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To evaluate the potential of compost based on municipal solid waste (MSW) and 20% legume pruning under a pyrolysis process, generated products, including solids (biochar), liquids (bio-oil), and gases (non-condensable gases), through experimentation in a pilot plant with a fluidized bed reactor at 450°C and gas chromatography/mass spectrometry have been analysed. In addition, the compost kinetic behaviour by thermogravimetric analysis (TGA), using the Flynn-Wall-Ozawa (FWO) method, has been investigated. Four different reaction zones, associated with lignocellulosic materials (hemicellulose, cellulose, and lignin) with a first step for water evaporation, in TGA curve have been observed. A biochar with low stability and aromaticity, considering high and low O/C and H/C ratios, respectively, has been obtained. The obtained pyrolytic liquids contain a high concentration of phenolic compounds because of a significant presence of lignins and other high molecular weight compounds in the original material. Moreover, the generated non-condensable gases consist mainly of short-chain compounds, such as alcohols, aldehydes, and alkenes produced from hemicellulose, cellulose, and proteins., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

To investigate the effect of pyrolysis temperature on the adsorption behavior of the emerging organic pollutant tris-(1-chloro-2-propyl) phosphate (TCIPP) on biochar, corn stover was used as raw materials to prepare biochars at different pyrolysis temperatures (250, 350, 500, 700 °C) through limited oxygen carbonization. Elemental analysis, Boehm titration, FTIR, XPS, and other analytical methods were used to reveal the effect of pyrolysis temperature on the physicochemical properties of biochar and its mechanism of TCIPP adsorption. The results showed that the pyrolysis temperature had a significant impact on the physicochemical properties of biochar. As the pyrolysis temperature increases, the specific surface area of biochar rises from 3.083 m 2 /g to 435.573 m 2 /g, the pH value increases from 6.60 to 10.66, the mass percentage of C increases from 63.10 to 80.58%, and the mass percentage of O decreases from 26.42 to 9.20%. Additionally, the hydrophobicity and aromaticity of biochar also increase with rising pyrolysis temperature, while its polarity decreases. Boehm titration, FTIR, and XPS analysis showed that the total amount of functional groups on the surface of biochar decreased relatively with increasing temperature. Functional groups such as -OH, C = C/C = O, and C-O-C participated in the adsorption of TCIPP on biochar, and ester groups were produced after adsorption. The adsorption process of TCIPP on biochar fits best with the pseudo-second-order equation, indicating that the adsorption process is mainly chemical adsorption, and the main rate-controlling stage is intraparticle diffusion. The isothermal adsorption results were more in line with the Temkin model, indicating that the adsorption process of TCIPP on biochar was mainly surface adsorption. As the pyrolysis temperature increases, the maximum adsorption capacity of biochar increases from 0.8837 mg/g to 2.2574 mg/g. The adsorption process of TCIPP on biochar mainly included pore filling, hydrogen bonding, P-π interaction, hydrophobic interaction, and electrostatic attraction. Among them, pore filling, P-π interaction, and hydrophobic interaction were significantly enhanced with increasing temperature, while hydrogen bonding was relatively weakened. This study will provide a theoretical basis and technical support for the removal of TCIPP from water using biochar adsorption., (© 2024. The Author(s).)

Biosolids from municipal wastewater treatment contain many contaminants of emerging concern, including microplastics (MPs), per- and polyfluoroalkyl substances (PFAS), pharmaceuticals and chemicals from personal care products (PPCPs). Many of these contaminants have very slow biotic or abiotic degradation rates and have been shown to have human and ecological health impacts. Application of biosolids to agriculture, a common disposal method, can result in extended environmental contamination. An approach for eliminating the contaminants is pyrolysis, which can also generate biochar, enhancing carbon sequestration as a side-benefit. We pyrolyzed biosolid samples from an operating facility at various temperatures from 400 to 700 °C with a 2-hour residence time. We then evaluated contaminant removal, which in many cases was 100 %, with only a few residuals. No trace of PFAS was detectable even at 400 °C. Overall mass removal of PPCPs, including PFAS, was over 99.9 %. MP removal via pyrolysis ranged from 91 to 97 %. The biochar contains significant amounts of Fe and P, which make it a useful fertilizer amendment. The techno-economic analysis indicates that pyrolysis may generate significant cost savings, and revenue from the sale of biochar, sufficient to more than cover the investment and operating costs of the dryer and pyrolysis unit., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The world's phosphorus (P) resources are gradually depleting. Sewage sludge is an important secondary P resource, and sludge-derived biochar for land use is an effective way to achieve P recovery. However, P in biochar synthesized by direct pyrolysis of sludge usually shows comparatively low bioavailability. In this study, biomass ash from different types of straw was used as an additive for co-pyrolysis with sludge. The distribution of different P fractions in the obtained co-pyrolyzed biochar was investigated. The P bioavailability of the co-pyrolyzed biochar was comprehensively evaluated by three methods, including chemical extraction, diffusive gradients in thin films (DGT) technology and pot experiments. The results indicate that the bioavailable P in co-pyrolyzed biochar is significantly positively correlated with the contents of K, Ca, and Mg elements in straw ash, which facilitate the transformation of P in sludge into forms that are more easily utilized by plants, including monetite (CaHPO 4 ), hydroxyapatite (Ca 5 (PO 4 ) 3 OH) and pyrocoproite (K 2 MgP 2 O 7 ). Moreover, pot experiments show that the P contents in ryegrass shoots and roots cultivated in co-pyrolyzed biochar-added soils increased by 11.98-114.97 % and 28.90-69.70 %, respectively, compared to the control soil. The DGT technology could better reflect the uptake of P by plants with a Pearson correlation coefficient as high as 0.94. This study provides references for P resource recovery, and the collaborative reutilization of sewage sludge and straw ash., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, pyrolysis was performed at different times to convert Oedogonium biomass into biochar. The physicochemical properties show that the pyrolysis time significantly impacts structural and morphological changes in biochar samples. The influence of pyrolysis time on the removal of multiple heavy metals was investigated. Owing to the presence of abundant functional groups, inorganic minerals and porous nature, biochar obtained from a 40 min pyrolysis time showed higher removal efficiency of heavy metals compared to biochars pyrolyzed at 20 mins and 60 mins even with higher concentrations of metal ions. The maximum adsorption capacity was observed 9.33, 10.74, 322.58, 13.70 and 9.11 mg/g with the biochar prepared at the pyrolysis time of 40 mins for Co, Ni, Cu, Zn and Cd, respectively. The adsorption isotherm is well fitted with the Langmuir adsorption model for heavy metals adsorption, and the kinetic study is well-defined by a pseudo second-order model., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study aimed to assess the effectiveness of urban derived biochars such as Sugarcane bagasse (SB), Brinjal Stem (BS), and Citrus Peel (CP) produced at two different pyrolysis conditions (450 and 600 °C for 60 min) for soil heavy metal bioremediation potential. An ex-situ study was conducted to remediate single heavy metal-contaminated SoilRite with lead (Pb), copper (Cu), chromium (Cr) and cadmium (Cd), with biochars applied at different rates. Heavy metal status in soilrite was evaluated using various extraction methods (water-soluble, exchangeable, TCLP (Toxicity Characteristic Leaching Procedure), and PBET (Physiologically Based Extraction Tests)) to determine the biochar treatments' efficacy. The findings show that SB biochar at 450-60 are more effective in immobilizing heavy metals in water-soluble (Cd-100% Pb and Cu-70%), exchangeable (Pb:91%, Cd and Cu by 70-80%) and PBET-extracted forms (Cd-91%, Pb-80%, and Cu-75%), whereas biochar derived from BS (84%) and CP (90%) at 600-60 are more effective in immobilizing TCLP-extracted form of Pb and Cu. Urban derived biochars significantly reduced the toxicity of Pb, Cu, and Cd in various extractable forms and can stabilize and convert them into less accessible forms except for Cr. These extraction methods aid in evaluating environmental risks and influencing remediation strategies for soil heavy metal pollution. Urban biochar, as a cost-effective and eco-friendly solution, significantly solves this issue, facilitating sustainable waste management., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

In this study, biochar derived from chestnut shells was synthesized through pyrolysis at varying temperatures from 300 °C to 900 °C. The study unveiled that the pyrolysis temperature is pivotal in defining the physical and chemical attributes of biochar, notably its adsorption capabilities and its role in activating peracetic acid (PAA) for the efficient removal of acetaminophen (APAP) from aquatic environments. Notably, the biochar processed at 900 °C, referred to as CN900, demonstrated an exceptional adsorption efficiency of 55.8 mg g -1 , significantly outperforming its counterparts produced at lower temperatures (CN300, CN500, and CN700). This enhanced performance of CN900 is attributed to its increased surface area, improved micro-porosity, and a greater abundance of oxygen-containing functional groups, which are a consequence of the elevated pyrolysis temperature. These oxygen-rich functional groups, such as carbonyls, play a crucial role in facilitating the decomposition of the O-O bond in PAA, leading to the generation of reactive oxygen species (ROS) through electron transfer mechanisms. This investigation contributes to the development of sustainable and cost-effective materials for water purification, underscoring the potential of chestnut shell-derived biochar as an efficient adsorbent and catalyst for PAA activation, thereby offering a viable solution for environmental cleanup efforts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Pyrolysis has emerged as a promising technology for valorizing digestate resulting from the anaerobic digestion of food waste. However, the high NO X emissions during pyrolysis limit its application. This study proposed a hydrothermal coupled pyrolysis process to control the element transfer in digestate during biochar production. The efficient reduction of NO X emissions and the improvement of biochar adsorbability were realized. The hydrothermal process reduced the nitrogen content in solid digestate by 49.10 %-81.79 %, thus reducing the NO X precursors in syngas and the N-containing substances in bio-oil. Additionally, the specific surface area and the total pore volume of biochar were enhanced from 25 m 2 /g to 60-73 m 2 /g and 0.06 cm 3 /g to 0.12-0.14 cm 3 /g, respectively. More defects, oxygen-containing functional groups, and doped Ca on the biochar resulted in a high phosphate removal efficiency of 94 %. The proposed technology provides an efficient and environmentally friendly way to utilize the digestate., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The United Nations proposed the Sustainable Development Goals with the aim to make human settlements in cities resilient and sustainable. The excessive discharge of urban waste including sludge and garden waste can pollute groundwater and lead to the emission of greenhouse gases (e.g., CH 4 ). The proper recycling of urban waste is essential for responsible consumption and production, reducing environmental pollution and addressing climate change issues. This study aimed to prepare biochar with high adsorption amounts of iodine using urban sludge and peach wood from garden waste. The study was conducted to examine the variations in the mass ratio between urban sludge and peach wood (2/1, 1/1, and 1/2) as well as pyrolysis temperatures (300 °C, 500 °C, and 700 °C) on the carbon yield and adsorption capacities of biochar. Scanning electron microscopy, Brunauer-Emmett-Teller analysis, Fourier transform infrared spectrometry, powder X-ray diffraction, and elemental analysis were used to characterize the biochar produced at different pyrolysis temperatures and mass ratios. The results indicate that the carbon yield of biochar was found to be the highest (>60%) at a pyrolysis temperature of 300 °C across different pyrolysis temperatures. The absorbed amounts of iodine in the aqueous solution ranged from 86 to 223 mg g -1 at a mass ratio of 1:1 between urban sludge and peach wood, which were comparably higher than those observed in other mass ratios. This study advances water treatment by offering a cost-effective method by using biochar derived from the processing of urban sludge and garden waste.

Biochar is a high-carbon-content organic compound that has potential applications in the field of energy storage and conversion. It can be produced from a variety of biomass feedstocks such as plant-based, animal-based, and municipal waste at different pyrolysis conditions. However, it is difficult to produce biochar on a large scale if the relationship between the type of biomass, operating conditions, and biochar properties is not understood well. Hence, the use of machine learning-based data analysis is necessary to find the relationship between biochar production parameters and feedstock properties with biochar energy properties. In this work, a rough set-based machine learning (RSML) approach has been applied to generate decision rules and classify biochar properties. The conditional attributes were biomass properties (volatile matter, fixed carbon, ash content, carbon, hydrogen, nitrogen, and oxygen) and pyrolysis conditions (operating temperature, heating rate residence time), while the decision attributes considered were yield, carbon content, and higher heating values. The rules generated were tested against a set of validation data and evaluated for their scientific coherency. Based on the decision rules generated, biomass with ash content of 11-14 wt%, volatile matter of 60-62 wt% and carbon content of 42-45.3 wt% can generate biochar with promising yield, carbon content and higher heating value via a pyrolysis process at an operating temperature of 425°C-475°C. This work provided the optimal biomass feedstock properties and pyrolysis conditions for biochar production with high mass and energy yield.

Large amount of wastes are burnt or left to decompose on site or at landfills where they cause air pollution and nutrient leaching to groundwater. Waste management strategies that return these food wastes to agricultural soils recover the carbon and nutrients that would otherwise have been lost, enrich soils and improve crop productivity. The incorporation of liming materials can neutralize the protons released, hence reducing soil acidity and its adverse impacts to the soil environment, food security, and human health. Biochar derived from organic residues is becoming a source of carbon input to soil and provides multifunctional values. Biochar can be alkaline in nature, with the level of alkalinity dependent upon the feedstock and processing conditions. This study conducted a characterization of biochar derived from the pyrolysis process of eggplant and Acacia nilotica bark at temperatures of 300 °C and 600 °C. An analysis was conducted on the biochar kinds to determine their pH, phosphorus (P), as well as other elemental composition. The proximate analysis was conducted by the ASTM standard 1762-84, while the surface morphological features were measured using a scanning electron microscope. The biochar derived from Acacia nilotica bark exhibited a greater yield and higher level of fixed carbon while possessing a lower content of ash and volatile components compared to biochar derived from eggplant. The eggplant biochar exhibits a higher liming ability at 600 °C compared to the acacia nilotica bark-derived biochar. The calcium carbonate equivalent, pH, potassium (K), and phosphorus (P) levels in eggplant biochars increased as the pyrolysis temperature increased. The results suggest that biochar derived from eggplant could be a beneficial resource for storing carbon in the soil, as well as for addressing soil acidity and enhancing nutrients availability, particularly potassium and phosphorus in acidic soils., (© 2024. The Author(s).)

The interaction effects between the main components (proteins (P), carbohydrates (C), and lipids (L)) of protein-rich biomass during microwave-assisted pyrolysis were investigated in depth with an exploration of individual pyrolysis and copyrolysis (PC, PL, and CL) of model compounds. The average heating rate of P was higher than those of C and L, and the interactions in all copyrolysis groups reduced the max instant heating rate. The synergistic extent ( S ) of PC and PL for bio-oil yield was 16.78 and 18.24%, respectively, indicating that the interactions promoted the production of bio-oil. Besides, all of the copyrolysis groups exhibited a synergistic effect on biochar production ( S = 19.43-28.24%), while inhibiting the gas generation, with S ranging from -20.17 to -6.09%. Regarding the gaseous products, apart from H 2 , P, C, and L primarily generated CO 2 , CO, and CH 4 , respectively. Regarding bio-oil composition, the interactions occurring within PC, PL, and CL exhibited a significantly synergistic effect ( S = 47.81-412.96%) on the formation of N -heterocyclics/amides, amides/nitriles, and acids/esters, respectively. Finally, the favorable applicability of the proposed interaction effects was verified with microalgae. This study offers valuable insights for understanding the microwave-assisted pyrolysis of protein-rich biomass, laying the groundwork for further research and process optimization.

Despite policies to restrict the mixing of organic waste with other general waste and improve its separation at source, municipal solid waste still contains a high proportion of organic waste. The residual organic waste is generated as a by-product of the mechanical treatment of municipal solid waste (MSW) and is mainly disposed in landfills after composting. Its reuse and recovery status varies across European countries. Most countries restrict the use of biostabilised residual waste (BSRW) to landfill cover, whereas others have regulated it as marketable compost. Crucially, BSRW is set to lose its "recycled" status under the revised European Union waste framework, with probably tighter restrictions and increased costs imposed for the landfilling of organic waste. Our research aimed to investigate pyrolysis as an alternative technology to treat the 10-40 mm fraction of BSRW (representing 50% of BSRW generated). Pyrolysis at 700 °C was carried out and feedstock and pyrolysis products were characterized. Mass and energy balances showed that pyrolysis produced hot vapour/gas whose combustion may render the pyrolysis process energetically sustainable. Biochar comprises 30-50% of BRSW mass after removal of glass, metal and stones. Our results indicate that pyrolysis has the potential to create options for contributing to reduce the landfilling of BSRW; however, the presence of residual impurities may limit biochar applications., (© 2024. The Author(s).)

This study evaluates pyrolysis products obtained from biomasses (silver grass, pine, and acacia) harvested from heavy-metal-contaminated soil. To do so, we utilized two methods: a batch one-stage pyrolysis, and a continuous two-stage pyrolysis. The study results show that the yields and characteristics of bio-oils and biochars varied depending on the pyrolysis process and the type of biomass. The two-stage pyrolysis having two reactors (auger and fluidized bed reactors) appeared to be very suitable for specific chemicals production such as acetic acid, acetol, catechol, and levoglucosan. The biochar obtained from the fluidized-bed reactor of two-stage pyrolysis had high thermal stability, high crystallinity, high inorganic content, and a small number of functional groups. In contrast, the biochar obtained from the one-stage pyrolysis had low thermal stability, low crystallinity, a high carbon content, and a large number of functional groups. The biochar obtained from the two-stage pyrolysis appeared to be suitable as a material for catalyst support and as an adsorbent. The biochar obtained from one-stage pyrolysis appeared to be a suitable as a soil amendment, as an adsorbent, and as a precursor of activated carbon. All biochars showed a negative carbon footprint. In the end, this study, which was conducted using two different processes, was able to obtain the fact that products of pyrolysis biomass contaminated with heavy metals have different characteristics depending on the process characteristics and that their utilization plans are different accordingly. If the optimal utilization method proposed through this study is found, pyrolysis will be able to gain importance as an effective treatment method for biomass contaminated with heavy metals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The use of biochar for soil improvement and emission reduction has been widely recognized for its excellent performance. However, the choice of feedstock and pyrolysis temperature for biochar production significantly affects its surface parameters and interactions with soil substances. In this study, we retrieved 465 peer-reviewed papers on the application of biochar in reducing greenhouse gas emissions and nutrient losses in soil and analyzed the changes in biochar physicochemical parameters from different feedstock and pyrolytic temperatures. Molecular simulation computing technology was also used to explore the impacts of these changes on the interaction between biochar and soil substances. The statistical results from the peer-reviewed papers indicated that biochar derived from wood-based feedstock exhibits superior physical characteristics, such as increased porosity and specific surface area. Conversely, biochar derived from straw-based feedstock was found to contain excellent element content, such as O, N, and H, and biochar derived from straw and produced at low pyrolysis temperatures contains a significant number of functional groups that enhance the charge transfer potential and adsorption stability by increasing surface charge density, charge distribution and bonding orbitals. However, it should be noted that this enhancement may also activate certain recalcitrant C compounds and promote biochar decomposition. Taken together, these results have significant implications for biochar practitioners when selecting suitable feedstock and pyrolysis temperatures based on agricultural needs and increasing their understanding of the interaction mechanism between biochar and soil substances., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Pyrolysis is an effective method for treating of livestock and poultry manure developed in recent years. It can completely decompose pathogens and antibiotics, stabilize heavy metals, and enrich phosphorus (P) in biochar. To elucidate the P migration mechanism under different pig manure pyrolysis temperatures, sequential fractionation, solution 31 P nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction, and K-edge X-ray absorption near-edge structure techniques were used to analyze the P species in pig manure biochar (PMB). The results indicated that most of the organic P in the pig manure was converted to inorganic P during pyrolysis. Moreover, the transformation to different P groups pathways was clarified. The phase transition from amorphous to crystalline calcium phosphate was promoted when the temperature was above 600 °C. The content of P extracted by hydrochloric acid, which was the long-term available P for plant uptake, increased significantly. PMB pyrolyzed at 600 °C can be used as a highly effective substitute for P source. It provides the necessary P species (e.g. water-soluble P.) and metal elements for the growth of water spinach plants, and which are slow-release comparing with the Hogland nutrient solution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The higher heating value of biochar is an important parameter for the utilization of biomass energy. In this work, extreme gradient boosting regression and artificial neural network were used to predict it based on the characteristics of biomass and pyrolysis conditions. Besides, empirical correlations were developed for comparison. Results showed that the extreme gradient boosting regression models showed better performance (R 2  = 0.83-0.94). The shapley additive explanations and partial dependence plot indicated that lignin content and higher heating value of raw material were highly positively correlated with higher heating value of biochar, and found the better conditions such as pyrolysis temperature (>550 °C), lignin content (>40 wt%) for high-higher heating value biochar preparation. What's more, a program that predicted higher heating value of biochar was developed through PySimpleGUI library. It offered a new optimization idea for the directional preparation process of biochar., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The nettle, sage, mint and lemon balm herbs were used for biochars preparation. The physicochemical parameters of obtained materials were related to the lignocellulose composition of the precursors. It has been proved that the content of mineral substance has a significant influence on development of surface area, whereas the amount of hemicellulose affects the content of surface functional groups. It has been also shown that the obtained biochars are characterized by great energy parameters. The higher heating values (HHV) of the carbonaceous materials are comparable to the typical energy sources. The greatest HHV value (20.36 MJ/kg) was characteristic for the biochar obtained by pyrolysis of the lemon balm. In addition, the biochars were used for ionic polymers adsorption from one- and two-components solutions. Despite the adsorbed amounts of macromolecules are not great is has been proved that polyethylenimine and polyacrylic acid have positive influence on their mutual adsorption., (© 2024 Wiley-VCH GmbH.)

Endogenous mineral of plant such as potassium, calcium and iron may play a crucial role in boosting the physicochemical structure and catalytic activity of high temperature pyrolyzed plant-based biochar while it is often neglected owing to its relative less content. Herein, self-template pyrolyzed plant-based biochars were prepared from two different ash-contained agricultural wastes of peanut hull (PH, 3.2% ash) and cotton straw (CS, 0.8% ash), and aimed at investigating the relationship among the endogenous mineral fractions of plant-based biomass, physicochemical active structure and persulfate (PS) catalytic degradation activity for tetracycline (TC). The results of energy/spectral characterization showed that under the self-template effect and pyrolysis catalysis of endogenous minerals, PH biochar (PBC) possessed much more specific surface area, conjugated graphite domain, C=O and pyrrolic-N surface active functional sites than CS biochar (CBC), enhancing TC removal rate of PBC/PS to 88.37%, twice that of CBC/PS (44.16%). Meanwhile, reactive oxygen quenching and electrochemical experiments showed that electrons transfer and non-free radical pathways based on singlet oxygen contributed 92% of TC removal in PBC/PS system. Remarkably, by comparing the differences in structure and TC removal performance of pre-deashing and non-deashing prepared plant-based biochars, a possible mechanism for endogenous mineral components' self-template effect and pyrolysis catalysis role of plant-based biomass was proposed. This study provides a new insight for revealing the intrinsic mechanism of mineral elements enhancing the active surface structures and catalytic properties of plant-based biochars derived from distinct feedstocks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Millets are receiving increasing attention, lately, in view of their preeminent agronomic traits, nutritional significance, and renewed emphasis on highlighting their health benefits through national and international programs. As a consequence, a variety of millets are being cultivated in different parts of the world resulting in significant amount of millet agro-residues. Present study comprehends critical analysis of reported investigations on pyrolysis of different millet agro-residues encompassing (i) physico-chemical characterization (ii) kinetics and thermodynamic parameters (iii) reactors employed and (iv) relationship between the reaction conditions and characteristics of millets-derived biochar and its prospective applications. Based on the analysis of reported investigations, specific research gaps have been figured out. Finally, future directions for leveraging the energy potential of millet agro-residues are also discussed. The analysis elucidated is expected to be useful for the researchers for making further inroads pertaining to sustainable utilization of millet agro-residues in tandem with other commonly employed agro-residues., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

More people globally are now using on-site sanitation technologies than sewered connections. The management of faecal sludge generated by on-site facilities is still challenging and requires an understanding of all sanitation service chain components and their interactions; from source conditions to treatment and resource recovery. This study aimed to improve the current lack of knowledge regarding these interactions, by establishing a quantifiable relationship between human excreta source separation and resource recovery via pyrolysis. The effects of source separation of faeces and urine on biochar quality were investigated for different pyrolysis temperatures (450 °C, 550 °C, 650 °C) and this information was used to assess energy and nutrient recovery. Results quantify the benefits of urine diversion for nitrogen recovery (70% of total N losses during thermal treatment avoided) and show an increase in the liming potential of the produced faecal-based biochars. The quality of produced solid fuels is also improved when source-separated faeces (SSF) are used as a feedstock for pyrolysis, including a 50% increase in char calorific value. On the other hand, biochars from mixed urine and faeces (MUF) are more rich in phosphorus and potassium, and surface morphology investigation indicates higher porosity compared to SSF biochars. The high salinity of MUF biochars should be considered before agricultural applications. For both biochar types (SSF, MUF), the presence of phosphate compounds of high fertiliser value was confirmed by X-ray diffraction analysis, and temperatures around 500 °C are recommended to optimise nutrient and carbon behaviour when pyrolysing human excreta. These findings can be used for the design of circular faecal sludge management systems, linking resource recovery objectives to source conditions, and vice-versa. Ultimately, achieving consistent resource recovery from human excreta can act as an incentive for universal access to safe and sustainable sanitation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The agricultural industry faces a permanent increase in waste generation, which is associated with the fast-growing population. Due to the environmental hazards, there is a paramount demand for generating electricity and value-added products from renewable sources. The selection of the conversion method is crucial to develop an eco-friendly, efficient and economically viable energy application. This manuscript investigates the influencing factors that affect the quality and yield of the biochar, bio-oil and biogas during the microwave pyrolysis process, evaluating the biomass nature and diverse combinations of operating conditions. The by-product yield depends on the intrinsic physicochemical properties of biomass. Feedstock with high lignin content is favourable for biochar production, and the breakdown of cellulose and hemicellulose leads to higher syngas formation. Biomass with high volatile matter concentration promotes the generation of bio-oil and biogas. The pyrolysis system's conditions of input power, microwave heating suspector, vacuum, reaction temperature, and the processing chamber geometry were influence factors for optimising the energy recovery. Increased input power and microwave susceptor addition lead to high heating rates, which were beneficial for biogas production, but the excess pyrolysis temperature induce a reduction of bio-oil yield., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Sediment enrichment with biochar, a high-carbon material produced by the pyrolysis of biomass, is a promising remediation strategy for metal pollution. The metal immobilization capacity of biochar can be explained by its porous structure, surface functional groups, pH greater than 7, and cation exchange capacity. However, the effectiveness in reducing metal bioavailability depends on the physicochemical characteristics of the biochar, which are strongly associated with the process conditions and feedstock. The aims of this study were to analyze the effect of pyrolysis temperature on the properties of biochars derived from different locally available biomass materials, biochar potential to adsorb Cr, and biochar phytotoxicity in seed germination. Poultry litter (PL), maize straw, the macrophyte Juncus imbricatus, and phytoremediation wastes from the macrophyte previously exposed to Cr were pyrolyzed into biochar at 300 °C and 600 °C. The properties and capacity of biochar to remove Cr from the aqueous phase were determined. Finally, a germination assay was performed to evaluate biochar phytotoxicity. Biochar yield decreased with increasing pyrolysis temperature, whereas ash content and pH increased. Biochar C content and total surface area increased with temperature. Biochar Cr removal capacity improved under the highest temperature, reaching a maximum sorption value of 13.7 mg g -1 Cr at 300 °C in PL biochar and of 42.6 mg g -1 Cr at 600 °C in J. imbricatus biochar. Despite the comparatively high metal content in the biochar, the germination indices of all biochars produced at 600 °C were higher than 80%, suggesting no phytotoxicity. Considering the metal sorption capacity and the phytotoxicity, biochars produced from J. imbricatus, PL, and phytoremediation residues at 600 °C were suitable for use in the removal of Cr from water. Integr Environ Assess Manag 2023;19:717-725. © 2022 SETAC., (© 2022 SETAC.)

Herein, a one-step co-pyrolysis protocol was adopted for the first time to prepare a novel pyrogenic carbon-Cu 0 /Fe 3 O 4 heteroatoms (FCBC) in CO 2 ambiance to discern the roles of each component in PDS activation. During co-pyrolysis, CO 2 catalyzed formation of reducing gases by biomass which facilitated reductive transformation of Fe 3+ and Cu 2+ to Cu 0 and Fe 3 O 4 , respectively. According to the analysis, the resulting metal (oxide) catalyzed graphitization of biocharand decomposition of volatile substances resulting in an unprecedented surface area (1240 m 2/ g). The resulting FCBC showed greater structural defects and less electrical impedance. Batch experiments indicated that Rhodamine B (RhB) degradation by FCBC (100%) was superior to Fe 3 O 4 (50%) and Cu 0 /Fe 3 O 4 (76.4%) in persulfate (PDS) system, which maintained reasonable efficiency (75.6%-63.6%) within three cycles. The reactive oxygen species (ROS) associated with RhB degradation was identified by an electron paramagnetic resonance and confirmed by scavenging experiments. RhB degradation invoked both (sulfate and dominantly hydroxyl) radical and non-radical (singlet oxygen, 1 O 2 ) pathways. Regarding FCBC, Cu 0 can continuously react with Fe 3+ in Fe 3 O 4 to generate larger quantities of Fe 2+ , and both Cu 0 and Fe 2+ activated PDS to yield sulfate radicals which was quickly converted to hydroxyl radical. Besides, Cu 0 /Cu 2+ could complex with PDS to form a metastable complex, which particularly contributed to 1 O 2 generation. These cascade reactions by FCBC were reinforced by carbonyl group of biochar and favorable electron transfer ability. This work highlighted a new approach to prepare a magnetic and environment-benign heterogonous catalyst to remove organic pollutants in water., (Copyright © 2021. Published by Elsevier B.V.)

The objective of current study is to explore the energy recovery potential of fermentation residues. In this perspective, pyrolysis characteristics, kinetics, and modified biochar derived from pine sawdust after fermentation (FPD) were determined, and comparison was established with pine sawdust (PD). The variation range of comprehensive pyrolysis index (CPI) values of FPD was found 6.51 × 10 -7 -16.38 × 10 -7 % 2 ·min -2 ·°C -3 , significantly higher than that of untreated samples determined under the same experimental conditions. The average activation energy of FPD was 367.95 kJ/mol, 389.45 kJ/mol, and 346.55 kJ/mol calculated by Flynn-Wall-Ozawa (FWO) method, Kissinger-Akahira-Sonuse (KAS), and Starink method respectively, and importantly, these values are much higher than those of PD. Additionally, fermentation could enhance the adsorption capacity for methylene blue of biochar from 0.76 mg/g to 1.6 mg/g due to the abundant surface functional groups and three-dimensional internal pore structure. The adsorption pattern of fermented pine wood shifted from chemisorption dominated to the synergetic adsorption of surface functional groups adsorption and intragranular filling. These results show that FPD has favorable pyrolytic properties, and the derived biochar has adsorption properties, which is the basis for designing pyrolysis process and reusing fermentation residues. HIGHLIGHTS: The FPD has higher values of CPI and activation energy than the PD. FPD-derived biochar has higher adsorption capacity than PD-derived biochar. The fermentation improves the pyrolysis performance. The fermentation enhances adsorption capacity due to unique structure of biochar., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In order to reduce the pyrolysis temperature during the process of directional conversion from kitchen waste (KW) into aromatic biochar, a kind of catalyst was prepared with carbon material coated with tri-metallic oxide (Fe 2 O 3 , MgO and Al 2 O 3 ) combining with sulfonic acid groups (CMO@SA) according to KW compositions. The aromaticity of KW pyrolysis biochar (KWB) increased when the temperature ranged from 170 to 210 °C. The catalytic pyrolysis temperature of KW reduced from 500 to 190 °C for biochar generation with similar aromaticity due to amendment of CMO@SA. The maximum adsorption capacity of catalytic pyrolysis KWB was 160.23 mg/g for dyeing wastewater, which was equivalent to biochar generated at 500 °C. The decrease of pyrolysis temperature was attributed to the reduction of bonds fracture activation-energy among CH, CC and CO under the catalytic function. The catalytic activity and recovery of CMO@SA kept at 92 % and 90 % after five recycle., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Agro-industrial wastes can be thermochemically converted to sustainable fuels and upcycled carbon products. However, processing such feedstocks through pyrolysis or hydrothermal carbonization (HTC) alone yields fuels that require significant downstream upgrading. In this work, apple pomace was treated via a cascaded HTC-pyrolysis process using inexpensive and abundant clay catalysts, montmorillonite and attapulgite. Clays were added pre-HTC to raw biomass or to hydrochar pre-pyrolysis to examine the effect of addition as a function of process insertion point. Both clays produce similar bio-oils when they are added at the same process point. However, bio-oil was affected by the point in which clay was added to the process (before or after HTC). When clay was added pre-HTC, the bio-oil had an average hydrocarbon content twice that when clay was added to the hydrochar after HTC, prior to pyrolysis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Over the years, the transformation of biomass into a plethora of renewable value-added products has been identified as a promising strategy to fulfil high energy demands, lower greenhouse gas emissions, and exploit under-utilized resources. Techno-economic analysis (TEA) and life-cycle assessment (LCA) are essential to scale up this process while lowering the conversion cost. In this study, trade-offs are made between economic, environmental, and technical indicators produced from these methodologies to better evaluate the commercialization potential of biomass pyrolysis. This research emphasizes the necessity of combining LCA and TEA variables to assess the performance of the early-stage technology and associated constraints. The important findings based on the LCA analysis imply that most of the studies reported in literature focussed on the global warming potentials (GWP) under environmental category by considering greenhouse gases (GHGs) as evaluation parameter, neglecting many other important environmental indices. In addition, the upstream and downstream processes play an important role in understanding the life cycle impacts of a biomass based biorefinery. Under upstream conditions, the use of a specific type of feedstock may influence the LCA conclusions and technical priority. Under downstream conditions, the product utilization as fuels in different energy backgrounds is crucial to the overall impact potentials of the pyrolysis systems. In view of the TEA analysis, investigations towards maximizing the yield of valuable co-products would play an important role in the commercialization of pyrolysis process. However, comprehensive research to compare the conventional, advanced, and emerging approaches of biomass pyrolysis from the economic perspective is currently not available in the literature., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The penicillin industry produces a large amount of penicillin mycelial dreg (PMD), potentially causing severe environmental problems without proper treatment and disposal. To achieve the goals of PMD management, the present work explored the potential of PMD as a novel feedstock to produce biochar with very high adsorption performance. PMD was pyrolyzed at 400-800 °C to prepare biochars (PMD-BCs), and the physical and chemical properties were characterized using various methods. The adsorption capacities of Pb 2+ on PMD-BC400, PMD-BC600, and PMD-BC800 were 37.04, 62.89, and 107.53 mg/g, respectively, at a temperature of 25 °C and pH of 5.0. The adsorption process of Pb 2+ on PMD-BCs can be well described by the Langmuir model and pseudo-second-order model. Mineral precipitation, ion exchange, functional group complexation and Pb 2+ -π interaction were involved in the adsorption of Pb 2+ on PMD-BCs. Moreover, mineral precipitation and ion exchange dominated Pb 2+ sorption on PMD-BCs (84.71-92.73%). This study indicates the transition of PMD to biochar for Pb 2+ adsorption is a promising method for PMD utilization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The sluggish Fe 3+ /Fe 2+ cycle was the rate-limiting step in the Fenton-like reaction, and metal-free carbonaceous materials are considered as emerging alternatives to solve this problem. However, the effect of carbon material properties on the distribution of reactive species remains poorly understood. This study investigated the possibility and mechanism of using biochar to accelerate the Fe 3+ /Fe 2+ cycle to overcome the low efficiency of Fe 3+ /persulfate (PS) catalytic oxidation of phenanthrene. More importantly, the contribution of reactive species in the reaction systems with the variation of biochar pyrolysis temperatures was quantitatively studied. The results showed that medium-temperature derived biochar (BC500) had the greatest ability to enhance the Fenton-like system compared to the low- and high-temperature (BC350/700), and the first-order rate constant achieved 5.2 and 35.7-fold increase against the biochar/PS and Fe 3+ /PS systems, respectively. Using electrochemical evidence, sulfoxide probe tests, and steady-state concentration calculations, radicals yields were found to rise and then reduce with decreasing pyrolysis temperature, while the nonradical contribution of Fe(IV) increased to 56.3%. Electron paramagnetic resonance, Boehm titration, and Raman spectroscopy unraveled that the enhanced effect of biochar resulted from itself persistent free radicals, phenolic-OH, and edge defects, which enabled electron transfer between Fe 3+ and biochar. Fe 2+ was thus continuously generated and effectively activated the PS. This work enables a better understanding of the Fe 3+ -mediated Fenton-like reaction in the presence of biochar and provides a sustainable green strategy for Fenton chemistry with potential applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The water hyacinth has been identified as a persistent threat to the pillars of sustainability, resulting in an increased demand for cost-effective mitigation measures. Existing control measures such as chemical and mechanical methods have proved ineffective and expensive, although their use in a biorefinery is deemed sustainable. The study focused on using the response surface methodology of Design-Expert to optimise process parameters, emphasising temperature and particle size, to improve the liquid fraction yield from the pyrolysis of water hyacinths. The experiment was conducted in the temperature range of 273.22 and 676.78 °C, with a particle size range of 380 and 2620 µm, and subjected to a heating rate of 30 °C/min and a nitrogen flow rate of 25 l/min. The results suggest that an increase in temperature and particle size led to a rise in the liquid fraction and a decrease in char. The liquid fraction increased from 24.36 wt.% at 273.22 °C to 48.45 wt.% at 575 °C and reduced to 25.56 wt.% at 626.78 °C. Char decreased from 58.21 to 33.84 wt.% at 626.78 °C. Given this, the quadratic model was found fit for optimisation. Statistical analysis of variance showed good agreement between actual data and the predicted model. This study argues that the valorisation of water hyacinths, if accompanied by policies and strategies, can trigger comprehensive socio-economic and environmental benefits by implementing optimum conditions to generate an improved liquid fraction that tends to influence its commercialisation. It is envisaged that the study's findings will inform policy discussions and formulation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pyrolysis of pharmaceutical sludge (PS) is a promising way of safe disposal and to recover energy and resources from waste. The resulting PS biochar (PSBC) is often used as adsorbent, but has seldom been explored as catalyst. Herein we demonstrate that PSBC (0.4 g/L) could efficiently activate peroxymonosulfate (PMS) to 100% degrade 4-chlorophenol (4-CP) with rate constants of 0.42-1.70 min -1 , outperforming other reported catalysts. Interestingly, the PMS activation pathway highly depended on PSBC pyrolysis temperature, which produced dominantly high-valent iron species (e.g., Fe IV O 2+ ) at low temperature but more sulfate radical (SO 4 ·- ) and hydroxyl radical (·OH) at higher temperature, e.g., 0.17, 0.23, 0.12 mmol/L of Fe IV O 2+ /·OH were produced within 10 min by PSBC-600/PMS, PSBC-800/PMS, and PSBC-1000/PMS, respectively. Characterization, density functional theory (DFT) simulation and Pearson correlation analysis revealed that along with the increase of pyrolysis temperatures, the active sites of PSBC gradually shifted from atomically dispersed N-coordinated Fe moieties (FeN 4 ·- /·OH were produced within 10 min by PSBC-600/PMS, PSBC-800/PMS, and PSBC-1000/PMS, respectively. Characterization, density functional theory (DFT) simulation and Pearson correlation analysis revealed that along with the increase of pyrolysis temperatures, the active sites of PSBC gradually shifted from atomically dispersed N-coordinated Fe moieties (FeN x ) to iron nitrides (Fe x N), which activated PMS to produce Fe IV O 2+ and SO 4 ·- /·OH, respectively. This study clarifies the structure-activity relationships of PSBC for PMS activation, and opens a new avenue for the treatment and utilization of PS as high value-added resources., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) analysis was used for the at-line sampling of pyrolytic vapors produced during the fast pyrolysis of biomass. The pure and binary blends of switchgrass (SWG) and pine harvest residues (PT6) were used as biomass feedstocks. Sequential SPME sampling allowed for monitoring of changes in the pyrolysis vapors as char accumulated in the fluid bed. The relative concentration and composition of the pyrolysis vapors desorbed from the SPME fibers were investigated using GC-MS, and the resulting chromatograms were analyzed using principal component analysis (PCA) to compare the composition of the pyrolysis vapors over the course of the pyrolysis run. The chemical compositions of both carbohydrate and lignin fragments varied as the char builds up in the reactor bed. Fragments derived from cellulose and hemicelluloses included anhydrosugars, furans, and light-oxygenated compounds. Lignin fragments included methoxyphenols, phenolic ketones, aldehydes, and low-molecular-weight aromatics. The composition of the carbohydrate fragments changed more than those of the lignin fragments as the char built up in the fluid bed. This combination of SPME-GC/MS-PCA was a novel, easy, and effective method for measuring the composition and changes in the composition of pyrolysis vapors during the fast pyrolysis process. This work also highlighted the effect of char build-up on the composition of the overall pyrolysis vapors.

This study was envisaged to understand the effect of increasing pyrolysis temperature on the Cr(VI) removal potential of the groundnut shells derived biochars. The biochars were prepared at four different pyrolysis temperatures (350 °C, 450 °C, 550 °C, 650 °C) and were used unmodified to examine the adsorption potential for Cr(VI). Influence of biochar dose (1-10 g/L), pH initial (2-10), Cr(VI) initial (10-500 mg/L) on Cr(VI) adsorptions; adsorption kinetics and isotherms were investigated. The observations suggested that the pyrolysis temperature is the key player in deciding the physicochemical properties as well the adsorption potential of the biochars. SEM and FTIR analysis suggested significant morphological and functional transformations in biochars with increasing pyrolysis temperature. The pH initial was found to be the most profound adsorption parameter determining the adsorption potential of the biochars. The Cr(VI) adsorption capacity of the biochars decreased with the increase of the pyrolysis temperature (142.87-31.25 mg/L) as well as the solution pH initial . All the biochars attained 100% removal efficiency with 50 mg/L of Cr(VI) initial and GNSB/350 achieved it in the minimum time (10 h) among all the biochars. GNSB/350 showed promising Langmuir adsorption capacity of 142.87 mg/L (pH 2, T adsorption 30 °C, Cr(VI) initial 10-500 mg/L). In addition, the adsorption mechanism was found to be a synergistic action of chemi/physi-sorption with monolayer adsorption. Hence, the pyrolysis temperature significantly altered the physicochemical properties of the biochars, which highly influenced the adsorption performance of biochars., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Different pyrolysis conditions determine the properties of the biochar. The properties of biochar may affect directly or indirectly their influence on living organisms. The aim of this study was to determine the toxicity of biochar obtained under different conditions (temperature: 500 or 700 °C, carrier gas: N 2 or CO 2 , feedstock: sewage sludge or sewage sludge/biomass mixture) after adding to the soil in long-term pot experiment (180 days). Biochars were added to the podzolic loamy sand at a 2% (w/w) dose. Samples were collected at the beginning of the experiment and after 30, 90 and 180 days. The bacteria Aliivibrio fischeri (luminescence inhibition - Microtox), the plant Lepidium sativum (root growth and germination inhibition test - Phytotoxkit F), and the invertebrate Folsomia candida (mortality and reproduction inhibition test - Collembolan test) were used as the test organisms. In the long-term perspective for most tests, changing the carrier gas from N 2 to CO 2 resulted in reduced toxicity of the biochar. A particularly beneficial effect of changing the gas to CO 2 was observed for the solid-phase test with L. sativum. The CO 2 during pyrolysis had the least beneficial effect on toxicity towards A. fischeri., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The pyrolysis of spent coffee grounds (SCG) and polymers was examined as a waste treatment option for energy recovery and carbon sequestration. Rice straw-derived biochar was used as control biochar to evaluate the sorption capacity and energy production capability of SCG-derived biochar. SCG are characterised by high levels of volatile matter, rendering them suitable as an energy source. SCG were converted to biochar, bio-oil, and syngas via pyrolysis, with yields of 22%, 33%, and 45%, respectively. The high heating value (HHV) of the biochar and bio-oil was 20.6 and 22.9 MJ kg -1 , respectively, indicating that they could be used as supplementary fuels. Co-pyrolysis with polymers (20 v v% -1 ) increased the HHV of biochar. Accordingly, the maximum production of CH 4 and H 2 increased from 0.3 and 0.04 mmol g -1 to 3.4-6.3 and 0.8-1.3 mmol g -1 , respectively. Polystyrene most strongly enhanced the yields of CH 4 and H 2 , followed by polypropylene and polyethylene; this order was likely to be in accordance with the number of carbon and hydrogen atoms present in the monomers. Similar to rice straw-derived biochar, the biochar produced from SCG demonstrated a high sorption capacity for 2,4-dinitrotoluene and chromate due to its high carbon content and anion exchange capacity, respectively. Laboratory pot tests revealed that the coffee grounds-derived biochar was able to increase the growth of young radish. Our results suggest that the pyrolysis of SCG and polymer may be a promising option for waste treatment, energy production, and carbon sequestration.

Sorption is considered a cost-effective technique for cadmium (Cd) removal from water, while the exhausted Cd-enriched sorbent should be properly disposed of. In this study, pyrolysis of exhausted hydrochar sorbent was conducted at 300-900 °C, and the behavior of Cd and the physicochemical properties and environmental applications of the regenerated biochar were investigated. The vaporization of adsorbed Cd in hydrochar was greatly enhanced by elevating pyrolysis temperature, and almost no Cd was observed in the regenerated biochars obtained at 700-900 °C. In comparison with the raw hydrochar, the regenerated biochars showed higher pH, ash content, and carbon content, while the contents of hydrogen and oxygen decreased. According to the toxicity characteristic leaching procedure result, the toxicity and mobility of Cd in hydrochar were greatly reduced after pyrolysis. Notably, the regenerated biochar showed much higher Cd sorption capacity (26.05-30.24 mg/g) than the raw hydrochar (6.70 mg/g). Surface complexation with oxygen-containing functional groups was the dominant Cd sorption mechanism for hydrochar, and precipitation between Cd 2+ and carbonates dominated the Cd removal by the regenerated biochars. These results illuminated that pyrolysis can be an effective technique for the harmless disposal of exhausted hydrochar sorbent and the regeneration of valuable biochar., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The migration of extracellular antibiotic resistance genes (eARGs) in porous media is an important pathway for ARGs to spread to the subsoil and aquifer. Biochar (BC) has been widely used to reduce the mobility of soil contaminants, however, its effect on the mobility of eARGs in porous media and the mechanisms are largely unknown. Herein, the effects of BCs synthesized from wheat straw and corn straw at two pyrolysis temperatures (300 °C and 700 °C) on the transport of plasmids-carried eARGs in sand column were investigated. The BC amendments all significantly decreased the mobility of eARGs in the porous medium, but the mechanism varied with pyrolysis temperature. The higher temperature BCs had a stronger irreversible adsorption of plasmids and greatly enhanced the attachment and straining effects on plasmids during transport, thus more effectively inhibited the mobility of eARGs. The lower temperature BCs had weaker adsorption, attachment, and straining effects on plasmids, but induced generation of hydroxyl radicals in the porous medium and thereby fragmented the plasmids and hindered the amplification of eARGs. These findings are of fundamental significance for the potential application of BC in controlling the vertical spread of eARGs in soil and vadose zones., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Biochar has been regarded as an effective amendment for soil carbon sequestration and soil quality improvement. However, it remains unclear how pyrolysis temperature and biochar aging impact the responses of soil properties and CO 2 emissions to biochar addition. Here, we investigated the effect of biochar on soil properties and CO 2 emissions in a laboratory incubation using soils amended with/without fresh biochar produced at 300 (BC300), 450 (BC450), and 600 °C (BC600) and their corresponding naturally aged samples (aged in soil for 360 days). The results showed that biochar significantly increased soil total nitrogen (by 8-36%), available phosphorus (by 19-69%) and available potassium (by 1.5-4.2-fold) throughout the incubation. Both fresh and aged biochar promoted the formation of soil macroaggregate at the end of the incubation. Moreover, fresh and aged BC300 increased the soil dissolved organic matter (DOM) content, whereas for BC450 and BC600, at the beginning, the content of soil DOM was reduced, but the effects finally became insignificant. Generally, fresh biochar had no significant effect on soil enzyme activities and soil bacterial richness and diversity, but an inhibitory effect occurred in the aged samples. Both fresh and aged BC300 increased soil CO 2 emissions, which was due to the biochar-induced increase in soil DOM content and enrichment of copiotrophic bacteria (Proteobacteria) as well as the decline of oligotrophic bacteria (Acidobacteriota). A significant decrease in soil CO 2 emissions was observed after fresh BC450 and BC600 addition, owing to the biochar-induced decline in soil DOM content, while an opposite trend was found in aged samples, which could be attributed to the shift of the dominant soil phylum from Acidobacteriota to Proteobacteria. These findings enhance our understanding of biochar's potential to improve soil quality and sequester soil carbon., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Biochars have been highlighted as a means of carbon sequestration, which is significant for achieving carbon neutrality. Mixtures of wood chips and either bentonite or kaolin were co-pyrolysed at temperatures of 350 °C and 550 °C, and the microstructural characteristics and the carbon sequestration potential of the resultant biochar were explored in the study. The addition of minerals promoted the formation of a stable carbon structure in biochar, especially the proportion of SiC bonds in the high-temperature mineral-composited biochar increased by 3.56-3.82 times compared with the original biochar. After bentonite or kaolin was added to wood chips pyrolysed at 550 °C, the carbon loss after H 2 O 2 oxidation was reduced to no more than 19.2%, and the Recalcitrance Index (R 50 ) of biochar increased to no less than 0.89. The combined action of high temperature and minerals promoted the formation of highly aromatic structures of biochar (H:C < 0.4) and reduced the amount of dissolved organic carbon to 4.89 mg g -1 . Furthermore, minerals directly covered the surface of biochar, and the content of SiC bond increased, thus strengthening the chemical and thermal stability of biochar. However, the addition of minerals had no significant effect on the biological stability of biochar. The study indicates that the pre-pyrolysis mineral addition is an effective way to increase the carbon sequestration potential of biochar., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The aim of this work was to study on MgO-modified KOH activated biochar (AC) catalysts, in the pyrolysis of sawdust for the direct production of bio-jet fuels using a tandem micro-pyrolyzer. AC catalysts with various MgO contents (5 to 20 wt%) were synthesized using an impregnation method. The mesopores generated (4 to 18 nm) in the carbon has a great potential in the conversion of oxygenated to jet fuel. The importance of basic nature in the catalysts is demonstrated with the maximum bio-jet fuel yield of 29 % at 10 % MgO. Further, the temperature of 600 °C and a catalyst/sawdust ratio of 10 are identified as the optimal conditions. The nanosize of MgO and the synergism of acid and base sites seemed to enhance deoxygenation, via decarboxylation and decarbonylation, and oligomerization, which are required for jet fuel formation in high amounts from sawdust pyrolysis., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In this study, nitrogen self-doping layered graphitic biochar (Na-BC900) was prepared by catalytic pyrolysis of lotus leaves at 900  ° C, in the presence of NaCl catalyst, for peroxydisulfate (PDS) activation and sulfamethoxazole (SMX) degradation. NaCl as catalyst played a crucial part in the preparation of Na-BC900 and could be reused. The SMX degradation rate in Na-BC900/PDS system was 12 times higher than that in un-modified biochar (BC900)/PDS system. The excellent performance of Na-BC900 for PDS activation was attributed to its large specific surface areas (SSAs), the enhanced graphitization structure and the high graphitic N content. The quenching and electrochemical experiments, electron paramagnetic resonance (EPR) studies inferred that the radicals included SO 4 •- , • OH, O 2 •- and biochar mediated electron migration. Both radical and non-radical mechanisms contributed to the removal of SMX. Additionally, this catalytic pyrolysis strategy was clarified to be scalable, which can be applied to produce multiple biomass-based biochar catalysts for restoration of polluted water bodies.1 O 2 and biochar mediated electron migration. Both radical and non-radical mechanisms contributed to the removal of SMX. Additionally, this catalytic pyrolysis strategy was clarified to be scalable, which can be applied to produce multiple biomass-based biochar catalysts for restoration of polluted water bodies., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Agricultural and food waste have become major issue affecting the environment and climate owing to growing population. However, such wastes have potential to produce renewable fuels which will help to meet energy demands. Numerous valorization pathways like anaerobic digestion, pyrolysis, composting and landfilling have been employed for treating such wastes. However, it requires integrated system that could utilize waste and promote circular bioeconomy. This review explores integration of anaerobic digestion and pyrolysis for treating agricultural and food waste. Proposed system examines the production of biochar and pyro-oil by pyrolysis of digestate. The use of this biochar for stabilizing anaerobic digestion process, biogas purification and soil amendment will promote the circular bioeconomy. Kinetic models and framework of techno-economic analysis of system were discussed and knowledge gaps have been identified for future research. This system will provide sustainable approach and offer carbon capture and storage in form of biochar in soil., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Metals discharged from abandoned mines are a major source of pollution in many parts of the world. As a result, there is a growing need for suitable low-cost remediation methods. While a large literature base exists demonstrating the efficacy of biochar to remove metals from solution, most studies are confined to the laboratory. This study examines the effects on the biochar quality when scaling up production from laboratory to pilot scale. Pilot scale biochars were produced using a 600 kg batch pyrolysis reactor, these chars were then deployed in the field using a series of 100 mm × 1200 mm cylindrical treatment cells installed at the point of discharge from an abandoned mine site. Most biochars produced at a pilot removed more zinc under laboratory conditions, however all of the biochars showed a reduced performance when tested in the field, this ranged from a 14% to an 85% reduction depending on the biochar., (Crown Copyright © 2022. Published by Elsevier Ltd. All rights reserved.)

Presently, as the prevalent pyrolysis atmospheres, N 2 is widely used, while air-limitation and CO 2 are rarely considered, to produce biochar to adsorb tetracycline. This study thus used N 2 , CO 2 , and air-limitation to produce various biochars at 300 ∼ 750 °C, and explored their structure-performance relationship for tetracycline sorption. The maximum sorption capacities of biochars produced in CO 2 and air-limitation were 55.36 mg/g and 71.11 mg/g (at 750 °C), respectively, being 2.34 and 3.01 times that of biochars produced in N 2 (23.60 mg/g at 750 °C). Interestingly, except for high pore volume and specific surface area supported pore filling and sites providing effect, ash (containing metal cations, P-O, and S=O) induced complexing effect was the primary mechanism for tetracycline sorption, rather than hydrophobic effect, π-π interaction, and hydrogen bond caused by C composition. This study provides important information about adjusting the pyrolysis atmosphere to improve the sorption performance of biochar toward tetracycline., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The blooming of beach-cast seaweed has caused environmental degradation in some coastal regions. Therefore, a proper treating and utilizing method of beach-cast seaweed is demanded. This study investigated the potential of producing power or biofuel from pyrolysis of beach-cast seaweed and the effect of the ash-washing process. First, the raw and washed beach-cast seaweeds (RS and WS) were prepared. Thereafter, thermogravimetric analysis (TG), bench-scale pyrolysis experiment, process simulation, and life cycle assessment (LCA) were conducted. The TG results showed that the activation energies of thermal decomposition of the main organic contents of RS and WS were 44.23 and 58.45 kJ/mol, respectively. Three peak temperatures of 400, 500, and 600 °C were used in the bench-scale pyrolysis experiments of WS. The 600 °C case yielded the most desirable gas and liquid products. The bench-scale pyrolysis experiment of RS was conducted at 600 °C as well. Also, an LCA was conducted based on the simulation result of 600 °C pyrolysis of WS. The further process simulation and LCA results show that compare to producing liquid biofuel and syngas, a process designed for electricity production is most favored. It was estimated that treating 1 ton of dry WS can result in a negative cumulative energy demand of -2.98 GJ and carbon emissions of -790.89 kg CO 2 equivalence., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Furfural residue (FR) is a solid waste generated during the production of furfural from corn cobs. The chemical energy and material potential of FR can be potentially recovered via pyrolysis. In this study, the pyrolysis of FR at the temperature ranging from 350 to 650 °C at the varied heating rate was investigated, aiming to understand the characteristics of the pyrolysis products. The results indicate that the organic components of FR tend to be cracked to form biochar and gases as the dominate products, due to the high ash content of FR. The FR-derived bio-oil also contained abundant organics derived from cellulose and lignin. Increasing pyrolysis temperature favored formation of the organics with fused ring structures. Lower heating rate in pyrolysis also formed biochar with higher thermal stability and higher fixed carbon content by enhancing the extent of deoxygenation. Additionally, the transformation of -OH via dehydration, -C-H into = C-H via dehydrogenation, and the cracking of CO during carbonization of biochar in the pyrolysis were also observed during pyrolysis of FR. Activation of the FR-derived biochar generated abundant micropores and mesopores, rendering the activated carbon with superior specific capacitance as electrodes of electrocapacitors (329 Fg -1 ) and the excellent adsorption efficiency of phosphate (up to 98.81%)., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

It is inevitable that reclaimed cotton stalks will contain a certain amount of plastic film due to the wide application of plastic mulching during the process of cotton cultivation, and this makes it inappropriate to return it to the field or for it to be processed into silage. In this study, biochars were prepared by the co-pyrolysis of cotton stalk with low-density polyethylene (LDPE) in the proportions of 1:0, 3:1, 2:1, and 1:1 ( w / w ) at 400 °C, 450 °C, and 500 °C and maintaining them for 1 h. The effects of the co-pyrolysis of cotton stalk with LDPE on the properties of biochars (e.g., pH, yield, elemental analysis, specific surface area, etc.) and the Pb(II) removal capacity were analyzed. Co-pyrolysis cotton stalks with LDPE could delay the decomposition of LDPE but could promote the decomposition of cotton stalk. At 400 °C and 450 °C, the addition of LDPE decreased the H/C ratio, while no significant difference was found between the pristine biochar and the blended biochar pyrolyzed at 500 °C. An FTIR analysis indicated that the surface functional groups of biochar were not affected by the addition of LDPE, except for CH 3 and CH 2 . The results of the SEM showed that LDPE could cover the surface of biochar when pyrolyzed at 400 °C, while many macropores were found in the blended biochar that was pyrolyzed at 450 °C and 500 °C, thus increasing its surface area. The blended biochar that was pyrolyzed at 500 °C was more effective in the removal of Pb(II) than the cotton-stalk-derived biochar, which was dominated by monolayer adsorption with a maximum adsorption capacity of approximately 200 mg·g -1 . These results suggested that the co-pyrolysis of cotton stalks and LDPE may be used to produce biochar, which is a cost-effective adsorbent for heavy metal removal from aqueous solutions.

The pyrolysis characteristics of cadmium (Cd)-impregnated cellulose, hemicellulose, and lignin were studied to elucidate the pyrolysis velocity and deoxygenation characteristics of Cd-contaminated rice straw. The results show that Cd significantly affects the pyrolysis characteristics of a single biomass component. With a heating rate of 5 °C·min -1 and a Cd loading of 5%, the initial pyrolysis temperature of cellulose and hemicellulose decreases while that of lignin increases. The maximum pyrolysis velocity of cellulose, hemicellulose, and lignin is decreased by 36.6%, 12.4%, and 15.2%, respectively. Cd increases the pyrolysis activation energy of the three components and inhibits their deoxygenation. For the pyrolysis of Cd-contaminated rice straw, both the initial depolymerization temperature and the pyrolysis velocity of hemicellulose is reduced, while the pyrolysis velocity of cellulose is accordingly increased. When Cd loading amplifies to 0.1%, 1%, and 5%, the maximum pyrolysis velocity of hemicellulose is decreased by 7.2%, 10.5%, and 21.3%, while that of cellulose is increased by 8.4%, 62.1%, and 97.3%, respectively. Cd reduces the release of volatiles and gas from rice straw, such as CO 2 , CO, and oxygen-containing organics, which retains more oxygen and components in the solid fraction. This research suggested that Cd retards the pyrolysis velocity and deoxygenation of rice straw, being therefore beneficial to obtaining more biochar.

In recent years, biomass has been reported to obtain a wide range of value-added products. Biochar can be obtained by heating biomass, which aids in carbon sinks, soil amendments, resource recovery, and water retention. Microwave technology stands out among various biomass heating technologies not only for its effectiveness in biomass pyrolysis for the production of biochar and biofuel but also for its speed, volumetrics, selectivity, and efficiency. The features of microwave-assisted biomass pyrolysis and biochar are briefly reviewed in this paper. An informative comparison has been drawn between microwave-assisted pyrolysis and conventional pyrolysis. It focuses mainly on technological and economic scenario of biochar production and environmental impacts of using biochar. This source of knowledge would aid in the exploration of new possibilities and scope for employing microwave-assisted pyrolysis technology to produce biochar., (Copyright © 2022 Elsevier Ltd. All rights reserved.)