652 KiB  
Review
3D Cell Spheroids as a Tool for Evaluating the Effectiveness of Carbon Nanotubes as a Drug Delivery and Photothermal Therapy Agents
by Roman A. Anisimov, Dmitry A. Gorin and Anatolii A. Abalymov
C 2022, 8(4), 56; https://doi.org/10.3390/c8040056 - 27 Oct 2022
Cited by 10 | Viewed by 3502
Abstract
Cell spheroids (CSs) are three-dimensional models in vitro that have a microenvironment similar to tissues. Such three-dimensional cellular structures are of great interest in the field of nano biomedical research, as they can simulate information about the characteristics of nanoparticles (NPs) by avoiding [...] Read more.
Cell spheroids (CSs) are three-dimensional models in vitro that have a microenvironment similar to tissues. Such three-dimensional cellular structures are of great interest in the field of nano biomedical research, as they can simulate information about the characteristics of nanoparticles (NPs) by avoiding the use of laboratory animals. Due to the development of areas such as bioethics and tissue engineering, it is expected that the use of such 3D cell structures will become an even more valuable tool in the hands of researchers. We present an overview of carbon nanotubes (CNTs) research on CSs in order to determine the mechanism of their incorporation into CSs, drug delivery, and photothermal therapy. We will look at such areas as the application of CNTs for medical purposes, the advantages of spheroids over classical 2D cell culture, the ways in which CNTs pass into the intercellular space, and the ways in which they are absorbed by cells in a three-dimensional environment, the use of the spheroid model for such studies as drug delivery and photothermal therapy. Thus, CSs are suitable models for obtaining additional information on the required properties of CNTs in their application in nanobiomedicine. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)
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19 pages, 5823 KiB  
Review
Rice-Husk-Based Materials for Biotechnological and Medical Applications
by Gaukhar Smagulova, Aigerim Imash, Akniyet Baltabay, Bayan Kaidar and Zulkhair Mansurov
C 2022, 8(4), 55; https://doi.org/10.3390/c8040055 - 27 Oct 2022
Cited by 6 | Viewed by 5681
Abstract
This review contains the main research directions, which are directly aimed at converting materials based on rice husks particularly, for their role for medicine and biotechnology. Especially in developing countries, more than 95% of rice husks are produced. Although numerous studies have been [...] Read more.
This review contains the main research directions, which are directly aimed at converting materials based on rice husks particularly, for their role for medicine and biotechnology. Especially in developing countries, more than 95% of rice husks are produced. Although numerous studies have been conducted on the production of various materials from rice husks, the existing scientific information is still widely scattered in the literature. Therefore, this review article provides extensive information on the work of various researchers, including the Institute of Combustion Problems (Almaty, Kazakhstan), on the production of various materials from rice husks and their physico-chemical characteristics. The main applications of rice husk materials in medicine are discussed. The ways of prospective conversion of rice husks for biotechnological purposes are considered. Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection)
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13 pages, 2203 KiB  
Article
Carbon Dots versus Nano-Carbon/Organic Hybrids—Divergence between Optical Properties and Photoinduced Antimicrobial Activities
by Audrey F. Adcock, Ping Wang, Elton Y. Cao, Lin Ge, Yongan Tang, Isaiah S. Ferguson, Fares S. Abu Sweilem, Lauren Petta, William Cannon, Liju Yang, Christopher E. Bunker and Ya-Ping Sun
C 2022, 8(4), 54; https://doi.org/10.3390/c8040054 - 20 Oct 2022
Cited by 3 | Viewed by 3120
Abstract
Carbon dots (CDots) are generally defined as small-carbon nanoparticles with surface organic functionalization and their classical synthesis is literally the functionalization of preexisting carbon nanoparticles. Other than these “classically defined CDots”, however, the majority of the dot samples reported in the literature were [...] Read more.
Carbon dots (CDots) are generally defined as small-carbon nanoparticles with surface organic functionalization and their classical synthesis is literally the functionalization of preexisting carbon nanoparticles. Other than these “classically defined CDots”, however, the majority of the dot samples reported in the literature were prepared by thermal carbonization of organic precursors in mostly “one-pot” processing. In this work, thermal processing of the selected precursors intended for carbonization was performed with conditions of 200 °C for 3 h, 330 °C for 6 h, and heating by microwave irradiation, yielding samples denoted as CS200, CS330, and CSMT, respectively. These samples are structurally different from the classical CDots and should be considered as “nano-carbon/organic hybrids”. Their optical spectroscopic properties were found comparable to those of the classical CDots, but very different in the related photoinduced antibacterial activities. Mechanistic origins of the divergence were explored, with the results suggesting major factors associated with the structural and morphological characteristics of the hybrids. Full article
(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application)
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13 pages, 1585 KiB  
Article
Use of Heteroatom-Doped g-C3N4 Particles as Catalysts for Dehydrogenation of Sodium Borohydride in Methanol
by Sahin Demirci and Nurettin Sahiner
C 2022, 8(4), 53; https://doi.org/10.3390/c8040053 - 16 Oct 2022
Cited by 9 | Viewed by 2877
Abstract
Here, graphitic carbon nitride (g-C3N4) was synthesized from melamine, doped with heteroatoms, such as B, S, and P reported using boric acid, sulfur, and phosphorous red as dopants, respectively. The catalytic performances of g-C3N4, and [...] Read more.
Here, graphitic carbon nitride (g-C3N4) was synthesized from melamine, doped with heteroatoms, such as B, S, and P reported using boric acid, sulfur, and phosphorous red as dopants, respectively. The catalytic performances of g-C3N4, and heteroatom-doped g-C3N4 (H@g-C3N4 (H=B, S or P) particles as catalysts in the dehydrogenation of sodium borohydride (NaBH4) in methanol to generate hydrogen (H2) were investigated. The prepared g-C3N4-based structures were used as catalysts for hydrogen (H2) production in the dehydrogenation reaction of sodium borohydride (NaBH4) in methanol. The catalytic performance of H@g-C3N4 (H=B, S or P) structures in the dehydrogenation reaction of sodium borohydride (NaBH4) in methanol was determined to be higher than the catalytic performance of the bare g-C3N4 structure. The hydrogen generation rate (HGR) values were calculated for the reactions catalyzed by B@g-C3N4, P@g-C3N4, and S@g-C3N4 as 609 ± 48, 699 ± 48, and 429 ± 55 mL H2/g of cat.min, respectively, which is only 282 ± 11 mL H2/g of cat.min for the native g-C3N4-catalyzed one. The activation energies (Ea) were found to be relatively low, such as 31.2, 26.9, and 31.2 kJ/mol, for the reactions catalyzed by B@g-C3N4, P@g-C3N4, and S@g-C3N4, respectively. In addition, in the reuse studies, it was concluded that B@g-C3N4, P@g-C3N4, and S@g-C3N4 catalysts can readily complete the reaction with 100% conversion, even in five consecutive uses, and afforded promising potential with more than 80% activity for each use. Full article
(This article belongs to the Special Issue Carbon-Based Catalyst (2nd Edition))
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2 pages, 1001 KiB  
Correction
Correction: Radtke et al. Plasma Treatments and Light Extraction from Fluorinated CVD-Grown (400) Single Crystal Diamond Nanopillars. C 2020, 6, 37
by Mariusz Radtke, Abdallah Slablab, Sandra Van Vlierberghe, Chao-Nan Lin, Ying-Jie Lu and Chong-Xin Shan
C 2022, 8(4), 52; https://doi.org/10.3390/c8040052 - 12 Oct 2022
Viewed by 1291
Abstract
The authors would like to update the XPS spectrum in Figure 3c [...] Full article
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