Pyrolysis Temperature Research Articles

Hollow hydrangea-like Mo2C/MoO2/C composites with tunable phase compositions as highly efficient microwave absorbers

With the advancement of modern electronic communication technology, the development of efficient absorbing materials has attracted great interest. Here, hollow hydrangea-like Mo2C/MoO2/C composites are synthesized by soft template method. By adjusting the pyrolysis temperature, Mo2C/MoO2/C composites with different Mo2C and MoO2 contents and degrees of graphitization can be selectively synthesized. The Mo2C/MoO2/C-800 composite with the 30 wt% filler content exhibits a minimum reflection loss of −62.9 dB at 1.6 mm and achieves a maximum absorption bandwidth of 6.2 GHz at 1.9 mm. The interaction between the dielectric properties of each component and the unique 3D hydrangea-like structure promotes microwave absorption and dissipation. Besides, CST simulation further demonstrates the effectiveness of electromagnetic wave dissipation in practical applications. The excellent properties of the hydrangea-like Mo2C/MoO2/C composites indicate their promising applications in electromagnetic wave absorbers.

Metal-modified biochars prepared from blue algae and their ability of adsorbing phosphates from water and utilization as soil amendment

The problem of blue algae accumulation can be alleviated by utilizing blue algae as biomass for resource utilization, which can remove excess phosphates from water to alleviate eutrophication. Herein, Magnesium (Mg) and/or lanthanum (La) were used to modify biochar via high-temperature slow pyrolysis with blue algae as the raw biomass. These modified biochars exhibited abundant carbon (18.0 %-50.3 %), oxygen content (17.4 %-49.1 %), along with a high specific surface area (82.26–233.80 m2/g). The surface of metal-modified biochar was enriched with hydroxyl and carboxyl groups and metal elements were efficiently incorporated into biochars. Adsorption kinetic and isotherm experiments were conducted under the optimal pyrolysis temperature of 600 °C, pH of 6.0, and adsorbent dosage of 2.0 g/L. The adsorption kinetics studies by metal-modified biochars for phosphate fitted well pseudo-second-order model Redlich-Peterson isotherm model. Biochar modified by Mg and La exhibited the highest removal efficiency (97.8 %) for phosphate at adsorption equilibrium. The adsorption mechanism involved the electrostatic interaction between hydroxylated metal oxides and negatively charged phosphate ions and the precipitation of phosphate ions through chemical reactions with metal oxides in the solution. After phosphate adsorption, the pristine and metal-modified biochars derived from blue algae were applied as the soil amendment. Biochar adsorbed phosphate apparently improved the germination rate of seeds facilitated the height, width, weight, and chlorophyll content of vegetable seedlings, and induced oxidative stress, which proved that the biochar recovered after adsorption was a high-quality soil amendment. This study provides a new approach for the treatment of phosphate wastewater and the algae application.

Porous biochar production from microwave pyrolysis of sugarcane bagasse biomass with KOH addition

ABSTRACT Biomass-based porous carbons have diverse structures and typically exhibit good multifunctionality. Therefore, compared to direct combustion, using pyrolysis to convert agricultural waste into biochar is an environmentally friendly and effective treatment method. Preparing biomass-derived porous carbon materials (PCMs) through microwave is challenging, as biomass rarely absorbs microwave energy and necessitates the inclusion of additional microwave absorbers. In this study, a silicon carbide crucible was designed to simplify the microwave pyrolysis process, and sugarcane bagasse-based porous carbon (GZKM) was prepared using a microwave pyrolysis coupled with KOH activation method without adding additional microwave absorbers. A detailed study was conducted on the yield, surface morphology, and pore structure of biochar obtained from different temperatures (700, 750, 800, 850, and 900 °C) and different mass ratios of sugarcane bagasse to KOH (0, 4:1, 2:1, 1:1, and 1:2). The results indicated that as the pyrolysis temperature and KOH addition increased, the yield of biochar gradually decreased from a highest value of 31.41 wt% to a lowest value of 11.8 wt%. The specific surface area (SBET) of GZKM initially increased and then decreased with the increase in pyrolysis temperature and KOH mass, reaching a maximum value of 889.41 m2/g. The results of this study can provide guidance for the reuse of sugarcane bagasse and the preparation of porous biochar, and can also be applied in fields such as electrocatalysts, batteries, biomedical materials, and wastewater treatment.

Self-doped Na-carbon materials derived from a lyocell fiber for a high-performance trimethylamine gas sensor at room temperature

In this study, biomass-derived carbon material obtained from Lyocell fibers was first utilized as a gas sensor. The impacts of varying pyrolytic carbonization temperatures and pregrinding treatments on the structure, surface morphology, elemental composition, and gas sensitivity of the samples were thoroughly examined. The CL-500 sensor can realize rapid detection of trimethylamine with a high response (12.79k%, 500 ppm) and high selectivity at room temperature; the response/recovery times are 10 s and 2 s, respectively, and the theoretical detection limit is 3.96 ppm. Moreover, after four months, the response of the CL-500 sensor to trimethylamine fluctuated by less than 9.7 % compared with that of the fresh sensor, indicating good stability. It also shows good recovery after seven consecutive response-recovery cycles. Additionally, the CL-500 sensor has promising applications in real-life fish freshness monitoring. Theoretical calculations indicate that the introduction of trace amounts of Na enhances the sensing performance of this sensor for target gases. This study serves as a guide for developing cost-effective, high-performance gas sensors, promoting the efficient and high-value utilization of biomass waste.

Experimental Study on Optimizing Hydrogen Production from Sludge by Microwave Catalytic Pyrolysis Using Response Surface Methodology.

Catalytic pyrolysis technology is a harmless and useful solid waste treatment method. Studying the catalytic pyrolysis of sludge for hydrogen production is of practical significance. Therefore, this paper prepared a bifunctional catalyst with both microwave absorption and catalytic properties from electroplating sludge through carbonization and acid modification processes and then was characterized by XRD, BET, SEM, XPS, and FTIR. An experimental study employed a conventional-then-microwave pyrolysis method to investigate the catalytic pyrolysis process of municipal sludge. Combining central composite design (CCD) and response surface methodology (RSM) with three factors and five levels, this paper investigated the interactive effects of the conventional pyrolysis temperature, microwave irradiation time, and catalyst addition ratio on the unit hydrogen production (UHP) of sludge. A predictive model based on a second-order polynomial regression equation was developed. The results revealed that the catalyst possesses a specific surface area and pore structure and that the second-order polynomial model fits well. The conventional pyrolysis temperature, microwave irradiation time, catalyst addition ratio, and interaction between the latter two significantly affected the UHP of sludge. The optimal operation conditions of conventional pyrolysis temperature, microwave irradiation time, and catalyst addition ratio were 462.7 °C, 8.8 min, and 12.4%, respectively. Under these optimal conditions, the UHP was 13.22 mmol/g, with a relative error of only 1.12% compared to the predicted model value of 13.37 mmol/g.

Exploring the Relationship Between Biochar Pore Structure and Microbial Community Composition in Promoting Tobacco Growth.

The potential benefits of biochar, a carbon-rich substance derived from biomass, for enhancing agricultural yield and soil health have drawn increasing interest. Nevertheless, owing to the lack of specialized studies, the role of its poly-spatial structure in the success of fostering plant growth remains unclear. This study aimed to assess the effects of various biochar pore shapes on tobacco growth and the underlying microbiological processes. Three pyrolysis temperatures (250 °C, 400 °C, and 550 °C) were used to produce biochar from tobacco stems, resulting in different pore structures (T3 > T2 > T1). We then used BET-specific surface area (BET), t.Plot micropore specific surface area (t.Plot), mesopore specific surface area (MSSA), specific pore volume (SPV), average pore size (AP), and mesopore pore volume (MPV) measurements to evaluate the effects of these biochars on tobacco growth and biomass accumulation, and microbial analyses were performed to investigate the underlying mechanisms. When applied to plants, biochar increased their growth compared to untreated controls. The most notable improvement in tobacco growth was observed in the biochar produced at 400 °C (T3), which possessed the largest and most advantageous pore structure among all treatments. Further studies demonstrated that biochars with greater specific surface areas (BET, t.Plot, and MSSA) positively altered the abundance of key microbial taxa (e.g., Stenotrophobacter, Ensifer, Claroideoglomus) and community composition, thereby encouraging plant development and biomass accumulation. Conversely, greater pore volumes (SPV, AP, and MPV) inhibited microbial activity and significantly affected growth and biomass accumulation. Structural equation modeling further demonstrated that the pore structure of biochar greatly affected plant growth by changing the relative abundance and community composition of soil microbes. Maximizing the benefits of biochar in stimulating plant growth and improving soil microbial communities depends on optimizing the material's pore structure, particularly by increasing the specific surface area. These findings will help expand the use of biochar in sustainable agriculture.

Comprehensive evaluation of the physicochemical properties and pyrolysis mechanism of products from the slow pyrolysis of waste coffee shells

Slow pyrolysis is an efficient method for converting agricultural and forestry wastes into valuable resources, thereby addressing energy shortage and environmental pollution. In this study, a slow-pyrolysis experiment of coffee shells (CS) at 450–850 °C was conducted in a tube furnace. The resulting pyrolysis products were comprehensively characterized via FTIR, Raman spectroscopy, nitrogen adsorption analysis via BET theory, SEM, XPS, and PY-GC-MS. Moreover, the pyrolysis reaction mechanism and N transformation pathway of CS were proposed. The results showed that with the increase in pyrolysis temperature, the yield of biochar gradually decreased, and the yield of biogas gradually increased. At 850 °C, the yields of biochar, bio-oil and biogas of CS were 27.13, 35.16 and 37.71 %, respectively (on a dry, ash-free basis). The bio-oil yield was highest at 550 °C, reaching 35.7 %. Notably, biochar exhibited favorable characteristics such as high specific surface area and porosity, demonstrating its potential as both a biomass fuel and an adsorption material. Acetone (78.30 %) and caffeine (8.29 %) was the predominant substance in bio-oil. Biogas was predominantly composed of CO2, CO, CH4 and H2. The pyrolysis process of CS mainly involved the degradation of macromolecules into small molecules, the repyrolysis of small molecules, dehydrogenation, deoxygenation, alkylation, isomerization, and self-condensation. These results provide a theoretical basis for the recycling of waste biomass CS, which has environmental protection significance and economic value.

Efficient Adsorption and Degradation of Tetracycline Hydrochloride Using Metal-Organic Framework-Derived Cobalt-Based Catalysts and Mechanism Insight.

High-performance Co-based catalysts were derived by pyrolysis using synthesized MOFs as self-sacrificial templates. Various catalytic systems were constructed by peroxymonosulfate (PMS) to degrade tetracycline hydrochloride (TC). Adsorption-degradation efficiencies, cycle performance, dynamics, and the adsorption catalytic mechanism of various catalytic systems for TC were studied. The effects of different synthetic solvents, pyrolysis temperatures, and single/bimetallic element compositions on degradation efficiency were innovatively compared. The optimal catalyst and PMS dosage for the experiment were determined to be 10 mg and 0.1 mL, respectively. The results indicated that all catalytic systems could efficiently degrade TC and have a high acid-base resistance. The catalyst activity was significantly influenced by the pyrolysis temperature. The optimum pyrolysis temperatures for Zn@Co-N-C-T, CH3OH@Co-N-C-T, and H2O@Co-N-C-T were 1000, 900 and 900 °C, respectively. More abundant pore structures and active sites were generated in Zn@Co-N-C-1000, exhibiting an excellent TC degradation efficiency and adsorption capacity, achieving 94.73% and 167.564 mg/g, respectively. Meanwhile, the total organic carbon (TOC) of TC (50 mL, 50 mg/L) achieved a removal rate (TOC/TOC0) of 50.28%. Zn@Co-N-C-1000/PMS maintained over 83.27% TC degradation after five cycles. The adsorption mechanism of the catalyst for TC was investigated through the analysis of adsorption kinetics and isotherm models. The quenching test and EPR results indicated that TC was primarily degraded through the nonradical pathway. The efficient degradation of TC is attributed to the rapid electron transfer processes occurring at the two-phase interface and the redox cycling of Co0/Co2+/Co3+. Finally, LC-MS was used to analyze the intermediate products of TC degradation in the Zn@Co-N-C-1000/PMS system, and two degradation pathways were proposed.

Key biochar properties linked to denitrification products in a calcareous soil

Meta-analyses show an overall decrease in soil N2O emissions after biochar (BC) amendment. Nonetheless, N2O mitigation with BC cannot be extrapolated to every BC-soil combination, inasmuch as an increase in soil N2O release has been occasionally reported. We hypothesized that BC characteristics are key, and performed two microcosm experiments to advance in the understanding of the properties associated. We first investigated how 22 well-characterized BCs affect N2O emissions in a calcareous soil under denitrification conditions. Whereas most BCs decreased N2O emissions, some substantially increased N2O emissions. In a second experiment, we selected and further characterized eight of the 22 previous BCs. We applied the 15N-gas-flux method to study how these BCs affect denitrification products (N2O and N2) in the same soil. Results indicate that the interaction between BC and the denitrification process depends on the temperature of pyrolysis. Whereas BCs produced at 400 °C tended to increase total denitrification (N2O+N2) by an average of 28%, BCs produced at 600 °C significantly reduced total denitrification by 53%. Nevertheless, this decline in overall denitrification did not result in a decrease of N2O emissions, as there was a strong shift in the N2O/(N2+N2O) ratio favoring N2O. A redundancy analysis revealed a direct correlation between carboxylic groups on BCs surface and N2O emissions. This research enhances our understanding of the interaction of BC with denitrification, particularly concerning the relevance of the temperature of pyrolysis, and opens up new paths for investigation, crucial for optimizing the application of BCs in different soil environments.Graphical

Characterization, fractionation and untapped potential of phosphate-amended sewage sludge biochar in soil-plant systems

Sewage sludge, a byproduct of wastewater treatment, poses serious environmental and health risks due to its content of organic contaminants, heavy metals, and pathogenic microorganisms. With the growing global production of municipal wastewater, finding effective methods for managing and disposing of sewage sludge has become increasingly urgent. Traditional methods such as land disposal, dumping, and incineration have limitations and environmental drawbacks. However, recent advancements have shown promise in the valorization of sewage sludge, particularly through pyrolysis, which converts it into biochar for use in soil amendment and pollutant mitigation. This study aims to characterize and fractionate phosphate-amended sewage sludge biochar produced at 300 °C, 400 °C, and 500 °C, and to evaluate its potential use in soil-plant systems. It examines nutrient bioavailability in soil after the addition of this biochar and its effects on plant growth. The pyrolysis process resulted in biochar with high alkalinity (7.2–11.1), ash content ranging from 56.9% to 87.3%, and significant phosphorus retention, with phosphorus concentrations increasing with pyrolysis temperature (5.35%–9.38%). Phosphorus fractionation showed a shift toward more stable fractions particularly at 500 °C. Soil incubation experiments indicated increased phosphorus availability with HCl-extractable P showing a high extraction efficiency of up to 94.95%. In plant growth experiments, the amended biochar significantly enhanced growth, with corn showing an increase of up to 28.8% and wheat showing an increase of up to 86% compared to the control in the first four weeks after emergence. These findings indicate that phosphate-amended sewage sludge biochar enhances nutrient availability and supports plant growth, providing a sustainable solution for sewage sludge management, contributing to soil improvement and carbon sequestration, thereby addressing global environmental challenges.

Ni‐MOF‐74 Derived Carbon‐Based Ni Catalysts for Efficient Catalytic Ammonia Synthesis via Pulsed DBD Plasma

ABSTRACTDesigning efficient noble metal‐free catalysts for plasma‐catalytic ammonia synthesis is significant and challenging. Carbon‐based metal catalysts were prepared at different pyrolysis temperatures using the Ni‐MOF‐74 precursor. The effects of Ni‐MOF‐74 and its derived carbon‐based metal catalysts on pulsed dielectric barrier discharge (DBD) plasma ammonia synthesis were investigated. The results showed that Ni‐MOF‐74‐300 with both the MOF structure and nickel metal particles exhibited the best catalytic performance for ammonia synthesis. The ammonia synthesis rate reached 41.38 mmol g−1 h−1, whereas the nitrogen conversion rate was as high as 1.54% with an energy yield of 3.04 g kWh−1. Compared to the situation of plasma only, the ammonia synthesis rate, nitrogen conversion rate, and energy yield were increased by 28.46 times, 5.7 times, and 5.5 times, respectively.

Optimization of wood vinegar from cacao pod shells by response surface methodology

The purpose of this study is to find the optimal conditions for producing wood vinegar from cacao pod shells using Response Surface Methodology (RSM). Box Behnken Design (BBD) was used to optimize the variables of pyrolysis times, temperature, and particle size. Wood vinegar was prepared by slow pyrolysis technology. The RSM with three design variables including pyrolysis duration at 50, 75, and 100 minutes; pyrolysis temperatures at 300°C, 340°C, and 380°C; and particle size of 3, 5 and 7 cm with 15 runs were applied. Chemical characterization of wood vinegar was performed by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The results showed that phenolic, furan, and ketone compounds were the main component in the cacao pod shells vinegar. The optimum production of wood vinegar from cacao pod shells based on RSM results was identified at a pyrolysis time of 100 minutes, a temperature of 353°C, and a particle size of 3 cm.

Effects of co-pyrolysis interaction performance of cellulose and lignin on the gas products and hydrogen generation path

In this study, cellulose and lignin were subjected to co-pyrolysis for the production of syngas. For the pyrolysis experiments, three influencing factors were selected using a response surface method: pyrolysis temperature (400–800 °C), residence time (5–30 min), and lignin mass percentage (0–100 wt%). At a pyrolysis temperature of 477.4 °C, a residence time of 30 min, and a lignin mass percentage of 50 wt%, the actual syngas yield was 77.2 % higher than the theoretical value for the co-pyrolysis. In addition, the hydrogen volume fraction was improved by up to 24.87 % because of the interaction between cellulose and lignin during their co-pyrolysis (pyrolysis temperature of 800 °C, residence time of 17.5 min, lignin mass percentage of 80.65 wt%). Finally, the hydrogen formation process was simulated, using reactive force field molecular dynamics. The results showed that hydrogen molecules began to appear at a simulation time of 0.479 ns and then gradually increased in number with progressing simulation time. In addition, the hydrogen generation pathways were obtained by this simulation method. This study provides a data foundation for optimizing syngas and hydrogen production from biomass.

Single-step pyrolysis of Stipa Tenacissima fibers to hard carbon: A potential route for sodium-ion battery anodes

Hard Carbon (HC) has emerged as a viable candidate for the negative electrode material in sodium-ion batteries (SIBs). This study focuses on the development of a novel HC-negative electrode derived from the pyrolysis of Stipa tenacissima fibers (STF). Prior to pyrolysis, STF underwent a hot water wash pre-treatment, and various pyrolysis temperatures (800 °C, 1000 °C, and 1300 °C) were investigated to elucidate their influence on HC properties and performance. Structural analysis revealed significant differences in the HC structure, highlighting a direct correlation between capacity improvement and the size of accessible micropores for sodium insertion. Composite electrodes were assembled and evaluated in non-aqueous sodium half-cells to assess HC's performance. Notably, increasing the pyrolysis temperature resulted in higher reversible capacity (RC). Specifically, HC prepared at 1300 °C exhibited an RC of 270 mAh g−1, initial coulombic efficiency (ICE) of approximately 60 %, and exceptional reversibility with 99 % capacity retention after 90 cycles at a 25 mA g−1 of current density (CD). These results surpassed those obtained with HC prepared at 800 °C and 1000 °C. Moreover, this study explores the biological, biochemical, biophysical, and structural advantages conferred by STF, making it a promising component in SIBs, with the ultimate goal of establishing long-lasting, high-performance battery systems.

Efficient removal of aqueous ciprofloxacin antibiotic by ZnO/CuO-bentonite composites synthesized via carbon-bed pyrolysis of bentonite and metal co-precipitation

Antibiotics are of emerging concern due to their widespread use, lack of adequate treatment, and for their potential to threaten human health and the environment. Here, a facile fabrication approach for synthesizing ZnO/CuO-bentonite composites was investigated via carbon-bed pyrolysis of bentonite followed by ZnO/CuO co-precipitation. Sorbents were synthesized using a range of bentonite pyrolysis temperatures, metal oxide contents, and ZnO:CuO mass ratios. The ZnO/CuO-bentonite composites exhibited diverse functional groups, excellent mesoporosity, and high specific surface area (135.0 m2 g−1, four times that of pyrolyzed bentonite-only control). Ciprofloxacin removal was maximized at a bentonite pyrolysis temperature of 450 °C, a total metal oxide content of 25 %, and a Zn/Cu ratio between 95:5 and 93:7, and this material had an observed experimental CIP adsorption of 451 mg g−1 and a calculated maximum adsorption capacity of 1249.3 mg g−1. This excellent CIP sorption ability was attributed to its abundant surface active sites and multiple sorption mechanisms, including hydrogen-bond interaction, ion exchange, and electrostatic interaction. These results illustrate that ZnO/CuO-bentonite composite sorbents have excellent potential for use in environmental remediation and water treatment applications.

A Carbon Capture and Utilization Process for the Production of Solid Carbon Materials from Atmospheric CO2 - Part 2: Carbon Characterization.

This article is the second part of a study reporting the results of a novel carbon capture and utilization (CCU) process, which converts atmospheric CO2 into solid carbon materials. The CCU process combines direct air capture (DAC) with catalytic methanation, which is then followed by methane pyrolysis in a reactor filled with liquid tin. While Part 1 discussed the performance of the overall process and individual process steps regarding conversions and yields, Part 2 characterizes the solid carbon products obtained under various synthesis conditions. The effects of the pyrolysis temperature and the composition of the gas mixture from the methanation step on the solid carbon product are analyzed. Carbon powder is synthesized from methane with either H2 or CO2 as most important impurity. Carbon samples are characterized using SEM, TEM, Raman spectroscopy, XPS and XRD analysis. Very thin, disordered carbon flakes, soot aggregates and large carbon onions are identified as the main solid products of the process. Their formation mechanisms in the liquid metal-filled pyrolysis reactor are discussed.

Mandarin Peels-Derived Carbon Dots: A Multifaceted Fluorescent Probe for Cu(II) Detection in Tap and Drinking Water Samples.

Carbon dots (CDs) derived from mandarin peel biochar (MBC) at different pyrolysis temperatures (200, 400, 600, and 800 °C) have been synthesized and characterized. This high-value transformation of waste materials into fluorescent nanoprobes for environmental monitoring represents a step forward towards a circular economy. In this itinerary, CDs produced via one-pot hydrothermal synthesis were utilized for the detection of copper (II) ions. The study looked at the spectroscopic features of biochar-derived CDs. The selectivity of CDs obtained from biochar following carbonization at 400 °C (MBC400-CDs towards various heavy metal ions resulted in considerable fluorescence quenching with copper (II) ions, showcasing their potential as selective detectors. Transmission electron microscopic (TEM) analysis validated the MBC-CDs' consistent spherical shape, with a particle size of <3 nm. The Plackett-Burman Design (PBD) was used to study three elements that influence the F0/F ratio, with the best ratio obtained with a pH of 10, for 10 min, and an aqueous reaction medium. Cu (II) was detected over a dynamic range of 4.9-197.5 μM and limit of detection (LOD) of 0.01 μM. Validation testing proved the accuracy and precision for evaluating tap and mountain waters with great selectivity and no interference from coexisting metal ions.

Soft soil stabilization using co-pyrolytic biochars from sewage sludge and Nymphaeale, an invasive plant biomass

This research addresses a significant gap in current literature by proposing an alternative to traditional carbon positive soil stabilizers by utilizing sewage sludge in conjugation with Nymphaeale, an invasive plant biomass derived co-pyrolytic biochars to stabilize the soft soil, with a focus on understanding strength gaining mechanism. Various combinations of sewage sludge and Nymphaeale biomass underwent thermogravimetric analysis in a nitrogen environment, suggesting 450°C as pyrolysis temperature for biochar synthesis. Soft soil, which is considered problematic for construction, was blended with five distinct dosages (0%, 5%, 7.5%, 10%, and 12.5%) of biochars (BC75:25, BC50:50, BC25:75) by weight and unconfined compressive strength values were examined over curing periods of 1, 7, 14, and 28 days. The stress-strain and failure behaviour of soil-biochar mixes varied depending on the type of biochar used. SBC25:75 mixes exhibited ductile behaviour, whereas SBC75:25 mixes showed comparatively brittle failure. Furthermore, unconfined compressive strength values of soil-biochar mixes increased 4–5 times with maximum strength achieved at 10% dosage of BC50:50. Biochar dosages led to a reduction in moisture content and an increase in alkalinity and conductivity of the mixes, facilitating the initiation of pozzolanic reactions. The combined findings from the various analyses suggested that the presence of free oxides of calcium in biochars disrupted the laminated structure of the soil and reacted with silica and other aluminum silicates, resulting in the densification of the structure and the formation of cementing mineral phases in the mixes. Overall, the research-work emphasizes the idea of creating novel environmentally friendly binders for soil stabilization through the utilization of waste materials.

Biochar Production From Plastic‐Contaminated Biomass

ABSTRACTAnaerobic digestion and composting of biowastes are vital pathways to recycle carbon and nutrients for agriculture. However, plastic contamination of soil amendments and fertilizers made from biowastes is a relevant source of (micro‐) plastics in (agricultural) ecosystems. To avoid this contamination, plastic containing biowastes could be pyrolyzed to eliminate the plastic, recycle most of the nutrients, and create carbon sinks when the resulting biochar is applied to soil. Literature suggests plastic elimination mainly by devolatilization at co‐pyrolysis temperatures of &gt; 520°C. However, it is uncertain if the presence of plastic during biomass pyrolysis induces the formation of organic contaminants or has any other adverse effects on biochar properties. Here, we produced biochar from wood residues (WR) obtained from sieving of biowaste derived digestate. The plastic content was artificially enriched to 10%, and this mixture was pyrolyzed at 450°C and 600°C. Beech wood (BW) chips and the purified, that is, (macro‐) plastic‐free WR served as controls. All biochars produced were below limit values of the European Biochar Certificate (EBC) regarding trace element content and organic contaminants. Under study conditions, pyrolysis of biowaste, even when contaminated with plastic, can produce a biochar suitable for agricultural use. However, thermogravimetric and nuclear magnetic resonance spectroscopic analysis of the WR + 10% plastics biochar suggested the presence of plastic residues at pyrolysis temperatures of 450°C. More research is needed to define minimum requirements for the pyrolysis of plastic containing biowaste and to cope with the automated identification and determination of plastic types in biowaste at large scales.

An Overview of Biochar Utilization Strategies for Screen-Printed Electrochemical Sensors

In this review, we address the utilization of biochar, a cost-effective material derived from renewable resources (biomass), for the construction of printable electrochemical devices. Key parameters influencing the final properties of biochar, including pyrolysis temperature, pyrolysis duration, heating rate, and activation treatments, are detailed. The role of biochar in the fabrication of electrochemical (bio)sensors is highlighted with emphasis on advancements in screen-printed electrochemical devices. Furthermore, this review showcases examples of using biochar in the construction of portable and flexible screen-printed electrodes, as well as humidity sensors. Future perspectives and challenges in the field of biochar-based electrochemical sensors and biosensors are also discussed, providing a comprehensive outlook on this promising area of research.