High-temperature Pyrolysis Research Articles

Bifunctional Electrocatalyst Derived by High-Temperature Pyrolysis of 3-Amino-1,2,4-Triazole-Modified Fe-ZIF Nanostructures for Oxygen Reduction and Evolution Reactions

Bifunctional Electrocatalyst Derived by High-Temperature Pyrolysis of 3-Amino-1,2,4-Triazole-Modified Fe-ZIF Nanostructures for Oxygen Reduction and Evolution Reactions

Fractionation and Lability of Phosphorus Species in Cottonseed Meal-Derived Biochars as Influenced by Pyrolysis Temperature.

Defatted cottonseed meal (CSM), the residue of cottonseeds after oil extraction, is a major byproduct of the cotton industry. Converting CSM to biochar and utilizing the goods in agricultural and environmental applications may be a value-added, sustainable approach to recycling this byproduct. In this study, raw CSM was transformed into biochar via complete batch slow pyrolysis at 300, 350, 400, 450, 500, 550, and 600 °C. Thermochemical transformation of phosphorus (P) in CSM during pyrolysis was explored. Fractionation, lability, and potential bioavailability of total P (TP) in CSM-derived biochars were evaluated using sequential and batch chemical extraction techniques. The recovery of feed P in biochar was nearly 100% at ≤550 °C and was reduced to <88% at 600 °C. During pyrolysis, the organic P (OP) molecules predominant in CSM were transformed into inorganic P (IP) forms, first to polyphosphates and subsequently to orthophosphates as promoted by a higher pyrolysis temperature. Conversion to biochar greatly reduced the mobility, lability, and bioavailability of TP in CSM. The biochar TP consisted of 9.3-17.9% of readily labile (water-extractable) P, 10.3-24.1% of generally labile (sequentially NaHCO3-extractable) P, 0.5-2.8% of moderately labile (sequentially NaOH-extractable) P, 17.0-53.8% of low labile (sequentially HCl-extractable) P, and 17.8-47.5% of residual (unextractable) P. Mehlich-3 and 1 M HCl were effective batch extraction reagents for estimating the "readily to mid-term" available and the "overall" available P pools of CSM-derived biochars, respectively. The biochar generated at 450 °C exhibited the lowest proportions of readily labile P and residual P compounds, suggesting 450 °C as the optimal pyrolysis temperature to convert CSM to biochar with maximal P bioavailability and minimal runoff risk.

Preparation and investigation of high-efficiency ZIF-67/MoS2-based microwave absorbers

The rational design of hollow-structured composite absorbing materials is emerging as a promising approach for enhancing microwave performance. The present study successfully synthesized a series of ZIF-67/MoS2 composites with adjustable size range using a two-step method and achieved the formation of magnetically responsive Co/C/MoS2 hybrids through high temperature pyrolysis. The findings demonstrated that ZIF-67/MoS2 (1:12) exhibited a wide effective attenuation bandwidth (EAB) (5.60 GHz from 12.40 GHz to 18.0 GHz) with a thickness of 2.4 mm, and minimum reflection loss (−43.46 dB) at 2.1 mm. However, Co/C/MoS2 hybrid possessed the better EAB (5.95 GHz from 11.61 GHz to 17.56 GHz) at 1.2 mm and minimum reflection loss (−51.83 dB) at a thickness of 1.0 mm. The ingeniously synthesized ZIF-67/MoS2 and Co/C/MoS2 composites, hence, unravel themselves as a promising and exceedingly efficient contender for lightweight microwave absorption.

Groundwater Environment and Health Risk Assessment in an In Situ Oil Shale Mining Area

To clarify the risk posed to groundwater in oil shale in situ mining areas, we examine five leached pollutants: Fe, Mn, Cr, sulfate, and ammonia nitrogen. Potential groundwater contents of these five pollutants were evaluated using an improved Nemero comprehensive index method and a health risk assessment method. The results show that, compared with the Class III groundwater quality standard (GB/T 14848-2017) used in the People’s Republic of China, average values of Fe, Mn, and sulfate in leaching solution from Fuyu oil shale exceed the standard, while Cr and ammonia nitrogen do not exceed the standard, and the leaching solution is within Class V groundwater quality. The average values of Fe and Mn in the leaching solution from Fushun oil shale exceed the Class III standard, while Cr, sulfate, and ammonia nitrogen values from this oil shale do not exceed the standard, and the leaching solution is Class IV in terms of groundwater quality. The weighting value used in the Nemero assessment method for the heavy metal Cr is the largest as its potential to cause harm to groundwater quality is the largest. The weight value for sulfate is the smallest as the harm degree is the smallest. The chemical carcinogen Cr has the greatest potential impact on human health. The health risk caused by the chemical non-carcinogen Mn is greater than that caused by Fe and ammonia nitrogen. When high pyrolysis temperatures are used, Mn will be released into groundwater in large quantities. Therefore, supervision and control should be strengthened. The results presented here can provide a reference for the comprehensive evaluation of groundwater risks caused by in situ oil shale mining.

Application of Artificial Neural Network (ANN) as a predictive tool for the removal of pharmaceutical from wastewater streams using biochar: a multifunctional technology for environment sustainability

This study investigates biochar as an attractive option for removing pharmaceuticals from wastewater streams utilizing data from various literature sources and also explores the sensitivity of the characteristics and implementation of biochar. ANN 1 was designed to determine the optimal biochar characteristics (Surface Area, Pore Volume) to achieve the maximum percentage removal of pharmaceuticals in wastewater streams. ANN 2 was developed to identify the optimal biomass feedstock composition, pyrolysis conditions (temperature and time), and chemical activation (acid or base) to produce the optimal biochar from ANN 1. ANN 3 was developed to investigate the effectiveness of the biochar produced in ANN 1 and 2 in removing dye from water. Biomass feedstock with a high lignin content and high volatile matter at a high pyrolysis temperature, whether using an acid or base, achieves a high mesopore volume and high surface area. The biochar with the highest surface area and mesopore volume achieved the highest removal percentage. Regardless of hydrophobicity conditions, at low dosages (0.2), a high surface area and pore volume are required for a high percent removal. And with a higher dosage, a lower surface area and pore volume is necessary to achieve a high percent removal.

An experimental and chemical kinetic simulation study of the high-temperature pyrolysis of linear C1–C5 alcohols

The high-temperature pyrolysis characteristics of C1–C5 linear alcohols, including methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol, systematically studied experimentally and the results interpreted using a detailed kinetic model. Specifically, a single-pulse shock tube coupled to a gas chromatography-mass spectrometry (GC-MS) system and a gas chromatograph (GC) is used to conduct a comprehensive experimental study on the high-temperature pyrolysis of the five alcohols, at pressures of 5 and 10 bar, in the temperature range 1000–1800 K at 1% fuel diluted by argon. Qualitative and quantitative analyses are conducted on the reactant, intermediate, and product species involved to determine species distributions as a function of temperature. A detailed chemical kinetic mechanism, NUIGMech1.3, is used to simulate the experimental data under the working conditions. The simulation results are compared with the experimental results, and it is shown that the overall trends between experiments and model predictions are relatively ideal in the comparison of all product and reactant concentrations, even though there is still a phenomenon of inaccurate prediction. Reaction pathway analysis is then conducted on the five alcohols. The present work not only provides additional experimental data for alcohols, but also provides insights into the high-temperature pyrolysis characteristics of the five fuels, which will be valuable for further development and optimization of detailed kinetic mechanisms of these alcohols and promote their practical application.

High-capacity vanadium nitride anode materials synthesized by melamine-assisted pyrolysis

Structurally controllable clustered shuttle metal-organic frameworks (V-MOF) are selected as precursors, and melamine (C3H6N6) derived carbon is encapsulated on the surface of the V-MOFs by using high-temperature pyrolysis, resulting in the formation of N, C-codoped VN electrode materials (VNNC).

LiCl in situ decorated metal-organic framework (MOF)-derived porous carbon for efficient solar-driven atmospheric water harvesting.

Solar-powered sorption-based atmospheric water harvesting (AWH) technology is a promising solution to the freshwater scarcity in arid regions. Existing adsorbent materials still face challenges in aspects such as cycling stability and adsorption kinetics and require further development. Herein, we presented a strategy for the in situ fabrication of high-performance adsorbents, lithium chloride (LiCl)-decorated metal-organic framework (MOF)-derived porous carbon sorbents (PCl), via high-temperature pyrolysis and hydrogen chloride (HCl) vapor treatment. The sorbents display high adsorption capacity across a wide range of humidity water adsorption capacities in a wide humidity range with the maximum adsorption capacity of 7.87 g g-1, and rapid response to the solar-driven process and excellent cyclic stability. The LiCl nanocrystals in PCl can be utilized efficiently and decorated within the porous framework stably, and demonstrate water adsorption at 20%, 40%, 60% and 80% RH, of 1.34, 1.69, 2.56 and 4.23 gH2O·gLiCl-1, respectively, and significantly higher water uptake and release rates than bulk LiCl. This may provide new guides for designing efficient solar-driven AWH.

О применимости зарубежного опыта обращения с твёрдыми коммунальными отходами в Российской Федерации

The features of the world's best practices of SUW handling with the prevailing role of recycling, high-temperature pyrolysis, as well as mixed options are considered. Based on comparative and factor analysis, the SUW management model developed in Germany was chosen as optimal for implementation under Russian conditions. Its potential corresponds to achievement of the stated national goals by 2030, as well as the gradual transition of Rus-sian industry of waste handling to a circular economy.

Understanding pore size relation in cellulose-derived, nitrogen-doped, hydrothermal carbons for improved supercapacitor performance

Eco-friendly supercapacitor electrodes were synthesised using HTC and pyrolysis, yielding capacitance values &gt; 275 F g−1 and power densities ≈ 3000 W kg−1 that were linked to near ideal pore size matching to the electrolyte sulphate ion diameter.

Fabrication of bimetallic MOF-74 derived materials for high-efficiency adsorption of iodine.

Owing to their high porosity, open metal sites, and huge surface area, metal-organic framework (MOF) materials are commonly employed in iodine adsorption processes. Bimetallic MOFs have drawn a lot of attention since mono-metal MOFs have been unable to keep up with the demand. Bimetallic MOF materials still have drawbacks, including limited adsorption capacity, extended adsorption time, poor stability, and poor selectivity, despite their positive performance in radioactive iodine capture. It has been therefore difficult to develop adsorbents with quick iodine adsorption rates and high iodine adsorption efficiency. This study investigated the adsorption properties of a series of bimetallic MOF-74 materials (Mn-Co-MOF-74, Mn-Zn-MOF-74, and Mn-Ni-MOF-74) for radioactive iodine, as well as their design and synthesis utilizing the reflux approach. It was discovered that the adsorption performance of Mn-Ni-MOF-74 for radioiodine was superior to that of the other two bimetallic MOF-74 materials. Using the bimetallic Mn-Ni-MOF-74 as a precursor, a variety of bimetallic MOF-74 derived carbon compounds (Mn-Ni-CX) were prepared by high-temperature pyrolysis. Simultaneously, the structure of the material and the iodine adsorption characteristics have been thoroughly studied.

Regulating the frontier orbital of iron phthalocyanine with nitrogen doped carbon nanosheets for improving oxygen reduction activity.

Iron phthalocyanine (FePc) has attracted widespread attention for its tunable electronic structure. However, the Fe-N sites suffer from undesirable oxygen reduction activity due to the symmetric geometries. A suitable substrate was thus needed to induce electron redistribution around Fe-N to improve the activity. Herein, ultrathin nitrogen-doped carbon nanosheets (N-CNSs) were prepared by a simple high temperature pyrolysis. Then iron phthalocyanine was loaded on the ultrathin nitrogen-doped carbon nanosheets (FePc@N-CNSs) by a low-cost and simple solution method. This composite catalyst shows an excellent ORR activity with a half potential of 0.88 V, an onset potential of 0.99 V and durability superior to commercial Pt/C. When used as an air cathode catalyst for rechargeable zinc-air batteries, FePc@N-CNS modified batteries outperform Pt/C + RuO2 modified batteries with higher power density and superior constant current charge-discharge cycling stability of 37 hours. The regulated electronic structure of FePc by the N-CNS substrate was revealed further by DFT calculations, which explained the enhanced adsorption of the active center to the intermediates and the increased ORR performance.

Effects of pore structures on a phenolic resin-derived self-supported electrode for highly efficient electroreduction of CO2 to syngas

The preparation of a porous self-supported carbon electrode by pressing and high temperature pyrolysis for the efficient electroreduction of CO2 to syngas.

Application of Substrate Materials Derived from Plant Roots, Stems, Leaves, and Microbes for Remediation of Soil Heavy Metal Pollution

This study focuses on the remediation of chromium (Cr), a heavy metal, in soil using substrate materials synthesized from plant roots, stems, leaves, and microbes. Corn was chosen as the source material for biochar production through high-temperature pyrolysis of corn roots, stems, and leaves. The biochar was then modified with an iron solution, and microbial adsorption was employed to remediate heavy metal Cr in the soil. The study involved physical and infrared analyses of the substrate materials and experiments to determine the adsorption contribution of different pH conditions, sites, and substrate materials to metal Cr. The effectiveness of plant roots, stems, leaves, and microbial combinations in remediating soil heavy metal pollution was verified. The experimental results demonstrate a decrease in the Zeta potential values of both materials as the pH increases. Moreover, as pH gradually increases, the form of Cr ions changes, and the reproductive ability of microbes weakens. The substrate materials exhibit a notable increase in negative charge, leading to enhanced repulsion towards Cr, which impacts their adsorption performance. At neutral pH, the adsorption capacity of the substrate materials for Cr is enhanced. The contribution rate of the composite substrate materials in the adsorption process is 6.78%, while that of microbial organisms is 56.45%, significantly higher than that of Fe-CBC. The main reason is that microbial adsorption activity for Cr is enhanced under higher pH conditions, with the contribution rate of microbial organisms continuing to increase significantly at a pH of 9.

Chemodynamic PtMn Nanocubes for Effective Photothermal ROS Storm a Key Anti-Tumor Therapy in-vivo.

Chemodynamic therapy (CDT) is a new treatment approach that is triggered by endogenous stimuli in specific intracellular conditions for generating hydroxyl radicals. However, the efficiency of CDT is severely limited by Fenton reaction agents and harsh reaction conditions. Bimetallic PtMn nanocubes were rationally designed and simply synthesized through a one-step high-temperature pyrolysis process by controlling both the nucleation process and the subsequent crystal growth stage. The polyethylene glycol was modified to enhance biocompatibility. Benefiting from the alloying of Pt nanocubes with Mn doping, the structure of the electron cloud has changed, resulting in different degrees of the shift in electron binding energy, resulting in the increasing of Fenton reaction activity. The PtMn nanocubes could catalyze endogenous hydrogen peroxide to toxic hydroxyl radicals in mild acid. Meanwhile, the intrinsic glutathione (GSH) depletion activity of PtMn nanocubes consumed GSH with the assistance of Mn3+/Mn2+. Upon 808 nm laser irradiation, mild temperature due to the surface plasmon resonance effect of Pt metal can also enhance the Fenton reaction. PtMn nanocubes can not only destroy the antioxidant system via efficient reactive oxygen species generation and continuous GSH consumption but also propose the photothermal effect of noble metal for enhanced Fenton reaction activity.

Waste Rambutan-Derived Porous Carbon Materials Applied to Supercapacitors

The supercapacitor, as a novel energy storage device, possesses the advantages of rapid charging and discharging, extended cycle life, high power density, low energy density, excellent voltage resistance, large capacity, and more. Biomass serves as an ideal electrode material for supercapacitors due to its high carbon content, cost-effectiveness, and environmental friendliness. In this study, waste rambutan peel is utilized as the raw material and subjected to KOH activation following high-temperature pyrolysis to fabricate porous carbon materials with well-ordered pore size distribution. The rambutan peel electrode material exhibits a mass-specific capacitance of 285 F g-1 (at 1 A g-1 current density) and retains 105% after 5000 cycles of charge and discharge. This provides a direction for the reuse of biomass materials.

Synthesis and Application of Bimetal Decorated Plant-Based Carbon Nanomaterial for Hydrogen Storage

Abstract: In this study, carbon nanomaterials (CNMs) were synthesized from waste cotton fibers and examined their hydrogen adsorption capacity. The CNMs were created by subjecting waste cotton fibers to high-temperature pyrolysis at 800°C, followed by activation with alkali solution. Nano-sized metallic particles of Nickel and Aluminium were decorated on the activated carbon fibers. Analysis through SEM, EDAX, Raman spectroscopy, X-ray diffraction and BET surface area confirmed the porous nature and presence of metal particles in the CNMs. These materials exhibited a notably larger specific surface area (SSA) compared to untreated carbon fibers, enhancing their hydrogen storage capabilities as it showed 8.08 wt% of hydrogen adsorption using a Sievert's apparatus. This work, shows the promising potential of these CNMs for hydrogen adsorption in various industrial applications.

Quantitative characterization and analysis of pore-fractures in tar-rich coal under high-temperature pyrolysis based on micro-CT imaging

This study investigates pore distribution and permeability behavior of tar-rich coal following high-temperature pyrolysis at 500°C using X-ray computed tomography (CT) scanning. Coal samples post-pyrolysis were CT scanned, generating 1755 cross-sectional slices for three-dimensional reconstruction. An axial algorithm extracted pore distribution features, and geometric parameters were computed. An Equivalent Pore Network Model analyzed permeability characteristics. The results show that Post-pyrolysis pore distribution in tar-rich coal exhibited nonuniformity with a significant range in pore size distribution. Pores displayed concentrated spatial patterns. Total porosity was 14.24%, with 12.34% being connected. Most pores in Representative Elementary Volume (REV) regions fell within 10–50 μm in width and 20–60 μm in length, constituting over 40% of the total. Pore surface area peaked between 200–100 μm2, also comprising over 40% of the total. The Pore Network Model showed distinct characteristics in two REV regions: REV-1 demonstrated an early stage of development with poor connectivity, while REV-2 displayed a well-developed network with a bimodal coordination number histogram. The study highlights nonuniform post-pyrolysis pore distribution and significant pore size variations in tar-rich coal. This study is crucial for understanding permeability behavior in tar-rich coal after high-temperature pyrolysis.

Unveiling the Potential of Corn Cob Biochar: Analysis of Microstructure and Composition with Emphasis on Interaction with NO2.

In the context of sustainable solutions, this study examines the pyrolysis process applied to corn cobs, with the aim of producing biochar and assessing its effectiveness in combating air pollution. In particular, it examines the influence of different pyrolysis temperatures on biochar properties. The results reveal a temperature-dependent trend in biochar yield, which peaks at 400 °C, accompanied by changes in elemental composition indicating increased stability and extended shelf life. In addition, high pyrolysis temperatures, above 400 °C, produce biochars with enlarged surfaces and improved pore structures. Notably, the highest pyrolysis temperature explored in this study is 600 °C, which significantly influences the observed properties of biochars. This study also explores the potential of biochar as an NO2 adsorbent, as identified by chemical interactions revealed by X-ray photoelectron spectroscopy (XPS) analysis. This research presents a promising and sustainable approach to tackling air pollution using corn cob biochar, providing insight into optimized production methods and its potential application as an effective NO2 adsorbent to improve air quality.

Eco-synthesis, characterization and application of waste plastics pyrolysis char in arsenic removal from contaminated water: An integrated circular framework with parametric response surface methodology optimization-cum-artificial neural network model

Eco-synthesis of a novel, cost-effective activated adsorbent from waste low-density polyethylene plastic pyrolysis char at 550 °C and its arsenic adsorption potential in simulated aqueous media has been investigated. Characterization reveals good surface chemistry and evolved morphology of activated char adsorbent with carbon structures at high pyrolysis temperature, thereby facilitating high arsenic adsorption uptake. A unique integrated framework of kinetic equilibrium investigation, parametric optimization applying response surface methodology (RSM) with responsive arsenic adsorption efficiency and artificial neural network (ANN) model for response validation has been presented. There is reasonably good fitting of experimental equilibrium figures into the Langmuir isotherm model (R2 = 0.9920). The effects of adsorbent pyrochar dose, arsenic concentration, contact time and pH on the arsenic removal capacity have been depicted via conjugate RSM graphs. The ANN regression curves showed R2 value of 0.99436, validating the model with ANN architecture as 4–8-1. Iron oxide complexation with arsenic on adsorbent surface is reported to play a dominant role in the proposed adsorption mechanism. The proposed hybridized model can be applied to examine the adsorptive removal of various contaminants in water. Techno-economic analysis of scaled-up community arsenic filter showed high removal efficiency (> 90%) of arsenic by activated plastic pyro-char adsorbent from contaminated water at an affordable cost of 0.67 $/m3 of treated water. The activated plastic waste pyro-char with an adsorption capacity of 7.21 mg/g is, therefore, environmentally sustainable in plastic waste management in the post-pandemic era for a ‘waste to wealth’ circular economy with perspective arsenic removal from contaminated water.