Добірка наукової літератури з теми "Biocarbon catalysts"

Biocarbon (BC) supported iron–cobalt–nickel (Fe–Co–Ni/BC) nanoalloy catalysts were synthesized by ultrasonic-assisted chemical reduction method. The morphological and physico-chemical characteristics show that the 1:1:1 composition of Fe–Co–Ni/BC catalyst has the Fe face-centered cubic (fcc) solid-solution structure showing the incorporation of Co and Ni. The electrocatalytic execution of this iron-based nanoalloy catalyst and its interaction with biocarbon was explored in a membraneless fuel cell and compared with carbon supported Fe–Co–Ni catalyst (Fe–Co–Ni/C). In a single-cell test, the power density obtained for Fe–Co–Ni/BC (35.4 mW/cm2) was better than that of Fe–Co–Ni/C (31.3 mW/cm2), utilizing 0.1 mol/L sodium perborate as oxidant and 1 mol/L ethylene glycol as fuel in an alkaline medium. The electrochemical findings revealed that the execution and solidness of the Fe–Co–Ni/BC catalyst is good and prevalent to that of Fe–Co–Ni/C catalyst. The better execution of BC-supported catalyst is due to its high electrical conductivity, high porosity and expansive surface area. It is been concluded that both the advantageous impact and the nature of support have an imperative part on the execution of Fe–Co–Ni/BC nanoalloy catalysts for the CO2-free ethylene glycol oxidation. Subsequently, it is accepted that the BC-supported Fe–Co–Ni nanoalloy catalysts are anticipated to be broadly utilized in electrocatalytic energy-conversion applications.

The overuse of non-renewables resources in the last decades has generated negative consequences for the society, which have boosting the search for mitigating the damage caused in the environment. Aiming to contribute to the expansion of the strategies to control the pollutants in the environment thought the development of low-cost technologies, the mean goal of present work is to develop active materials with high thermic resistance and suitable specific area to adsorption and impregnation of metals. In this regard, it was studied three different routes of treatment of the biocarbons. The biocarbons materials were characterized by infrared spectroscopy (IR), Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TG), and Brunauer–Emmett–Teller analysis (BET). The three different strategies of treatment resulted in changes in the carbonaceous structure of the biocarbon, resulting in suitable characteristics for support material for catalysts, such as activities sites with negative charge to promote the attachment of the metals on the carbon surface. It was also observed the enhancement of the specific surface area, that ranges from 341.4 to 749.7 m2 g-1, changes of D and G band of carbon and high temperature resistance, which promote catalytic reactions with catalyst loss.

Thermochemical conversion of lignocellulosic biomass is considered as a good opportunity to obtain liquid raw materials for biofuels and biochemicals. During this pyrolysis process a solid product, biocarbon, is obtained. Nowadays there is a growing interest in biocarbon, due to the potential benefits of its application in soil as a stimulant and CO2 trap. The physicochemical and porous properties of biocarbon are suitable for development of effective and inexpensive sorbents for the removal of contaminants from water. Biocarbon has promising sorption properties for various pollutants in water, including polycyclic aromatic hydrocarbons and heavy metals. Banana and orange peels, as well as cocoa flakes, were used as precursors. The carbonization was carried out at temperatures from 500 ° C to 900 ° C. Some of the samples were subjected to physical and chemical activation. The obtained carbon adsorbents are characterized by adsorption of iodine, BET, etc. It is planned to study the possibilities for the successful application of the obtained carbon materials as adsorbents for water and air purification, catalysts, hydrogen depots, etc.

Waste soybean hulls (WSH) were investigated as a Fe-support in two forms: raw and carbonized (i.e. biocarbon, BC), as possible value-added materials. Fe-impregnation was implemented in order to produce heterogeneous Fenton catalysts for Reactive Blue 4 dye degradation. Materials characterization demonstrated a rise in the specific surface area due to decomposition of WSH constituents during carbonization (to obtain BC) and thermal activation (to obtain Fe-WSH and Fe-BC), thus producing catalysts with high mesoporosity and hematite as the active site for Fenton reaction. Among the investigated materials, Fe-WSH showed the greatest ability for ?OH production in acidic medium. Next, the hetero-geneous Fenton process was optimized by using response surface methodology, which resulted in selection of the following reaction conditions: 3 mM H2O2, 100 mg Fe-WSH, reaction time of 180 min, at a constant pH 3, RB4 concentration of 50 mg dm-3 and at room temperature. The achieved dye removal and mineralization were 85.7 and 66.8 %, respecti-vely, while the catalyst showed high stability and the reaction intermediates formed during the oxidation process had a low inhibitory effect on Vibrio fischeri bacteria.

Currently, the development of nonmetallic oxygen reduction reaction (ORR) catalysts based on heteroatomic-doped carbon materials is receiving increaseing attention in the field of fuel cells. Here, we used enzymolytic lignin (EL), melamine, and thiourea as carbon, nitrogen, and sulfur sources and NH4Cl as an activator to prepare N- and S-codoped lignin-based polyporous carbon (ELC) by one-step pyrolysis. The prepared lignin-derived biocarbon material (ELC-1-900) possessed a high specific surface area (844 m2 g−1), abundant mesoporous structure, and a large pore volume (0.587 cm3 g−1). The XPS results showed that ELC-1-900 was successfully doped with N and S. ELC-1-900 exhibited extremely high activity and stability in alkaline media for the ORR, with a half-wave potential (E1/2 = 0.88 V) and starting potential (Eonset = 0.98 V) superior to those of Pt/C catalysts and most non-noble-metal catalysts reported in recent studies. In addition, ELC-1-900 showed better ORR stability and methanol tolerance in alkaline media than commercial Pt/C catalysts.

In this work, electroactive biofilms of Bacillus subtilis (B. subtilis) or Escherichia coli (E. coli) were supported on functionalized biocarbon (AB7-F), which was synthesized from waste leather and was used as catalysts to develop bioanodes for microbial fuel cells (MFCs). This way, bioanodes were fabricated and further evaluated in a three-electrode cell using pharmaceutical wastewater (PWW) as substrate. The electrochemical measurements showed a higher performance of the bioanode based on AB7-f+ B. subtilis to oxidize organic matter from PWW. The polarization curves in the dual-chamber MFC showed that AB7-f+ B. subtilis bioanode can generate an open circuit voltage of 602 mV and a power density of 77 mW m−2. During long-term tests of the MFC, a variation in performance was observed, with a maximum of 96.3 mW m−2 on day 7. Such variation was attributed to the development of more stable biofilm as well as consumption of some compounds metabolized by bacteria grown on the bioanode. The results showed that AB7-f+ B. subtilis can be used as bioanode for MFCs with PWW as substrate removing around 45% of the chemical oxygen demand (COD).

Novel SB@α-Fe₂O₃ composite catalysts were fabricated through a simple thermal conversion process from SB@β-FeOOH precursor, which maintained good adsorption capacity after five successive adsorption/heterogeneous Fenton-like regeneration cycles.

Water pollution ranging from harmful chemical substances to pathogenic bacteria is a growing problem from industry to society as a whole[1-2].There is a need to find new, cost-effective sustainable materials with high efficacy to clean up water and to protect the environment. Biocarbon (BC), a material with high specific surface area and large porosity, has some potential for removing water pollutants, but it also has many limitations. However, biocarbon-based composites can be tailored and may have a greater potential for removing contaminants in water. ZnO biochar and TiO2 biochar nanocomposites have been shown to effectively remove harmful chemical substances, such as industrial dyes, and additionally kill potential pathogenic bacteria[2–8]. In this project, we combined TiO2 and ZnO with biochar to create an active nanocomposite surface to see if this could be a cost-effective method to deactivate bacteria and degrade specific dyes. We present the fabrication and examination of TiO2/biochar (BC) and ZnO/BC composite photocatalysts, synthesized via hydrolysis technique. These catalysts were designed for the purpose of methyl orange (MO) degradation and bacterial strain inactivation. A comprehensive assessment of these catalysts was carried out using a number of sophisticated methods, including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis spectrophotometry for evaluation of degradation. Moreover, the direct contact method was used for antibacterial analysis. Our findings underline the exceptional properties of these composites for water decontamination and antibacterial efficacy. The nanocomposites showed remarkable photocatalytic performance in MO removal from wastewater, achieving a superior removal efficiency of 92%, as shown in Figure 1. This can be attributed to their outstanding electron transfer efficacy. In addition, the TiO2/BC and ZnO/BC nanocomposites manifested robust antibacterial properties, and they showed an antibacterial effectiveness of 85% against Escherichia coli (E. coli) (Table 1). This research highlights the promising potential of TiO2/BC and ZnO/BC nanocomposites as eco-friendly and multifaceted materials, suggesting a wide range of potential applications in water purification and antibacterial activity. Acknowledgments: The authors acknowledge the research grants from project # 6000237-13 Figure: Figure 1. Photocatalytic degradation of MO (initial concentration; 20 mg/L) under solar light irradiation, a) Pure BC and TiO2, and composite TiO2/BC catalysts, b) Pure BC and ZnO, and ZnO/BC catalysts. Table: Table 1. Antimicrobial efficiency of 5 different catalysts against E. coli. References [1] A. S. Eltaweil, I. M. Mamdouh, E. M. Abd El-Monaem, and G. M. El-Subruiti, “Highly Efficient Removal for Methylene Blue and Cu2+onto UiO-66 Metal-Organic Framework/Carboxylated Graphene Oxide-Incorporated Sodium Alginate Beads,” ACS Omega, 2021, doi: 10.1021/acsomega.1c03479. [2] J. Hidalgo-Jimenez et al., “Phase transformations, vacancy formation and variations of optical and photocatalytic properties in TiO2-ZnO composites by high-pressure torsion,” Int J Plast, vol. 124, pp. 170–185, Jan. 2020, doi: 10.1016/j.ijplas.2019.08.010. [3] A. S. Eltaweil, A. M. Abdelfatah, M. Hosny, and M. Fawzy, “Novel Biogenic Synthesis of a Ag@Biochar Nanocomposite as an Antimicrobial Agent and Photocatalyst for Methylene Blue Degradation,” ACS Omega, vol. 7, no. 9, pp. 8046–8059, Mar. 2022, doi: 10.1021/acsomega.1c07209. [4] S. Riaz and S. J. Park, “An overview of TiO2-based photocatalytic membrane reactors for water and wastewater treatments,” Journal of Industrial and Engineering Chemistry, vol. 84. Korean Society of Industrial Engineering Chemistry, pp. 23–41, Apr. 25, 2020. doi: 10.1016/j.jiec.2019.12.021. [5] L. Lu, R. Shan, Y. Shi, S. Wang, and H. Yuan, “A novel TiO2/biochar composite catalysts for photocatalytic degradation of methyl orange,” Chemosphere, vol. 222, pp. 391–398, May 2019, doi: 10.1016/j.chemosphere.2019.01.132. [6] R. Zha, R. Nadimicherla, and X. Guo, “Ultraviolet photocatalytic degradation of methyl orange by nanostructured TiO2/ZnO heterojunctions,” J Mater Chem A Mater, vol. 3, no. 12, pp. 6565–6574, Mar. 2015, doi: 10.1039/c5ta00764j. [7] J. Liu et al., “Preparation, environmental application and prospect of biochar-supported metal nanoparticles: A review,” Journal of Hazardous Materials, vol. 388. Elsevier B.V., Apr. 15, 2020. doi: 10.1016/j.jhazmat.2020.122026. [8] J. Liu et al., “Preparation, environmental application and prospect of biochar-supported metal nanoparticles: A review,” Journal of Hazardous Materials, vol. 388. Elsevier B.V., Apr. 15, 2020. doi: 10.1016/j.jhazmat.2020.122026. Figure 1

Biocarbons were obtained by physical and chemical activation of the residue of the extraction of chaga fungi (Inonotus obliquus). The residue was subjected to heat treatment carried out in a microwave oven and in a quartz tubular reactor. The materials were characterized by elemental analysis, low-temperature nitrogen adsorption, determination of pH, and the contents of acidic and basic oxygen functional groups on the surface of biocarbons by the Boehm method. The final biocarbon adsorbents have surface areas varying from 521–1004 m2/g. The physical activation of the precursor led to a strongly basic character of the surface. Chemical activation of Inonotus obliquus promoted the generation of acid functional groups. All biocarbons were used for methyl red sodium salt adsorption from the liquid phase. The sorption capacities of biocarbons towards the organic dye studied varied from 77 to 158 mg/g. The Langmuir model was found to better describe the experimental results. The results of the kinetic analysis showed that the adsorption of methyl red sodium salt on the biocarbons followed the pseudo-second-order model. The acidic environment was conducive to the adsorption of the dye on the obtained biocarbons. Moreover, thermodynamic studies confirmed that the organic dye adsorption on the biocarbons was a spontaneous endothermic process. The biocarbons obtained were also tested as adsorbents of hydrogen sulfide in dry and wet conditions. The sorption capacities towards hydrogen sulfide varied in the range of 21.9–77.9 mg. The results have shown that the adsorption of hydrogen sulfide depends on the process conditions and the activation procedure of biocarbons (method of activation and thermochemical treatment of samples). It has been shown that the initial material used can be a new precursor for obtaining cheap and—more importantly—universal bioadsorbents characterized by high effectiveness in the removal of air and water pollutants.

Ce travail propose une approche innovante pour la production, caractérisation et utilisation de catalyseurs biosourcés pour des applications dans les domaines de l'énergie et de l'environnement, afin de réduire le coût et l'impact des catalyseurs commerciaux actuellement utilisés. Le travail développé ici promeut une approche d'économie circulaire dans la mesure où des plantes issues de la phytoremédiation ont été employées pour la production de catalyseurs biosourcés, respectueux de l'environnement. Ces catalyseurs ont été utilisés pour produire des vecteurs énergétiques tels que l'hydrogène à partir des réactions de gaz à l'eau direct (water-gas shift, WGS) et indirect (reverse water-gas shift, RWGS), et pour la décomposition des polluants de NOx (deNOx). Les catalyseurs biosourcés ont été produits à partir de saule et fougère avec un contenu contrôlé en métaux introduit par imprégnation avant ou après pyrolyse à 800°C afin d'imiter l'hyperaccumulation (>3 g métal /kg biocarbone) dans un support carboné poreux. Les catalyseurs ainsi produits ont été testés pour les réactions de deNOx, ainsi que dans WGS et RWGS, et les dispositifs expérimentaux associés ont été développés et optimisés pendant la thèse. Ils ont été caractérisés en termes de composition, structure et stabilité thermique, ceci avant et après utilisation. Pour les trois réactions, les catalyseurs ont montré une sélectivité et une conversion élevées et maintenues dans les conditions de réaction, facilitées par le contenu en métaux catalytiques dont l'activité a été renforcée par les métaux inhérents. La présence de fonctions oxygénées de surface et d'une surface spécifique élevée (<419 m²/g) ont amélioré l'adsorption et la dissociation des gaz réactifs grâce à des sites supplémentaires formés par réduction et à une meilleure activité électronique. Avec ces caractéristiques, les catalyseurs biosourcés ont montré des performances meilleures que celles de catalyseurs références de la littérature en raison d'une meilleure stabilité ou activité catalytiques (conversion maintenue pour plus de 120h, énergie d'activation entre 0.5 et 186 kJ/mol, constante cinétique entre 1.9 x 10^-9 et 4.3 x 10^12. Le catalyseur de saule imprégné au Ni avant pyrolyse et le catalyseur bimétallique (Ni/Fe) de fougère ont montré les meilleures performances pour les réactions de deNOx, et RWGS et WGS, respectivement
This work proposes an innovative approach to the production, characterization and use of biocarbon catalysts for energy and environment-related applications, in order to reduce the cost and impact of the commercial catalysts currently in use. The work developed here promotes a circular economy approach in the way that plants from phytoremediation have been used for the production of eco-friendly biocarbon catalysts. They were used for the production of energy vectors such as hydrogen by direct and reverse water-gas shift reaction (WGS and RWGS respectively), as well as for the decomposition of NOx pollutants (deNOx). Biocarbon catalysts were produced from willow and fern with a controlled metal content introduced by wet impregnation before or after pyrolysis at 800°C to imitate hyperaccumulation (>3 g metal/kg biocarbon) in a porous carbon support. The resulting catalysts were tested in deNOx, as well as WGS and RWGS reactions, and the associated experimental equipments were developed and optimized during this thesis work. They were characterized in terms of composition, structure and thermal stability, before and after use. For the three reactions, the catalysts showed high selectivity and conversion, facilitated by the catalytic metals whose activity was enhanced by the inherent metals. The presence of surface oxygen functions and a high specific surface area (<419 m²/g) improved adsorption and dissociation of reactive gases thanks to additional reactive sites formed by reduction and enhanced electronic activity. With these characteristics, biocarbon catalysts showed better performances than literature-based reference catalysts as they were either more stable or active (conversion maintained for more than 120h, activation energy from 0.5 to 186 kJ/mol, kinetic constant between 1.9 x 10^-9 and 4.3 x 10^12). Willow biocarbon impregnated with Ni before pyrolysis and bimetallic (Ni/Fe) fern biocarbon showed the best performances for the deNOx, and RWGS and WGS reactions, respectively