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Carbonaceous catalysts obtained from agricultural residue could have potential in the production of biofuels such as biodiesel. This review paper discusses the preparation conditions (temperature, heating rate, hold time, inert gas flow rate, etc play key roles in development of textural characteristics of the catalysts) and functionalization methods of biochar and activated carbon derived from agricultural residues and their application to produce biodiesel. Research works reported in achieving maximum yield of biodiesel in terms of variable precursors, alcohol-to-oil ratio, reaction time and temperatures have been profoundly tabulated. Effect of textural properties of the biochar and activated carbon (such as surface area, total pore volume, average pore size, and functional group attached with the catalyst) on the biodiesel yield are examined. Studies on Regeneration and reusing of the spent catalysts are carefully inspected. The economic evaluation studies for the biochar and activated carbon and the applications of these for biodiesel production are scrutinized. Finally, the strategies to increase biomass and catalyst productivity, future prospect and research directions to enhance biofuel/biodiesel production and for the development of biochar and activated carbon from agricultural residues for sustainable biodiesel production is suggested. [Display omitted] • Preparation methods of biochar & activated carbon (AC) from AR examined. • Reaction conditions and mechanisms for biodiesel synthesis discussed. • Biodiesel yield correlated with surface area, pore volume & pore size of catalysts. • Regeneration & recycling of biochar & AC catalysts discussed for biodiesel yield. • Economic studies for biochar & AC production & application for biodiesel covered. [ABSTRACT FROM AUTHOR]

[Display omitted] • ML effectively predicted specific surface area and capacitance retention. • ML predicted corn straw as the best raw material. • Co-doping and freeze-drying control the pore structure of materials. • A corn-straw-based biochar was prepared for energy storage. The rapid screening of agricultural waste materials for capacitor preparation holds significant importance in comprehending the relationship between material properties and enhancing experimental efficiency. In this study, we developed two machine learning models to predict electrode material characteristics using 2997 data points extracted from 235 articles. The identification and influence of key features on prediction indices provide a theoretical foundation for subsequent practical preparation. Through regression analysis and index evaluation, corn straw emerged as the optimal material for capacitor preparation, leading us to propose a one-step activation and two-step modification approach to convert corn straw into porous biochar. By modifying biochar with Co(NO 3) 2 ·6H 2 O, the maximum electrode capacitance of porous carbon reached 732.6 F/g. Furthermore, the electrode exhibited exceptional cycle stability with a remaining capacitance of 96 % after 5000 cycles. The prepared symmetric capacitor demonstrated pseudocapacitance behavior with a capacitance of 183.15 F/g at a current density of 1.0 A/g, power density of 22 kW/kg, and energy density of 9.03 Wh/kg. Considering the increasing annual output of corn straw and its superior industrial application prospects compared to acid-, base-, or precious metal-based alternatives due to their cost-effectiveness and environmental friendliness, these findings highlight the potential practical value in utilizing modified corn straw biochar as an efficient energy storage electrode material. [ABSTRACT FROM AUTHOR]

[Display omitted] • Various K-enriched biochars were produced from Canna indica by pyrolysis. • Co-pyrolysis with bentonite promoted the transformation of K to exchangeable K. • Co-pyrolysis and pelleting enhanced the K slow-release potential of biochars. Potassium (K) is one of the essential macronutrients for plant growth, while most agricultural soils are suffering from K deficiency worldwide. Therefore, it is a promising strategy to prepare K-enriched biochar from biomass waste. In this study, various K-enriched biochars were prepared from Canna indica at 300–700 °C by pyrolysis, co-pyrolysis with bentonite, and pelletizing-co-pyrolysis. The chemical speciation and release behaviors of K were investigated. The derived biochars showed high yields, pH values, and mineral contents, which were affected by the pyrolysis temperatures and techniques. The derived biochars contained a significant amount of K (161.3–235.7 mg/g), which was much higher than the biochars derived from agricultural residues and wood. Water-soluble K was the dominant K species in biochars with a proportion of 92.7–96.0%, and co-pyrolysis and pelletizing promoted the transformation of K to the exchangeable K and K silicates. In comparison with the C. indica derived biochars (83.3–98.0%), the bentonite-modified biochar showed a lower cumulative release proportion of K (72.5% and 72.6%) in a 28-day release test, meeting the Chinese National Standard for slow-release fertilizers. In addition, the pseudo-first order, pseudo-second order, and Elovich models well described the K release data of the powdery biochars, and the pseudo-second order model was the best fit for the biochar pellets. The modeling results indicated that the K release rate decreased after the addition of bentonite and pelletizing. These results indicated that the biochars derived from C. indica could be used as potential slow-release K fertilizers for agricultural application. [ABSTRACT FROM AUTHOR]

• Biochars (BCs) were produced by pyrolysis of potato or raspberry stems at 600 °C. • They are effective adsorbents in the systems containing two different impurities. • Dissolved organic carbon of BCs was composed of aromatic substances of large weight. • The examined biochars showed satisfactory potential for environmental remediation. This paper presents a method of agricultural waste management — the production of two biochars (BC) from potato and raspberry stems. It defines the potential of these materials for remediation of degraded water and soil environments. The performed study included analyses of BC physicochemistry, dissolved organic carbon (DOC) release and ability to immobilize copper (Cu), tetracycline (TC) and carboxin (CB) in one- and two-adsorbate systems. The BCs were obtained with pyrolysis at 600 °C for 30 min in a nitrogen atmosphere. Their DOC was predominantly constituted of substances with large molecular weights and high aromaticity, meaning that both BCs can be safely applied as soil additives. Potato-biochar (P-BC) had a more developed surface than raspberry-biochar (R-BC). The specific surface area (S BET) of P-BC was 122 m2/g, whilst of R-BC was 87 m2/g. As a result, the efficiency of impurity adsorption in the one-adsorbate systems was higher for P-BC (61.75% for Cu, 73.84% for TC, and 54.43% for CB). In the two-adsorbate systems, organic impurities improved the immobilization of heavy metal ions on BCs. The efficiency of Cu adsorption on P-BC when TC was present was 88.29%. Desorption of Cu from BC was highest using HCl, whilst that of TC and CB was highest using NaOH. Maximum desorption was observed in a two-adsorbate system with TC + CB (up to 63.6% for TC). These results confirmed that potato and raspberry stems can be used to produce highly effective BCs with large application potential, especially for remediation of degraded soils and polluted waters. [ABSTRACT FROM AUTHOR]

A cathodic metal-based catalyst in a microbial fuel cell (MFCs) is costly so alternative carbon-based materials, such as biochar, are favored. Biochar that is obtained from agricultural waste (peanut husks) was combined with high-conductivity conductive carbon black (CCB) to form a cathodic composite catalyst (biochar/CCB). The optimal ratio of biochar/CCB (70% over 30%) and its volume (4.45 cm3) were obtained by response surface methodology (RSM). A cathode catalyst with low resistance (55.1 Ω) and a high reduction peak current (7.26 μA) was developed with an overall regression model explanatory power (R2) >0.95. Following the optimal biochar/CCB modification, the removal efficiency, voltage output, power density and Coulombic efficiency of the MFC were 6.91–21.6%, 1.82, 2.47 and 2.56 times higher, respectively, than those of a carbon MFC without a catalyst. The microbial community of the anode indicates that the cathode modified by biochar/CCB can promote the growth of electrogenic and degrading bacteria to achieve improved power production and pollutant removal efficiency. This result demonstrates that the optimized biochar/CCB in this study has great potential for subsequent use in pollutant treatment and power generation systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Removal of emerging contaminants such as pesticides from aqueous systems is of growing concern. The usage of sustainable materials as adsorbents is an eco-friendly approach to water purification. Sugarcane bagasse is an abundant waste material that can serve as a sustainable source for preparing adsorbents. This work investigated the removal of chlorpyrifos from aqueous systems using a composite adsorbent prepared from sugarcane bagasse-derived biochar and encapsulated in alginate. The batch studies were conducted to examine the effect of contact time, initial pH, initial concentration of adsorbate, sorbent dosage and temperature on the extent of chlorpyrifos removal by biochar alginate beads. Adsorption thermodynamics, equilibrium isotherms, and kinetics were studied to elucidate the chlorpyrifos uptake phenomenon. The error functions were used to determine model parameters using non-linear regression approach. Biochar alginate beads showed 86 % chlorpyrifos removal under optimized conditions. The adsorption capacity was found to be 6.25 mg g−1 for pH 10 at 10 ppm chlorpyrifos concentration. The analysis of experimental isotherm data revealed Freundlich isotherm model to be the best fitting with regression coefficient value of 0.9332 Kinetic studies showed that adsorption followed intraparticle diffusion model with R2 value of 0.9750, where Boyd model was further studied to confirm rate constant. Adsorption of chlorpyrifos onto biochar beads is showed to be exothermic with type of adsorption to be physisorption. • Agricultural waste sugarcane bagasse is utilized for preparation of biochar. • Biochar alginate beads are synthesized for removal of chlorpyrifos. • Adsorption of chlorpyrifos pursues Freundlich isotherm model and intra particle diffusion. • Chlorpyrifos removal efficiency of 86 % is observed under optimal conditions. [ABSTRACT FROM AUTHOR]

Molecular compounds present in biochar carbon structure are studied from biochar produced from forest, food, and agricultural wastes and sewage sludge using pyrolysis gas chromatography mass spectrometry (Py-GC/MS). The results show that with increasing biochar production temperature (PT), the total pyrolysis yield decreases, and the macromolecular structure becomes more condensed with the aromatic linkages becoming less alkylated, hence indicating a stable carbon structure. These highly stable biochar samples consist predominantly of inertinite and have the entire random reflectance (R o) distributions above the inertinite benchmark (IBR o 2%). The results are aligned with high carbon stability of high-temperature biochar. In contrast, biochar samples that were insufficiently carbonized and comprised of mainly semi-inertinitic biochar contain alkane traces, volatile compounds, and higher degrees of alkylation with aromatic linkages in their molecular structure. This indicates the more proneness to oxidative and microbial breakdown, and therefore a less condensed and less stable carbon structure. Additionally, occurrence of these compounds in inertinitic biochar indicate retention of free hydrocarbons within the biochar carbon structure. Complimenting microscopic and bulk geochemical data, Py-GC/MS data is additionally advantageous to assess the stability conditions of the biochar samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-composting improves the quality of the final product. • Addition of beef bone biochar reduced the available nutrients in vermicompost. • Membrane covered composting promotes lignin degradation in subsequent stages. • The best treatments have excellent properties that facilitate their application. • Membrane-covered compost synergized with biochar promotes earthworm growth. The sustainable management of agricultural waste is essential for curtailing environmental contamination. To address the shortcomings of single treatment methods, this study evaluated the feasibility of combining membrane-covered composting (MC) with vermicomposting. Based on this, the integrated effects of different biochar addition strategies on the combined process were investigated. The aim was to improve the efficiency of vermicomposting while eliminating the negative effects of biochar on earthworms. Addition of biochar before membrane-covered composting increased total earthworm biomass by 25.6 − 31.4 % and reproduction rate by 13.4 − 23.9 %. Specifically, the electrical conductivity (EC) (1061.0 − 1112.0 uS/cm) of the vermicompost was significantly reduced, while the total nutrient content (42.3 − 42.6 mg/g) and germination index (GI) (103.9 − 108.4 %) were maximized. Additionally, reductions in the carbon-to-nitrogen ratio and volatile content were observed. Overall, combination process is a promising approach to improve the quality of vermicomposting. The study's results offer a novel perspective on the value-added treatment of agricultural waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar added at the beginning of composting reduced 55% of total N 2 O emission. • N 2 O emission showed significant relationships with most environmental factors. • Biochar mitigated N 2 O mainly by regulating the physicochemical properties of compost. • Genes and enzymes influenced the overall effect of environmental factors to N 2 O. The effects and mitigation mechanisms of biochar added at different composting stages on N 2 O emission were investigated. Four treatments were set as follows: CK: control, B B10% : +10 % biochar at beginning of composting, B B5%&T5% : +5% biochar at beginning and + 5 % biochar after thermophilic stage of composting, B T10% : +10 % after thermophilic stage of composting. Results showed that treatment B B10% , B B5%&T5% , and B T10% reduced total N 2 O emissions by 55 %, 37 %, and 36 %, respectively. N 2 O emission was closely related to most physicochemical properties, while it was only related to amoA gene and hydroxylamine oxidoreductase. Different addition strategies of biochar changed the contributions of physicochemical properties, functional genes and enzymes to N 2 O emission. Organic matter and C/N contributed 23.7 % and 27.6 % of variations in functional gene abundances (P < 0.05), respectively. pH and C/N (P < 0.05) contributed 37.3 % and 17.3 % of variations in functional enzyme activities. These findings provided valuable insights into mitigating N 2 O emissions during composting. [ABSTRACT FROM AUTHOR]

In this study, a green and economically efficient adsorbent was prepared from discarded longan seed. Hydrochloric acid-modified longan seed biochar (HNSB), as the final product, possesses excellent adsorption properties. BET characterization of HNSB demonstrates impressive porous properties with a specific surface area of 420.58 m2/g. Batch adsorption experiments were conducted with gatifloxacin (GAT), norfloxacin (NOR), and lomefloxacin (LOM) as representatives of typical fluoroquinolone antibiotics (FQs). The adsorption capacity of HNSB for FQs exceeded 40% of that of commercial activated carbon. The sustained effective time of HNSB dynamic adsorption for treating high concentrations of FQs wastewater was more than 20 h. Adsorption kinetics and isotherms were fitted by the pseudo-second-order model and the Langmuir model. The adsorption mechanism includes the pore-filling effect, electrostatic attraction, reduction reaction, hydrogen bonding, π-π interaction, and hydrophobicity. This study provides an economic and feasible strategy for the engineering application of agricultural wastes in pharmaceutical wastewater treatment. [Display omitted] • Hydrochloric acid-modified longan seed biochar (HNSB) was produced as a green and economically adsorbent. • HNSB has a high specific surface area of 420.58 m2/g. • HNSB can effectively treat high concentrations of FQs wastewater for more than 20 h. • The adsorption capacity of HNSB for FQs exceeded 40% of that of commercial activated carbon. • Adsorption mechanism by a combination of pore filling, π-π interaction, reduction, hydrogen bonding and hydrophobic effects. [ABSTRACT FROM AUTHOR]

The importance of combating the contamination of water resources with emerging pollutants must be kept all the more in view by scientists, since such pollutants are harmful and pose challenges for traditional water treatment methods. The current study was designed to scrutinize the adsorption properties of a low-cost biochar for two pharmaceuticals in both single and binary systems. The work was focused on understanding how paracetamol (PARA) and diclofenac (DIC) co-adsorb, and it can serve as a beacon for similar studies, especially in modeling the adsorption processes of such systems. Using a low-cost biochar from pepper stem (PS) with a high surface area = 727.5 m2/g as adsorbent, experiments were carried out in both the single and binary systems to investigate the adsorption behavior of the mentioned pharmaceuticals. Results showed that, in the single system, the PS biochar demonstrates a slightly greater adsorption capability for both PARA and DIC, with a capacity of 354.66 and 256.10 mg/g, respectively, compared to its capacity for each pharmaceutical in the presence of the other in the solution. Interestingly, the effect of the presence of one of the pharmaceuticals on the thermodynamic parameters (ΔGº, ΔSº, and ΔHº) of the other was ignorable, and interactions such as hydrogen bonding, π-π, n-π, and anion-π interactions were at work for the adsorption processes, with different extends in each pharmaceutical-biochar case. On the other hand, the presence of one of the pharmaceuticals was effective on the kinetics of the adsorption process of the other and caused a decrease in its adsorption rate, especially in the initial stage of the process. Overall, in addition to the suitability of pepper stem biochar for PARA and DIC, results showed that the presence of one pharmaceutical is not influential on all the adsorption properties of the other, and the results can be exploited for studding similar systems. [Display omitted] • The adsorption properties of a low-cost biochar for two pharmaceuticals were scrutinized. • The capacity of biochar for each pharmaceutical was depended on the adsorption mechanism. • The effect of presence of one of the pharmaceuticals on thermodynamics of the other was ignorable. • Kinetic and isothermal properties were different in single and binary systems. • The results can be exploited as a beacon for studding similar systems. [ABSTRACT FROM AUTHOR]

Sunflower seed husk is a common oil crop by-product. In this study, the husk was used as a base material for preparing a new catalyst, referred to as Fe-Cu-biochar-MOFs. The new material was characterized by multiple nanoscale metal clusters with rough surfaces and irregular shapes, thus providing abundant reactive surface area and sites. The catalytic reactivity was tested using sulfadiazine (SDZ) through batch kinetic experiments, where Fe-Cu-biochar-MOFs were used to activate peroxydisulfate (PDS). The results indicate that the system was able to degrade 95.9% of SDZ within 60 minutes. Mechanistic investigations revealed that the presence of PDS converted Fe0 to Fe2+ and Cu0 to Cu+ in the Fe-Cu-biochar-MOFs, and the resulting Fe(Ⅱ) and Cu(I) ions facilitated the activation of PDS, resulting in abundant reactive oxygen species (1O 2 , SO 4 ∙ − and ∙ OH). This work provides a new approach of using waste agricultural by-products for the removal of environmental pollutants. [Display omitted] • FeCu-BC were obtained through facile one-pot synthesis and pyrolysis. • The characteristic can be significantly affected by adding different amount of biochar. • FeCu-BC 0.25 /PDS systems displayed best removal performance in acidic and neutral circumstance. • The C O functional groups and Fe-Cu compounds facilitated the generation of reactive species. [ABSTRACT FROM AUTHOR]

High-quality biochars/activated carbons were prepared, optimizing individual parameters of energetically-save microwave pyrolysis (raw material loading - 20 vs. 60 g, nitrogen atmosphere - flow vs. batch, ZnCl 2 activation) from two agricultural wastes - corn cobs, red mombin seeds. Most promising carbons were examined for gaseous xylene adsorption and showed higher sorption capacity (∼250–475 mg xylene · g−1) than commercial carbon (∼214 mg xylene · g−1). ZnCl 2 activation of both raw materials reduces the fixed carbon content and increases volatiles in activated carbon, suggesting microwave pyrolysis of activated feedstock should take 25 min. While biochars are microporous materials with inhomogeneous low-surface mesopore/macropore network, activated carbons are highly microporous-mesoporous. ZnCl 2 activation of both raw materials contributes to formation of extensive high-surface mesopore network (with pore-size < 20 nm) and enlargement of micropore-size, but does not affect the micropore volume. ZnCl 2 activation increases H 2 and decreases CH 4 production. Microwave pyrolysis of larger raw material loading with ZnCl 2 leads to CO 2 increase. Best xylene adsorption capacity (475 mg xylene · g−1) was determined for activated carbon produced from 60 g loading of corn cobs in batch nitrogen atmosphere, showing the largest micropore volume, lowest surface polarity and medium rate of graphitization. Large micropore volume, low surface polarity and high rate of graphitization of carbon are xylene sorption capacity-determining factors. [Display omitted] • Microwave pyrolysis optimization of corn cobs and red mombin seeds was done. • Pyrolysis time shortened from hours to 15 min in flow and 20 min in batch of nitrogen. • Novel highly-microporous activated carbons investigated in xylene adsorption. • Promoted H 2 + CO 2 production by larger biomass loading and ZnCl 2. • Large micropore volume, low surface polarity, high rate of graphitization are key for xylene sorption. [ABSTRACT FROM AUTHOR]

In this study, lotus stem (LS), a natural, abundant, and underutilized aquatic agricultural waste, was used to prepare biochar (BC) as a potential adsorbent for sewage treatment. A two-step process for the production of LS based nitrogen-doped BC (NLBC) has been developed, involving low-temperature pyrolysis of LS and urea mixture, followed by high-temperature pyrolysis of the pre-carbonized BC via NaOH immersion technique. The two-step activation treatment not only can effectively maintain the structural integrity of LS, but contribute to exposing more active sites for effective adsorption of methylene blue (MB). The obtained NLBC possesses a large pore volume (0.997 cm3 g−1) and great specific surface area of 1478.93 m2 g−1, contributing to its maximum adsorption capacity of 2320.81 mg g−1 for MB. The behavior of MB adsorbed onto NLBC conforms to pseudo-second-order kinetics and Langmuir–Freundlich models. The adsorption capacity remains stable across a range of pH, varying salt concentrations, and cyclic repetitions. The adsorption mechanism was ascribed to the synergetic effects of pore filling, H-bonding, and electrostatic interaction through comparative analysis before and after adsorption. The results indicate that NLBC is an environmentally friendly, cost-effective, and efficient for dye-containing wastewater treatment. [Display omitted] • Lotus stem derived nitrogen-doped hierarchical biochar (NLBC) was prepared by two-step pyrolysis of urea/NaOH. • NLBC with surface areas of 1478.93 m2·g−1 exhibited high adsorption capacity of 2320.81 mg·g⁻¹ for MB. • NLBC showed excellent adsorption recyclability and stability. • The MB adsorption process of NLBC conformed to Langmuir–Freundlich model and pseudo-second-order kinetics. [ABSTRACT FROM AUTHOR]

Studies on the conversion of organic materials into biochar have been preferred due to the effectiveness of biochar. Aquatic ecosystems harbor a significant amount of organic biomass, much of which is transferred to terrestrial systems, but often remains as waste. In this study, Posidonia oceanica (PO), Halidrys siliquosa (HS), Ulva lactuca (UL), and Codium fragile (CF), commonly found as marine waste along coastlines globally, were used as feedstocks for biochar production under four different pyrolysis conditions. Several analyses were conducted to characterize both marine waste and biochar forms in order to evaluate their potential for agricultural applications. The results showed that marine wastes and biochars contain almost all the necessary nutrients required for plant nutrition in varying proportions. The CF feedstock has a higher nitrogen (N) content than other feedstocks, while the UL contains greater phosphorus (P), potassium (K), and magnesium (Mg). Additionally, the PO exhibits high calcium (Ca), boron (B), and manganese (Mn) contents. Carbon (C) content also varied significantly depending on the biochar production technique. Temperature had a greater influence than holding time on the disparities in the elemental composition of biochars. The pH values of all types of biochar increased with rising temperature. However, the electrical conductivity (EC) values of HS and PO biochars decreased with increasing temperature. The highest mean BET surface area was observed in PO biochars. However, UL biochar has the most significant proportional increase compared to the UL feedstock by 218 times. All characteristics determined for all materials (feedstock, biochar) were within acceptable limits for application to soil. In conclusion, both marine waste and biochar forms may be confidently used for agricultural purposes, particularly in soil applications, when considering the characterization parameters within the scope of this research. Additionally, supporting and developing these results with more comprehensive analysis and research would be more suitable to reveal the potential of these marine wastes for agricultural systems. [Display omitted] • Marine wastes and biochar forms may have the potential to be utilized for agricultural purposes. • Marine wastes and biochar forms may be a potential source of carbon for the soil, and they may improve soil properties. • The use of marine wastes for appropriate purposes may support the economy and environment. • Marine wastes and biochar forms may reduce the requirement for chemical fertilizers. • Marine wastes and biochar forms may be utilized as compost material. [ABSTRACT FROM AUTHOR]

Agricultural by-products of sesame are promising bioresources in food processing. This study extracted lignin from the by-products of sesame oil production, namely, the capsules and straw of black and white sesame. Using acid, alkali, and ethanol methods, 12 distinct lignins were obtained to prepare biochar, aiming to investigate both the structural characteristics of lignin-based biochar (LBB) and its ability to remove benzo[ a ]pyrene (BaP) from sesame oil. The results showed that white sesame straw was the most suitable raw material for preparing biochar. In terms of the preparation method, acid-extracted lignin biochar was more effective in removing BaP than alkaline or ethanol methods. Notably, WS-1LB (white sesame straw acid-extracted lignin biochar) exhibited the highest BaP adsorption efficiency (91.44 %) and the maximum specific surface area (1065.8187 m2/g), characterized by porous structures. The pseudo 2nd and Freundlich models were found to be the best fit for the adsorption kinetics and isotherms of BaP on LBB, respectively, suggesting that a multilayer adsorption process was dominant. The high adsorption of LBB mainly resulted from pore filling. This study provides an economical and highly efficient biochar adsorbent for the removal of BaP in oil. [Display omitted] • White sesame straw is the best raw material for preparing biochar. • White sesame straw acid lignin biochar has the highest removal rate of BaP. • The adsorption of BaP by LBB includes physical and chemical processes. [ABSTRACT FROM AUTHOR]

• No major difference was observed in biochars, regardless of auger scale. • Existing biochar research could be reproduced in other auger reactors. • Pyrolysis liquid composition highly depended on the vapor residence time. • Pyrolysis products from common agricultural wastes were compared. Several studies have addressed the potential biorefinery, through small-scale pyrolysis, of coffee silverskin (CSS), grape pomace (GP) and olive mill waste (OMW), which are respectively the main solid residues from coffee roasting, wine making and olive oil production processes. However, increasing the scale of reactor to bring these studies to an industrial level may affect the properties, and hence applications, of the resulting products. The aim of this study is therefore to perform pilot scale experiments to compare and verify the results of analytical study (TGA) and bench scale reactor runs, in order to understand the fundamental differences and create correlations between pyrolysis runs at different scales. To this end, pyrolysis liquids and biochars from the slow pyrolysis of CSS, GP and OMW, performed using different scale auger reactors (15 kg/h and 0.3 kg/h), have been analysed (TGA, pH, density, proximate and ultimate analyses, HHV, FTIR, GCMS) and compared. The results showed no major differences in biochars when the temperature and the solid residence time were fixed. However, regarding pyrolysis liquids, compounds from the lab reactor were more degraded than pilot plant ones, due to, in this case, the vapour residence time was longer. Regarding the properties of the pyrolysis products, GP 400 °C biochars showed the best properties for combustion; CSS biochars were especially rich in nitrogen, and 400 °C GP and OMW pyrolysis liquids showed the highest number of phenolics. Hence, this study is considered a first step towards industrial scale CSS, GP and OMW pyrolysis-based biorefinery. [ABSTRACT FROM AUTHOR]

This study investigated the effects of adding biochar, ferrous sulfate, and their combination during composting of pig manure mixed with straw to reduce the loss of carbon and nitrogen during agricultural waste composting. Four 100 L fermentation tank-scale experimental composting treatments were established: the additive-free control (CK), addition of 5% biochar (BC), addition of 5% ferrous sulfate (SF), and addition of 2.5% BC + 2.5% SF (BS). The transformation of carbon and nitrogen and the change characteristics of bacterial communities during composting of the four treatments were explored. BS significantly reduced NH 3 , N 2 O, CO 2 , and CH 4 emissions by 59.57%, 48.41%, 35.80%, and 32.25% compared with CK, respectively. The BS treatment showed lower carbon and nitrogen losses than the single additive treatment. BS treatment enhanced the diversity and richness of bacterial communities during composting. The redundancy and Pearson correlation analyses revealed that the composition of dominant species between treatments had significant differences in different compost periods (mesophile, thermophilic, and cooling periods). BS treatment significantly increased the abundance ratio of carbon sequestration and nitrogen retention communities, and it enhanced nutrient preservation by microbial metabolism. Therefore, the composite addition of biochar and ferrous sulfate is an effective method to reduce the loss of carbon and nitrogen during agricultural waste composting. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein, the aim was to develop an in-depth understanding of the kinetic behaviour of olive tree pruning residue (OTPR), an abundant agricultural waste, during pyrolysis. Thermal analysis at 1, 2, 4, 6 and 10 °C.min-' was performed using TGA-thermogravimetric analysis, with the results subsequently used to determine the OTPR's kinetic thermal breakdown behaviour. Furthermore, advanced kinetics and technology solutions (AKTS) thermo-kinetic tool was applied to investigate the kinetic behaviour of OTPR and to generate kinetic predictions for various heating configurations. Friedman's method was the main approach used to evaluate the kinetic parameters. For comparison, other established kinetic modelling techniques, such as ASTM-E698 and Flynn-Wall-Ozawa (FWO) methods, were applied. The ASTM-E698 approach yielded an apparent activation energy (Ea) of 172.09 kj.mor1, whereas the FWO method yielded an Ea range from 38 to 172 kj.mor1. Finally, the differential iso-conversional approach yielded Ea values ranging between 85 and 191 kj.mor1. Kinetic predictions were then developed for isothermal, non-isothermal, and stepwise configurations using the kinetic parameters obtained via Friedman's model. The forecasts shed light on optimising production throughput in a variety of reactor configurations. [ABSTRACT FROM AUTHOR]

The utilization of agricultural solid biowastes is essential for resource saving and bioenergy conversion. By this way, the demand of industrial furnace for biomass would be compensated, and the energy structure would also be greener. Among them, torrefaction is a hopeful technology for solid biofuel production. This study investigates the grinding performance of torrefied biochar to achieve the grindability and component variation analysis of torrefied agricultural wastes for fluidized bed boiler, and thus realize pulverized biochar injection for industrial application. Totally crystallinity index (CrI), average particle size distribution, energy input for grinding process, component analysis, and elemental carbon state are adopted and analyzed around Hardgrove grindability index (HGI). The values of HGI are in the range of 45–120, 45–105, 60–120, and 60–135, respectively. The results indicate that torrefaction is conducive for biochar properties upgrading, especially for a higher temperature, and thus contributes to a higher HGI, lower particle size and grinding energy input, as well as better elemental carbon state. The produced powder from torrefied biochar is highly correlated to torrefaction temperature and biochar component, and thus leads to an excellent industrial application potential. Overall, this study is conducive for the agricultural biowastes conversion and solid biofuel production. [Display omitted] • The grindability of four agricultural solid biowastes were analyzed. • Torrefaction is conducive to achieving biochar grindability improvement. • Grindability is correlated to crystallinity index and grinding energy input. • A higher torrefaction temperature is conducive for biochar powder size reduction. • Biochar component and carbon state are correlated to grindability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar and agri-waste fight pollution effectively, being eco-friendly. • Study evaluates factors impacting wastewater treatment insights. • Agri-waste is key in pyrolysis, removing pollutants efficiently and cheaply. • NM shows 0-95% efficiency, tackling varied wastewater issues. There is a growing emphasis on harnessing the potential of agricultural waste, biochar, and nanomaterial (NM). This review explores their utilization, highlighting their role in mitigating environmental contamination. Methodology encompasses a comprehensive comparative analysis focusing on patterns discerned within key parameters such as pollutant types, temperature, specific surface, contact times, and pH levels in the study of wastewater treatment. This analysis employs advanced visualization tools like radar, contour, and Q-Q plots to unravel insights into heavy metals and other elements' removal efficiency. This study reveals the effectiveness of agricultural waste, particularly in pyrolysis processes, for removing various pollutants like sulfamethoxazole, phenol, and acid orange 7 along with microstructural analysis. The pH range of 5–8 demonstrates its significance in these removal processes. Furthermore, nanomaterials (NM) exhibit a wide spectrum of removal efficiencies of heavy metal ions and other pollutants, ranging from 0 % to 95 %, over extended treatment durations of up to 2500 min, underlining their potential in diverse wastewater treatment scenarios. The utilization of agricultural waste, biochar, and nanomaterials for environmental remediation strongly corresponds with key UN Sustainable Development Goals, spanning clean water, responsible consumption, climate action, biodiversity preservation, and innovation, showcasing a holistic strategy for sustainable development. [ABSTRACT FROM AUTHOR]

[Display omitted] • A waste-to-treasure approach was first used to build biochar nanozymes arrays. • Colorimetric sensor arrays distinguished 5 pesticides rapidly and accurately. • Pesticides were detected and discriminated in soil, water, and food. Despite the potential of nanozymes combined with sensor arrays for discriminating multiple pesticides simultaneously, they have few practical pesticide sensing uses due to the limited performance of existing nanozymes and the complexity of their preparation. Here, agricultural waste is utilized for the facile synthesis of high-performance biochar nanozymes and the fabrication of biochar nanozyme sensor arrays. The production of autogenous N-doped biochars with abundant surface functional groups and good peroxidase-like activities is achieved with different types of algae. High-performance biochar nanozyme sensor arrays can discriminate pesticides in a concentration range from 1 to 500 μM and in real samples from soil, lake water, seawater, apples, cucumbers, peaches, tomatoes and cabbages. Furthermore, pesticides can be quantified down to 1 μM. The development of high-performance nanozyme sensor arrays based on waste conversion could be a step toward pesticide discrimination and detection, which would improve human and environmental safety. [ABSTRACT FROM AUTHOR]

[Display omitted] • The biochar of soybean (SB), adzuki beans (AB), and mung beans (MB) were prepared. • AB exhibited superior surface-area-normalized catalytic ozonation activity. • AB contained highest pyridine N and pyrrole N which enhanced ozone activation. • OH, O 2 − and 1O 2 were the main produced ROS for 2,6-dimethylpyrazine degradation. Designing efficient and environmentally friendly catalysts is essential to activating ozonation for wastewater remediation. This study prepared soybean biochar (SB), adzuki beans biochar (AB), and mung beans biochar (MB) catalysts using moldy legumes as precursors. The biochars were characterized to investigate the surface characters' effect on ozone activation toward 2, 6-dimethylpyrazine (2,6-DMP) degradation. All prepared samples drastically facilitated the degradation more than with sole ozonation. It was found that at pH 7 with 10 mg L−1 catalysts, the removal rates of 5 μM 2,6-DMP were 88.3 %, 90.7 %, and 87.3 % by SB, MB, and AB at 30 min, respectively. The surface-area-normalized reaction rate constants (k obs /S BET) showed that AB exhibited the best catalytic activity with the rate of 1.5 × 10−2 mg·m2·min−1, which is 2.3- and 23.1-fold higher than that of SB and MB, respectively. Further characterization confirmed that oxygen- (C–O/C = O and –OH) and nitrogen-containing groups (pyridine N and pyrrole N) were crucial to the catalytic degradation, as electron transfer was promoted to form more ROS. In addition, the quenching test and electron paramagnetic resonance (EPR) revealed OH, O 2 −, and 1O 2 as the main reactive oxygen species (ROS) during the heterogeneous catalytic ozonation (HCO), indicating that 2,6-DMP degradation followed the radical and non-radical oxidation pathways. Overall, this study helped to understand the relationship between surface functional groups and intrinsic activity. It also provided a new direction for utilizing agricultural waste. [ABSTRACT FROM AUTHOR]

Agricultural residues in excess of livestock fodder are garnering global attention and stern concerns owing to their accountable share in environmental hazards due to the lack of effective disposal mechanisms and indiscriminate burning. Recycling these residues for biochar production using pyrolysis is a cost-effective and locally feasible technique which offers a twin-prong solution addressing both climate and soil health issues. This research work compares a portable kiln prototype that is affordable and easy to use, with a muffle furnace at three distinct pyrolytic temperatures (400 °C, 500 °C, and 600 °C) to produce biochar from the stalks of maize and pigeonpea. The biochar properties were characterized using Electron Microscopy-Electron Dispersive X-ray (SEM-EDX), X-ray Diffraction (XRD), Fourier Transmission Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA). The findings indicate significant variations in biochar properties based on raw material source, pyrolytic method, and varied temperatures. Higher pyrolysis temperatures were found to reduce the amorphous organic phase and alter the ultrastructure of biochar, as evidenced by XRD analysis. SEM imaging showed macropores in oval and round shapes with crystalline deposits. The carbon content, as per EDX, decreased with increasing temperature, aligning with changes in functional groups. Edinburgh's stability test revealed that kiln biochar has more stable carbon content compared to biochar produced using muffle furnace and the stable carbon increased with the rise in temperature. A comparative analysis demonstrated that biochar quality at 400–500 °C in a muffle furnace was on par with that produced in the portable kiln at 400 °C. Therefore, considering the kiln's portability, efficiency, cost-effectiveness, and scalability, it is a promising decentralized method for biochar production, offering a cutting-edge solution for agricultural waste management and soil carbon enhancement. [Display omitted] • The study involves redesigning and development of low-cost portable kiln for economical and decentralized biochar production using pigeonpea and maize stalks. • Physiochemical characterization of kiln biochar produced at 400 °C is comparable to muffle furnace biochar produced at 400 °C and 500 °C. • The stable carbon content is more in biochar produced using kiln compared to muffle furnace. • The heavy metal content in the biochar produced is less than critical limits (International biochar initiative). • The low capital and operational cost of kiln proves the technology economical and scalable. [ABSTRACT FROM AUTHOR]

• A porous foam-like biochar was prepared. • The hydrophobicity and photothermal conversion capability were explored. • This biochar possesses excellent adsorption capability for hazardous chemicals. • Photothermal conversion capability promotes its adsorption for viscous oil. Biochar is considered as a promising adsorbent due to its unique porous structure, large surface area and lightweight nature. In this study, pomelo peel was used as raw material, and graphene oxide was introduced as a functional material. High-temperature carbonization was employed to achieve simultaneous carbonization of pomelo peel and thermal reduction of graphene oxide, resulting in the preparation of a porous sponge-like biochar with high hydrophobicity, thermal stability and photothermal conversion capability. This biochar was successfully applied to the efficient separation of various oil–water mixtures, demonstrating excellent cyclic adsorption stability. Furthermore, by harnessing its photothermal conversion effect, efficient absorption of viscous oil product was achieved. This study proposes a facile biochar preparation strategy that can expand its application in the field of oil spill emergency treatment and promote the utilization of agricultural waste. [ABSTRACT FROM AUTHOR]

The study highlights the potential of Bacillus spp. SSAU-2 in rejuvenating soil fertility and emphasizes the importance of microbe adsorption on activated biochar. The primary objective is to restructure the quality of Cr (VI)-contaminated soil through the strategic use of bacteria and cyanobacteria immobilized on biochar derived from rice straw. The synthesized activated charcoal is highly porous, and immobilization significantly boosts the bacteria's ability to remove Cr (VI) from the soil. This ability increased from a threshold value of 60 ppm Cr (VI) to 500 ppm Cr (VI), indicating its efficacy. The microbe demonstrated multi-heavy metal tolerance, surviving even in 1000 ppm heavy metal concentrations. Moreover, the study revealed increased phosphate solubilization (49%), conductivity (175%), and salinity (53%), demonstrating the microbe's efficiency in solubilizing metal salts in the soil. The study also focuses on the community behavior of the bacterium in the soil in which it was found that the SSAU-2 mingles quite efficiently with the soil. Scanning Electron Microscope images confirmed the effective colonization of microbes within the pores of activated charcoal. Thus study presents a novel approach for the effective remediation of Cr (VI)-contaminated soil through the application of Bacillus sp. SSAU-2 immobilized on biochar. The research explored the dual benefits of heavy metal removal and repurposing of agricultural waste through open burning. [Display omitted] • This study addresses various facets of soil improvement through a symbiotic association. • SSAU-2 exhibits resistance to a spectrum of heavy metals, including Cu, Zn, Hg, Cr, Fe, Mn, and Pb. • The varying levels of resistance indicate the adaptability of SSAU-2 to diverse soil conditions. • SSAU-2's immobilization on biochar significantly amplifies its capacity for Cr (VI) removal. [ABSTRACT FROM AUTHOR]

Stover and manure are the main solid waste in agricultural industry. The generation of stover and manure could lead to serious environmental pollution if not handled properly. Composting is the potential greener solution to remediate and reduce agricultural solid waste, through which stover and manure could be remediated and converted into organic fertilizer, but the long composting period and low efficiency of humic substance production are the key constraints in such remediation approach. In this study, we explore the effect of lignocellulose selective removal on composting by performing chemical pretreatment on agricultural waste followed by utilization of biochar to assist in the remediation by co-composting treatment and reveal the impacts of different lignocellulose component on organic fertilizer production. Aiming to discover the key factors that influence humification during composting process and improve the composting quality as well as comprehensive utilization of agricultural solid waste. The results demonstrated that the removal of selective lignin or hemicellulose led to the shift of abundances lignocellulose-degrading bacteria, which in turn accelerated the degradation of lignocellulose by almost 51.2%. The process also facilitated the remediation of organic waste via humification and increased the humic acid level and HA/FA ratio in just 22 days. The richness of media relies on their lignocellulose content, which is negatively correlated with total nitrogen content, humic acid (HA) content, germination index (GI), and pH, but positively correlated with fulvic acid (FA) and total organic carbon (TOC). The work provides a potential cost effective and efficient framework for agricultural solid waste remediation and reduction. [Display omitted] • Lignocellulose removal provides humus precursors and speeds up composting. • Removal of lignin increase abundance of the lignocellulose-degrading bacteria. • Removal of hemicellulose enhances the abundance of cellulose-degrading bacteria. • Fulvic acid is the key driven the succession of bacterial community in composting. [ABSTRACT FROM AUTHOR]

Cotton stalk (CS) is a global agricultural residue, with an annual production of approximately 50 million tons, albeit with limited economic significance. The utilization of cellulose derived from CS has gained significant attention in green nanomaterial technologies. This interest stems from its unique properties, including biocompatibility, low density, minimal thermal expansion, eco-friendliness, renewability, and its potential as an alternative source for chemicals, petroleum, and biofuels. In this review, we delve into various extraction and characterization methods, the physicochemical attributes, recent advancements, and the applications of cellulose extracted from CS. Notably, the steam explosion method has proven to yield the highest cellulose content (82 %) from CS. Moreover, diverse physicochemical properties of cellulose can be obtained through different extraction techniques. Sulfuric acid hydrolysis, for instance, yields nanocrystalline cellulose fibers measuring 10–100 nm in width and 100–850 nm in length. Conversely, the steam explosion method yields cellulose fibers with dimensions of 10.7 μm in width and 1.2 mm in length. CS-derived products, including biochar, aerogel, dye adsorbents, and reinforcement fillers, find applications in various industries, such as environmental remediation and biodegradable packaging. This is primarily due to their ready availability, cost-effectiveness, and sustainable nature. [ABSTRACT FROM AUTHOR]

• Biochar may facilitate a circular bioeconomy for agricultural waste. • Stochastic cost modeling is used to evaluate uncertainty in cost estimations. • Production costs ∼$448.78–$1,846.96 (USD) Mg−1 biochar. • A biochar enterprise budget is provided as supplemental material. • Indirect and induced regional economic benefits are shown. It is well established that the global practice of burning crop residues, such as orchard biomass, harms human health and the environment. A bioeconomy for orchard biomass may reduce open burning, facilitate the recovery of nutrients that improve soil health, and boost economic growth. We present a techno-economic analysis for converting orchard waste into biochar, a charcoal-like substance that shows promise for improving soil health, but that is considered an experimental product with emerging efficacy and limited market demand. We impute values derived from a cost analysis of biochar production in California's Central Valley into a regional economic input-output model to demonstrate economic growth and a bioeconomy for biochar made with orchard waste. Results from a stochastic Monte Carlo simulation show a probable range of biochar production costs between $448.78 and $1,846.96 (USD) Mg−1, with 90% probability that costs will range between $571 and $1,455 Mg−1. A sensitivity analysis shows that production costs are most responsive to biochar production rates. A modifiable Excel-based biochar enterprise budget that includes fixed and variable biochar production costs is provided as Supplementary Material. The regional economic analysis demonstrates positive economic growth as defined by job creation, labor compensation, value-added product, and gross output. Stochastic cost estimates and net positive regional economic impacts support economic feasibility of a circular bioeconomy for waste orchard biomass when coupled with governmental policy initiatives. Results may contribute to developing a circular bioeconomy for biochar and orchard biomass in the study region and elsewhere in the world. [ABSTRACT FROM AUTHOR]

• Co-pyrolysis of manure and different biomass wastes were investigated at 600 °C. • Specific biomass addition resulted in targeted improvement in biochar characteristics. • Co-pyrolysis decreased the concentrations and bioavailability of Cu and Zn in biochar. • Environmental risk assessment verified the biochar safety for additional application. Biomass waste is a desirable additive in livestock feces biochar preparation due to its easy access, better moisture adjustment, and abundant organic content. In the present study, co-pyrolysis of livestock feces (PM: pig manure, CM: chicken manure) and biomass wastes (WC: wood chips, BS: bamboo sawdust, RH: rice husk, and CH: chaff) with different blending ratios was conducted at 600 °C to investigate the biochar characteristic and Cu/Zn immobilization performances. The results showed that WC and BS have more significant effect on the increase in fixed carbon content and heating value and the decrease in ash content of biochar. The biochar with lower pH and electrical conductivity is obtained from co-pyrolysis of manure with RH and CH. Compared with CM-based biochar, PM-based biochar presented better potential as fuel and soil remediation considering the higher heating value and lower aromatic H/C ratio. Specially, the residual fractions of Cu and Zn in PM biochar increased from 73.09% and 65.54% to 90.68% and 72.31% after 10 wt% BS addition and those in CM biochar increased from 81.07% and 73.57% to 88.87% and 84.11% after 10 wt% WC addition, which induced the lowest environmental risk of biochar. This work provided a strategy and direction for targeted enhancement in biochar characteristics with selective biomass addition during manure pyrolysis, which is beneficial to the local treatment and utilization of farm wastes. [ABSTRACT FROM AUTHOR]

Various silicon carbide nanostructures are attracting close attention due to their excellent performance and great potential, including utilization in a variety of catalytic applications. Approaches, utilizing different industrial wastes as a starting material for the synthesis of SiC nanoparticles, are especially distinguished due to their environmental friendliness. This paper demonstrates a new two-stage technique of the preparation of dispersed SiC/C nanocomposite. A highly mineralized carbonaceous residue obtained by thermal processing of agricultural waste was used as a precursor for the synthesis in a pulsed arc discharge plasma. Rice husks, oat husks and oat straw were chosen as agricultural wastes with a high content of silicon in the mineral component. Carbonaceous residues (biochars) were obtained from the selected wastes by oxidative carbonization in a reactor with a fluidized bed of a deep oxidation catalyst at 460 °C. High-energy (up to 20 kJ) treatment of the obtained biochars in a pulsed (up to 1 ms) arc discharge plasma jet resulted in synthesizing a nanodispersed material (particle size <50 nm) containing hexagonal silicon carbide α-SiC. The principal possibility of using the synthesized SiC-based composite as a catalyst and cocatalyst of platinum in the hydrogen evolution reaction (HER) of water splitting is shown. The most impressive results (η 10 = 18–28 mV, η 100 = 84–98 mV, b = 32–64 mV) comparable with standard commercial Pt/C samples were obtained by modifying the synthesized SiC-based composite with 5 % platinum. Thus, the developed approach allows us to convert the agricultural waste into useful high-tech products in the form of an electrocatalytically active material. [Display omitted] • A new two-stage approach provides SiC/C nanocomposite from Si-containing biomass. • The proposed approach is almost CO 2 -neutral when utilizing plant agricultural waste. • Pt-modified SiC/C composites has a high activity in HER reaction of water splitting. • Catalytic performance and stability of Pt/SiC/C is almost equal to commercial Pt/C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wet and dry wastes mixed in cascading thermochemical valorization pathways. • Hydrothermal carbonization (HTC) as pyrolysis pretreatment enhances biochar HHV. • HTC as pretreatment decreases biochar volatile matter beyond additive prediction. • Mixing dry waste with hydrochar lowers acidity and O/C of pyrolysis bio-oil. Two thermochemical valorization schemes were investigated for co-upgrading dry and wet agricultural wastes through integrated hydrothermal carbonization (HTC) and pyrolysis. In the first pathway, dry and wet wastes were co-carbonized. The resulting hydrochar was pyrolyzed to yield an energy dense biochar (26–32 MJ/kg) high in fixed carbon (41–86 wt%) and low in volatile matter (6–12 wt%). The resulting bio-oil was lower in carboxylic acids and higher in phenols than predicted based on an additive scheme. In pathway two, wet waste (only) underwent HTC and the resulting hydrochar was mixed with dry waste and the mixture pyrolyzed. This pathway showed a lower biochar yield (32–67 wt%) and lower HHV values (24–31 MJ/kg) but higher fixed carbon content (65–84 wt%). The bio-oil contained more carboxylic acids than pathway 1 bio-oil. Pathway 1 biochars were more thermally reactive than pathway 2 biochars, reflecting a synergistic deoxygenation that occurs when incorporating dry waste in HTC prior to pyrolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pig manure and straw co-pyrolysis biochar (CPB) shows promising functional traits. • CPB effectively curtails NPS pollutants in paddy runoff, cutting nutrient loss. • CPB enhances soil nutrient retention and a significant increase in crop yield. • CPB stimulates microbial growth and reproduction, promoting nutrient cycling. • CPB as a nutrient reservoir (store and release), enhancing utilization efficiency. The current study generated co-pyrolysis biochar by pyrolyzing rice straw and pig manure at 300 °C and subsequently applying it in a field. Co-pyrolysis biochar demonstrated superior efficiency in mitigating agricultural non-point source pollution compared to biochar derived from individual sources. Furthermore, it displayed notable capabilities in retaining and releasing nutrients, resulting in increased soil levels of total nitrogen, total phosphorus, and organic matter during the maturation stage of rice. Moreover, co-pyrolysis biochar influences soil microbial communities, potentially impacting nutrient cycling. During the rice maturation stage, the soil treated with co-pyrolysis biochar exhibited significant increases in available nutrients and rice yield compared to the control (p < 0.05). These findings emphasize the potential of co-pyrolysis biochar for in-situ nutrient retention and enhanced soil nutrient utilization. To summarize, the co-pyrolysis of agricultural waste materials presents a promising approach to waste management, contributing to controlling non-point source pollution, improving soil fertility, and promoting crop production. [ABSTRACT FROM AUTHOR]

Biochar can be used to improve the anaerobic digestion (AD) of agricultural wastes for higher methane production. However, the interaction of biochar addition with other factors of the anaerobic co-digestion (Co-AD) process has rarely been investigated. In this study, process models based on response surface methodology (RSM) and artificial neural network (ANN) were compared in modeling the methane yield (MY, mL CH 4 /g VS added) from the Co-AD of poultry litter and wheat straw with biochar addition. Box-Behnken design was applied, with the controlling parameters being carbon to nitrogen ratio (C/N), total solids (TS, %), and biochar addition (Biochar, % TS). Numerical optimization and genetic algorithm (GA) were used as optimization tools for RSM and ANN, respectively. A significant second-order quadratic model was built by RSM (R2 = 0.9981 and RMSE = 0.91), which demonstrated significant interactions between C/N and TS (p < 0.0001), and between C/N and Biochar (p < 0.05). The trained ANN (3−3−1) was less accurate (R2 = 0.9926, RMSE = 1.80) compared to RSM. The optimization results by RSM and ANN coupled with GA (ANN-GA) were both validated with prediction errors <0.5%. The optimization results by ANN-GA should be used since it generated a higher maximum MY of 290.7 ± 0.2 mL CH 4 /g VS added , under the optimal conditions of C/N ratio 24.46, TS 5.03%, and Biochar 8.73% TS, showing an improvement of 20.6% (compared to the control) through process optimization. The methods can also be applied in other scenarios for process modeling and optimization. The optimized results could support real applications of using additives including biochar, active carbon, nanoparticles, etc., to promote the bioenergy production from AD of agricultural wastes. [Display omitted] • Poultry litter and wheat straw were co-digested for bioenergy (methane) production. • Biochar-improved anaerobic co-digestion was modeled based on a Box-Behnken design. • Response surface methodology and artificial neural network (ANN) were compared. • RSM indicated a significant interaction between biochar addition and substrate carbon-to‑nitrogen ratio. • Optimal methane yield was determined by ANN coupled with genetic algorithm. [ABSTRACT FROM AUTHOR]

The use of agricultural byproducts as feedstocks for the synthesis of biochar might result in the release of total petroleum hydrocarbons (TPHs) because of the presence of various plastic residues, such as plastic film mulch, gloves, and poles. TPH has been considered a critical health concern for humans worldwide. The aim of the present study was to evaluate the effect of different pyrolysis temperatures and durations on reducing the TPH concentration while synthesizing biochar using agricultural byproducts as feedstock materials. Agricultural byproducts, comprising sawdust and plastic films, were pyrolyzed as feedstocks at temperatures of 400, 500, 600, and 700 °C for durations of 0.5, 1, 2 and 3 h, respectively. Pyrolyzing the feedstock at 500 °C for 1 h and at 600 °C for 0.5 h significantly reduced the TPH concentration in the biochar by 98 and 91 %, respectively, compared to that at 400 °C for 0.5 h. The highest biochar yield was obtained at the lowest pyrolysis temperature (400 °C) and the shortest pyrolysis duration (0.5 h), with a subsequent steady decrease as the temperature and duration increased. These findings underscore the importance of understanding pyrolysis conditions for producing low-cost but high-quality biochar with reduced TPH contaminants and increased biochar yield. This research offers valuable insights for developing sustainable strategies for minimizing the health risks of TPH and utilizing biochar for environmental benefits. [Display omitted] [ABSTRACT FROM AUTHOR]

Is biochar obtained from agricultural residues an alternative to the coal used in blast furnaces - BF ? This work provided a comparison between biomass and PCI coal, and evaluated the influence of pyrolysis temperature on the combustion indexes and physicochemical properties of biochars. Coconut-shell, corncob, and eucalyptus bark biomasses were pyrolyzed at different temperatures (300 °C–500 °C) to produce biochar. Samples of biomasses and biochars were characterized using proximate analysis, HHV, FTIR, XRD and SEM coupled with EDXA. Pyrolysis led to increased fixed carbon content and HHV in the biochar. However, the higher the temperature, the lower the mass yield. The combustion indexes results revealed that the raw biomasses do not meet the reference values. Coconut-shell and corncob biochars produced at 300 °C and 350 °C demonstrated combustion indexes similar to those of reference PCI coal. The results suggested that both the choice of biomass and the pyrolysis temperature had influence on the properties of biochar produced. Coconut-shell and corncob biochars, produced at relatively low temperatures, exhibited suitable combustion properties and could serve as partial substitutes of PCI coal in a BF. Eucalyptus bark biochar, due to its higher ash content, may be less suitable for these applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Agricultural waste conversion is of great concern to achieve modernization and industrial development and thus leads to a greener route for a sustainable and circular economy. The treatment of corn stalk for pellet production to realize industrial application is implemented, which is conducive to upgrading fuel properties with better storage and transportation characteristics. The obtained results indicate that torrefaction operation is helpful for pellet density enhancement, with a value of up to larger than 0.74 g cm−3. However, the wear strength and hardness are not good enough compared to raw corn stalk, with values of 4.5–7.5 % and 88 kN–92 kN, respectively. A longer compression duration contributes to a greater work condition and higher relative HHV, which is conducive to energy efficiency improvement. To further evaluate the hygroscopicity and moisture resistance capacity of pelletized corn stalk for fuel properties evaluation, the equilibrium moisture content and contact angle reflect that the enhancement of pressure and compression duration are beneficial for moisture resistance capacity improvement, with the values of less than 3.5 % and higher than 130°. When considering the fuel properties and pelletization cost, compromising on operation conditions should be adopted for optimal operation. [Display omitted] • The pelletization for agricultural waste valorization is investigated. • Torrefaction temperature substantially impacts pellet fuel properties. • Pressure and compression duration are dominant in enhancing pellet stability. • Pelletization is conducive to improving biomass moisture resistance capacity. • The environmental and economic feasibility of the pellet is implemented. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diverse biochar adsorbents were produced from Goji branch by co-pyrolysis with KOH. • Appropriate moisture in agro-wastes contributed to develop porosity in biochar. • K 50% W 29% C-700 presented S BET of 1378.05 m2/g and Q m of 769.23 mg MB/g. • K 50% W 29% C-700 showed excellent reusability and wide applicability. The agricultural waste (Goji branch) was pyrolyzed into biochars with one-step potassium hydroxide (KOH) activation under different processing conditions. The biochars were first characterized in structural features and functional groups and then evaluated for adsorptive performance with methylene blue as a model pollutant. Different adsorption models were applied to fit the adsorption process and reveal the possible mechanisms. The adsorption capacity was found to strongly correlate (R2 = 0.9642) with the surface area of the biochars, among which biochar K 50% W 29% C-700 (pyrolysis at 700 °C in the presence of 50 % KOH and 29 % water) possessed the largest surface area (1378 m2/g) and exhibited the highest adsorption capacity (769 mg/g) compared to its homologous products. Biochar K 50% W 29% C-700 also showed excellent recyclability and potent adsorption capacity toward other common organic pollutants. The results suggest that traces of water in agricultural wastes could significantly intensify the KOH-involved activation efficiency of producing porous biochar. [ABSTRACT FROM AUTHOR]

Straw biochar loaded zero-valent iron nanoparticles were prepared by co-precipitation method using agricultural waste straw biochar as a carrier for the removal of p-nitrophenol (PNP) by activated sodium persulfate (PS). The physicochemical properties of BC@nZVI were characterized using SEM, EDS, FTIR, BET, and RAMAN. The effects of PS concentration, catalyst concentration, initial pH, coexisting anions, and different activation systems on the degradation of PNP were investigated. The results showed that the best activation effect was exhibited at pH= 7, BC@nZVI dosage of 2 g/L, and PS concentration of 1 mM, and the removal of 40 mg/L PNP reached 91.7 % in 10 min. The high concentration of PS (4 mM) triggered free radical competition to inhibit the degradation, and the removal rate was only 74.5 % at 1 mM. In addition, bicarbonate ions (0–20 M) had a significant inhibitory effect on this system. Electron spin resonance (ESR) demonstrated that SO 4 ⋅ − and·OH were the major radicals, and SO 4 ⋅ − was preferentially generated. The intermediate products were identified by LC-MS, XRD and XPS characterization, which showed that adsorption and redox were the main degradation mechanisms, with p-benzoquinone was the oxidized product and substances such as 4-heptanone and propionic acid were the reduced products. This study proves that BC@nZVI activated PS is an efficient and excellent means of removing PNP and a good way to reuse agricultural waste. [Display omitted] • Higher PNP deposition capacity and efficiency were obtained in the BC@nZVI-PS system. • Examining the effects of PS concentration, degradation system, anion influence and other factors. • Free radical quenching and ESR reveal the main radicals in the degradation process. • Propose and describe the degradation pathway of BC@nZVI activated PS for PNP removal. [ABSTRACT FROM AUTHOR]

Biochar has been explored as a sorbent for contaminants, soil amendment and climate change mitigation tool through carbon sequestration. Through the optimization of the pyrolysis process, biochar can be designed with qualities to suit the intended uses. Biochar samples were prepared from four particle sizes (100–2000 µm) of three different feedstocks (oak acorn shells, jift and deseeded carob pods) at different pyrolysis temperatures (300–600 °C). The effect of these combinations on the properties of the produced biochar was studied. Biochar yield decreased with increasing pyrolysis temperature for all particle sizes of the three feedstocks. Ash content, fixed carbon, thermal stability, pH, electrical conductivity (EC), specific surface area (SSA) of biochar increased with increasing pyrolysis temperature. Volatile matter and pH value at the point of zero charge (pH pzc) of biochar decreased with increasing pyrolysis temperature. Fourier-transform infrared spectroscopy (FTIR) analysis indicated that the surface of the biochar was rich with hydroxyl, phenolic, carbonyl and aliphatic groups. Methylene blue (MB) adsorption capacity was used as an indicator of the quality of the biochar. Artificial neural networks (ANN) model was developed to predict the quality of the biochar based on operational conditions of biochar production (parent biomass type, particle size, pyrolysis temperature). The model successfully predicted the MB adsorption capacity of the biochar. The model is a very useful tool to predict the performance of biochar for water treatment purposes or assessing the general quality of a design biochar for specific application. [ABSTRACT FROM AUTHOR]

• Biochars from agricultural residue facilitate nutrient cycle in sustainable agriculture. • Feedstock, temperature, and residence time altogether determined biochars properties. • Straw biochars contained a high level of K but limited amounts of N and P. • Biochars have limited ability in retaining soluble PO 4 3− and NO 3 −. In this study, the influence of production conditions (i.e., pyrolysis temperature and residence time) on the fundamental properties and the nutritional traits of biochars derived from different feedstocks (corn stalk, rape straw, wheat stalk, and peanut shell) were investigated. The results showed that pyrolysis temperature was a critical parameter affecting biochar properties, whereas the influences of residence time and feedstock were comparatively weaker. Biochar properties, including the pH, ash content, electrical conductivity (EC), oxidation stability, and the ability to retain nutrients, were positively related with increasing temperature and prolonged residence time. However, the water-extractable organic matter and available nutrients were negatively related with temperature and residence time. There was a minimal release of NH 4 +-N, NO 3 −-N, and PO 4 3−-P from the generated biochars, and their concentrations were reduced through carbonization. By comparison, the water-soluble K+ content steadily increased with pyrolysis. Generally, the biochars showed a limited capacity for sorbing PO 4 3− and NO 3 −, although the removal efficiencies were enhanced by pyrolysis. By comparison, higher NH 4 + removal was achieved by biochars, and particularly for biochars with a higher pH. These findings suggest that the application of agricultural residue-derived biochars might not provide plants with sufficient nutrients (except for K). Additionally, the biochars generated at 500 °C for a duration of 1 h demonstrated higher potential for carbon sequestration. [ABSTRACT FROM AUTHOR]

The thermochemical conversion of four types of biomass in a batch-fed reverse downdraft process for heat generation in cookstoves is investigated. Fuel switching is widely considered inefficient because many combustion devices do not respond well to changes in fuel. Here, the use of agricultural by-products, represented by wheat straw, sheep manure, cow manure, and wood pellets is addressed. Two air supply rates within the oxygen-limited regime, where the fuel consumption is linearly dependent on the air supply, are investigated. At higher air supply rates, in the reaction-limited regime, low carbon yields lead to the exposure of the ash fraction to high temperatures, such that the resultant ash melting has detrimental effects on the process. Generally, no detrimental impact of the ash content on the conversion process within the oxygen-limited regime could be identified. The release of gaseous products, evaluated through cold gas efficiency, increases linearly from 24 to 54% with higher air flow, corresponding to increasing process temperatures from 690 to 980 °C, and is largely fuel type independent. The char produced from all feedstocks fall within the highest classification for biochars, based on its elemental composition and determined by international protocols. This emphasises the potential of the investigated process for a combined production of producer gas and biochar from a variety of low-value biomass feedstocks. • Thermochemical conversion of wood, wheat straw and sheep and cow manure was performed. • Fuel consumption in reverse downdraft process exhibits dependence on the ash content. • The cold gas effciency scales linearly from 24 to 54% with the process temperature. • Produced biochars are of high quality for soil amendment purposes. • Limited the air supply enables effcient production of producer gas and biochar. [ABSTRACT FROM AUTHOR]

Domestic energy sources in sub-Saharan Africa are still mainly comprised of firewood and charcoal. One of the main challenges affecting the uptake of carbonized briquettes is their inefficiency in transferring heat. In this study bio-composite briquettes were developed from rice husks, coffee husks and groundnut shells, in varying proportions. The briquettes were developed under low pressure (≤7 MPa) after carbonization and application of starch binder. Thermal properties of the developed bio-composite briquettes were determined by using a bomb calorimeter and thermogravimetric analysis to determine calorific values and physical properties, respectively. Drop strength tests and particle density determinations were performed to study the mechanical strength and integrity of the developed briquettes. The water-boiling test was used to determine time taken to boil 1 L of water. Fourier's Law of heat conduction was used to investigate heat transfer rates across the briquettes for conditions of binder/binder-less bonding conditions. Calorific values for the developed briquettes ranged between 16.6 MJ/kg and 22 MJ/kg. Results for drop strength for the developed composite briquettes were all above 86%, indicating satisfactory characteristics. Bio-composite briquettes developed using coffee and rice husks bio-chars took less time to boil water compared to all the other bio-composite briquette combinations. Particle densities ranged between 430 kg/m3 and 580 kg/m3. Heat transfer was enhanced when no binder was present and coffee and rice husks were sequentially placed in the briquette composition. This study showed the advantages of producing bio-char bio-composite briquettes over single constituent briquettes. Bio-composite carbonized briquettes produced from rice husks, coffee husks and groundnut shells are a suitable and sustainable alternative to firewood and charcoal use in sub-Saharan Africa. • Bio-char bio-composite briquettes were developed from agricultural residues. • Calorific values for the developed briquettes ranged between 16.6 MJ/kg and 22 MJ/kg. • Drop strength for the bio-composite briquettes were all above 86%. • Particle densities ranged between 430 kg/m3 and 580 kg/m3. • Heat transfer was enhanced when no binder was present. [ABSTRACT FROM AUTHOR]

Rice husk is a common agricultural waste. The utilization of rice husk biochar depends on the characteristics of biochar and its interaction mechanisms with heavy metals. In the present study, rice husk biochars at three different temperatures 300, 500, and 700 °C were produced (RH300, RH500, and RH700). The characteristics of these rice husk biochars and their interaction mechanisms with lead (Pb) were investigated, in order to reveal the potential environmental applications of the biochars. It was observed that the surface area (from 0.632 to 193.149 m2/g) and pH (from 7.13 to 9.80) of the rice husk biochars significantly increased as production temperature rose from 300 to 700 °C, while the number of functional groups (e.g., carboxyl) decreased. The Langmuir maximum removal capacity (Q max) values for Pb are in the order of RH300 < RH500 < RH700 (14.1, 21.7, and 26.7 mg/g respectively). Although RH300 has the smallest Q max value, its exchangeable Pb amount is the largest (2.61 versus 0.223–0.377 mg/g), suggesting RH300 may be suitable for water treatment due to the easy separation of immobilized Pb and better recycling usage. The Pb immobilized on RH500 and RH700 was mainly acidic soluble and generally stable. Hydrocerussite is one important form within the acidic soluble fraction. Within the generally stable formation, pyromorphite is a form for the immobilized Pb on the rice husk biochars, particularly for RH500 and RH700. These findings suggest RH500 and RH700 are of promising potential to be applied in soil remediation to immobilize Pb and reduce its environmental risks. • The adsorption capacity for lead is in the order of RH300 < RH500 < RH700. • The exchangeable Pb amount on biochar is in the order of RH300 > RH500 > RH700. • Hydrocerussite and pyromorphite formed on biochars particularly for RH500 and RH700. • Rice husk biochar produced at 300 °C is suitable for water treatment. • Rice husk biochars produced at 500 °C and 700 °C are suitable for soil remediation. [ABSTRACT FROM AUTHOR]

Proper management of waste crop residues has been an environmental concern for years. Yellow mealworms (larvae of Tenebrio molitor Linnaeus, 1758) are major insect protein source. In comparison with normal feed wheat bran (WB), we tested five common lignocellulose-rich crop residues as feedstock to rear mealworms, including wheat straw (WS), rice straw (RS), rice bran (RB), rice husk (RH), and corn straw (CS). We then used egested frass for the production of biochar in order to achieve clean production. Except for WS and RH, the crop residues supported mealworms' life activity and growth with consumption of the residues by 90% or higher and degraded lignin, hemicellulose and cellulose over 32 day period. The sequence of degradability of the feedstocks is RS > RB > CS > WS > RH. Egested frass was converted to biochar which was tested for metal removal including Pb(II), Cd(II), Cu(II), Zn(II), and Cr(VI). Biochar via pyrolysis at 600 °C from RS fed frass (FRSBC) showed the best adsorption performance. The adsorption isotherm fits the Langmuir model, and kinetic analysis fits the Pseudo-Second Order Reaction. The heavy metal adsorption process was well-described using the Intra-Particle Diffusion model. Complexation, cation exchange, precipitation, reduction, deposition, and chelation dominated the adsorption of the metals onto FRSBC. The results indicated that crop residues (WS, RS, RB, and CS) can be utilized as supplementary feedstock along with biochar generated from egested frass to rear mealworms and achieve clean production while generating high-quality bioadsorbent for environment remediation and soil conditioning. Image 1 • Clean production study with 5 crop residues as feedstock of mealworms for insect biomass production. • The sequence of selection of feedstock was rice straw > corn straw > wheat straw based on consumption rates. • Mealworms ate more than 93% of rice straw and digested 49.78% lignin. • Biochars generated from mealworm frass adsorbed heavy metal ions effectively. • Biochar from rice straw frass showed best adsorption capacity and mechanisms were investigated. This research describes a novel clean production approach that agricultural waste residues (wheat straw, rice straw, rice bran, rice husk and corn straw) were used as feedstock to grow mealworms for insect biomass production; biochar was generated using mealworm frass; rice straw was the best feedstock tested based on digestibility and the frass derived showed optimal adsorption performance for heavy metal removal; and adsorption mechanisms were characterized. [ABSTRACT FROM AUTHOR]

Date seed derived highly mesoporous activated carbon is prepared for development of high electrochemical performances of capacitive deionization electrodes for NaCl removal. • Mesoporous activated carbon is derived from date seed biomass via pyrolysis technique. • The mesoporous structure and surface electrochemical properties can be tailored. • DSACs exhibit a higher capacitance of 400 F/g and surface area of 980.55 m2/g. • DSACs exhibit a high NaCl adsorption capacity of 22.2 mg/g with high desalination rate. • DSAC is considered a promising and economical material for desalination applications. The production of bio-char from agricultural waste is gaining greater attention for potential applications in energy and environment. In this work, the pyrolysis technique was used for the production of bio-char from date seed biomass. Further, the obtained bio-char was converted into porous activated carbon (DSAC) and the porosity was controlled by different KOH dosage. Key analytical instruments were used to investigate the physicochemical properties of the DSAC. Moreover, the electrochemical analysis of DSAC-1:1.5 sample showed a higher specific capacitance of 400 F/g at 10 mV/s with lower internal resistance and good stability. Importantly, high-performance capacitive deionization (CDI) electrodes were developed from DSAC-1:1.5 sample for desalting NaCl from saline solution. Presented CDI device showed a stable and reversible saltinsertion/de-insertion capacity of 22.5 mg g−1 at 1.2 V. This state-of-the-art DSAC-1:1.5 based CDI electrode largely surpasses common activated carbon and metal oxides nanocomposites. This present investigation demonstrates that the DSAC-1:1.5 is a feasible high-performance CDI electrode material for desalination applications. [ABSTRACT FROM AUTHOR]

The carbon black (CB) used in rubber manufacturing and the unsafe disposal of agricultural waste are one of the causes of environmental pollution. Indeed, the production of one ton of CB produces about 2.4 tons of carbon dioxide. The conversion of these agricultural wastes into biochar (Bi) and using them as a reinforcing material is one of the trends that achieve sustainability and promote environmentally sound. Herein, the modified biochar (MBi) was obtained by chemo-mechanical treatment utilizing stearic acid for Bi which was produced from the pyrolysis of citrus trees to enhance its dispersion in nitrile butadiene rubber (NBR) composite. In addition, the present study scrutinized the influence of synergism between the MBi and CB as a filler in the NBR composites. The characterization of as-prepared samples was carried out by tracing the surface morphology, particle size analyzer, and identification of chemical bonds, as well as rheological, mechanical, aging, and electrical conductivity properties. The rheological studies showed that the optimum vulcanization time (tc90) did not significantly prolong for MBi-filled composites, which sequentially higher the benefits of the study by reducing energy consumed and thus, the process cost. In addition, the surface morphology and the mechanical data have distinguished that MBi particles were well-distributed along the matrix, as revealed by the tensile properties of the final composites. The electrical conductivity results manifested that MBi did not adversely affect the enhancement of conductivity. Whereas, the permittivity was increased due to the interfacial polarization between the filler and rubber matrix. In conclusion, the innovative filled-MBi elastomer composite would pave the way for an eco-friendly product that is valid for various applications. • Using alternatives to carbon black to achieve sustainability and a clean environment. • Agricultural waste was converted into highly surface-activity biochar. • Surface modification of biochar using stearic acid to enhance its dispersion in NBR composite. • Converting waste into useful and sustainable products to achieve a win-win strategy. • Opened a new path by using biochar in rubber instead of the carbon black. [ABSTRACT FROM AUTHOR]

In heterogeneous electro-Fenton process, the design of electrocatalysts for in-situ generation of H 2 O 2 and efficient conversion to •OH remains a challenge. Herein, a simple one-step pyrolysis strategy has been developed to synthesize green and stable dual-functional electro-catalysts from agricultural wastes. The biochar of soybean roots (RSBC) with ample -COOH and C-O-C functional groups exhibited considerable capacity for H 2 O 2 production (21.6 mM at −0.4 V vs RHE), and the dual-functional electron-catalyst exhibits an excellent catalytic reaction for antibiotics removal (100 % cloroquine phosphate with k obs =0.035 min−1). The ultra-small MnO nanoclusters (<2 nm) in the biochar of Phytolacca americana leaves (LPBC) were the active center via the transfer of electrons between adsorbed H 2 O 2 and Mn atoms to produce reactive •OH, as identified by operando X-ray absorption fine structure (XAFS) spectroscopy and density functional theory calculations. This work provides a new direction in the design of dual-functional carbon cathode catalysts for environmental remediation. [Display omitted] • A Cost effective strategy to fabricate GDE derived from agricultural wastes for H 2 O 2 synthesis via 2e ORR. • Facile pyrolysis treatment for the synthesis of ultra-small MnOx cluster derived from Phytolacca americana leaves. • The ultra-small MnOx cluster (<2 nm) can efficiently convert H 2 O 2 into •OH in HEF system. • Extraordinary activity and stability of the dual-functional cathode for organic pollutant degradation. [ABSTRACT FROM AUTHOR]

Di(2-ethylhexyl) phthalate (DEHP) has been widely detected in soil, water, and sediment as a priority control pollutant. Immobilized microorganism technology is gradually mature and applied in production. Biochar prepared from agricultural wastes is an excellent immobilized carrier because of its porous structure and abundant functional groups. Environmental acidification was caused by degrading bacteria Arthrobacter sp. JQ-1 (JQ-1) respiration and acidic metabolites during DEHP degradation, which affected the passage life of microorganisms and the removal efficiency of DEHP. The mechanism of DEHP degradation by the combined action of JQ-1 and corn straw biochar (BC) at 600 °C was investigated, and bacterial viability, microenvironmental changes, and kinetic tests were performed in this research. Compared with biodegradation group alone, the degradation rate of DEHP in 1% biochar unloaded and loaded with JQ-1 increased by 18.3% and 30.9%, and its half-life decreased to 23.90 h and 11.95h, a reduction of 31.37 h. The percentage of detected living JQ-1 increased as biochar content increased when loading capacity was less than 1%. In which, (JQ-1-BC2) group was 4.1% higher than (JQ-1-BC1) group. Biochar has the ability to neutralize acidifying environmental pH due to its alkaline functional groups, including lactone group, –OH, –COO–. 1% biochar loaded with JQ-1 increased the pH of the microenvironment by 0.57 and alkaline phosphatase (AKP) activity by 0.0063 U·mL−1, which promoted the reduction of PA. Study suggested that biochar loaded with JQ-1 could simultaneously adsorb and degrade DEHP during the process of DEHP removal. Biochar could be used as a biological stimulant to increase abundance and metabolism, enhance the utilization of DEHP by JQ-1. Biochar (1% (w/v)) loaded with JQ-1 as DEHP removal material showed good performance. Biochar not only as an immobilized carrier, but also as a biostimulant, providing an effective strategy for the collaborative remediation of PAEs contaminated. Note: The interaction mechanism between biochar and bacteria for DEHP removal. [Display omitted] • The removal efficiency of DEHP is improved by the combined action of biochar and Arthrobacter sp. JQ-1 (JQ-1), which has a broad application prospect. • Biochar stimulates the growth, reproduction and metabolism of JQ-1. • The group of 1% biochar loaded with JQ-1 showed the promising performance in accelerating the restoration of DEHP. • Biochar stabilizes the pH of the microenvironment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The activated biochar (AB) and V 2 AlC-OH x MAX phase were used for Cr(VI) removal. • The asymmetric AB//V 2 AlC-OHx possesses both EDLC and pseudocapacitive behaviors. • The SEC of AB//V 2 AlC-OH x of 47.2 mg g−1 with removal efficiency of 99 % was observed. • The conversion of 60% Cr(VI) into Cr(III) during CDI processes enhances the removal efficiency. • Excellent cyclic performance for at least 20 adsorption–desorption cycles. The development of high-value-added biomass-derived carbonaceous as electrode material from agricultural wastes has received considerable attention. In this study, the activated biochar (AB) derived from the badam tree leaves (BTL) and functionalized 2D metal-carbide materials, V 2 AlC-OH x , have been successfully synthesized by alkaline treatment and microwave-assisted hydrothermal method, respectively, and then used as the asymmetric electrode materials for capacitive deionization application to remove Cr(VI) ions from aqueous solutions. The large specific surface area and the interconnected meso- and macro-porous channels of AB provide active sites and short ion diffusion paths to accelerate ion transport and electrosorption. In addition, the highly crystalline 2D architecture of V 2 AlC-OH x offers suitable lattice fringes for electron transfer. The conversion of Cr(VI) into Cr(III) on the surface of V 2 AlC-OH x , followed by the capture of Cr(III) onto the AB cathode has triggered the enhanced removal of Cr(VI). The AB//V 2 AlC-OH x asymmetric CDI device exhibits superior deionization performance for Cr(VI) removal with a specific electrosorption capacity of 47.2 mg g−1 and removal efficiency of 99 %. Excellent cyclic performance for at least 20 adsorption–desorption cycles is also observed, indicating the excellent durability of the fabricated materials. These results demonstrate that AB and V 2 AlC-OH x are promising CDI electrodes for the removal of metal ions and other hazardous pollutants from industrial effluents. [ABSTRACT FROM AUTHOR]