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Iron ore tailings (IOT) are industrial solid wastes that pose environmental threats. This study prepared IOT-biochar composite materials as multifunctional soil conditioners through an in-situ growth method. Biochar served as a carrier to improve the dispersity and reactivity of IOT in soil. The IOT-biochar composite (FeOT-BC) showed balanced impacts on soil properties, increasing pH, organic matter and available nutrients compared to IOT alone. This was due to the buffering effects of biochar. In pot experiments, FeOT-BC significantly promoted rice plant growth compared to IOT alone. The improvements were attributed to the improved soil fertility and increased microbial activities induced by biochar. The results suggest that integrating IOT with biochar can mitigate the negative effects of tailings and convert them into a value-added product. The biochar component can optimize the performance of IOT by moderating soil acidification, enhancing nutrient release from iron minerals, and stimulating microbial activities. The IOT-biochar composite materials integrate the functionalities of both components for optimized soil conditioning effects, providing a promising strategy for comprehensive tailings utilization. [ABSTRACT FROM AUTHOR]

The presence of antibiotics in wastewater has become a significant concern due to their potential environmental impact and contribution to antibiotic resistance. In this study, we investigated the degradation of tetracycline, a commonly used antibiotic, in wastewater using a system based on zero-valent nano iron assisted micro-nano bubbles (MB/nZVI). The synthesized nZVI-BC composite, consisting of nano zero-valent iron particles loaded onto phosphoric acid-activated biochar, served as an efficient adsorbent for tetracycline removal. Our findings revealed that the combination of MBs and nZVI significantly enhanced the degradation efficiency of tetracycline. The MB/nZVI system exhibited the highest removal rate of 82.81% after a 2 h reaction, surpassing the performance of MB alone, nZVI-BC alone, and conventional bubble (CB)/nZVI-BC systems. Furthermore, the MB/nZVI system showed superior degradation performance at a dosage of 25 g/L and an MB flow rate of 30 mL/min. The pH condition had no significant effect on tetracycline degradation in the MB/nZVI system. Our results demonstrate that the use of MB/nZVI has the potential to be a sustainable and efficient approach for the remediation of tetracycline-contaminated wastewater. [ABSTRACT FROM AUTHOR]

Smart agro-practices over the years have revolutionized the agriculture sector and promoted the concept of sustainable agriculture. One such practice is use of agro-waste biochar in agricultural, environmental, and climatic operations. The viability of using a biochar-based nanocomposite as a support fertilizer for the gradual release of nitrogen, potassium, and phosphorus in various media is examined in this study. The banana peel biochar (BPBC) and its nanocomposite (BNF) were prepared using a simple yet comprehensive chemical process. Synthesized materials were evaluated using FT-IR and SEM/EDX. Physical attributes as well as fertilizer basic characteristics were determined and prepared nanocomposite demonstrated noticeably better water absorbance ratio (68%), equilibrium water content (78.97%), and swelling ratio (3.64 g g−1) than biochar, which is advantageous for preserving soil water levels. The salt index values (0.087mmhos/cc) of the created nanocomposite performed better when compared to the conventional fertilizers due to their safer application. Long-term availability of all doped minerals to the plants, during experimental cycle, was revealed by slow-release nutrient studies in water and soil, which is ideal for promoting germination and growth. The findings of this research revealed that prepared BNF showed improved germination parameters i.e., time for 50% germination (3.4, 3.3, 4.4 days), germination index (3.1, 3.5, 2.4), final germination percentage (91.7, 100, 83.3%), mean germination time (4.0, 3.9, 4.9 days), for cucumber, broccoli and okra, respectively. In addition to that the prepared BNF facilitated enhanced shoot and root length in all the three vegetables as compared to conventional fertilizers. The dose optimization studies depicted that best results of germination as well as plant growth parameters are facilitated by BNF (37.5 kg/ha) owing to enhancement in soil quality by supplying additional organic matter in addition to provision of nutrients on slow-release. [ABSTRACT FROM AUTHOR]

In this work, the adsorption capacity of the biochar obtained from Pinus patula biomass micro-gasification was studied using malachite green (MG) as the probe pollutant. For this purpose, the biomass type (wood pellets and chips) was selected to produce two kinds of biochar (BC). Afterwards, the effects of the adsorbent dose (6, 9 and 12 g/L), the solution pH (4, 7 and 10) and the BC particle size distribution (150–300, 300–450 and 450–600 μ m) for the maximization of the MG retention by the selected BC were evaluated using a faced-centered central composite design, as response surface methodology. The results indicated that the BC derived from wood chips (BWC) exhibited a higher MG dye adsorption capacity than the BC obtained from the wood pellets (BWP) gasification under the same operating conditions after having reached the equilibrium. A second-order regression model was built for describing the MG adsorption behaviour by BWC under the considered experimental domain. The model, which was validated, resulted to be statistically significant and suitable to represent the MG adsorption by the studied BC with a p-value of 0.00 and a correlation coefficient (R2) of 95.59%. Additionally, a three-dimensional response surface graph and a contour plot were utilized to analyze the interaction effects between the factors influencing the adsorption system and to discern the optimal operating conditions for the use of BWC. The maximal MG dye retention (99.70%) was found to be at an adsorbent dose, pH solution and a particle size distribution of 9.80 g/L, 10 and from 150 to 300 μ m, respectively. Therefore, the BWC tested can be utilized for the treatment of water polluted with dyes, contributing to the establishment of a circular economy. [ABSTRACT FROM AUTHOR]

Global warming have become a stress condition due to the generation of greenhouse gases from the burning of fossil fuels and deforestation with the industrial revolution. Climate change induces biotic and abiotic stress conditions which badly disturb the yield of crops with leading to the biochemical and physiological damages to plants. Therefore; this study investigated the capability of Morus alba L. wood biochar and plant growth promoting rhizobacteria PG1 (Pseudomonas sp.) and PG2 (Staphylococcus haemolyticus) to alleviate the drought condition in Brassica napus L. plant. In the current research work, the combined application of plant growth promoting rhizobacteria (PGPRs) and biochar triggered an enhancement in physicochemical properties of soil including %field capacity, water use efficiency, germination parameters including Timson germination index, final emergence percentage, mean germination time, final germination percentage, germination energy, mean emergence time, germination rate index and vegetative parameters including seed vigor indexes (SVI-I & SVI-II) and plant height stress index. Inoculation and co-inoculation of PGPRs and biochar positively promote the canola plant growth even under induce drought stress condition. A positive increase in B. napus biomass including leaf area, plant height and root growth and its dry and fresh mass at p < 0.05 level, which support the effectiveness of this approach. Results also showed that Staphylococcus haemolyticus individually and in combination with biochar even under stress condition promote canola plant growth more than Pseudomonas sp. We concluded that under stressors, co-application of PGPRs and biochar could be an operative approach for enhancing plant productivity and its development. [ABSTRACT FROM AUTHOR]

Recently, scientists have shown interest in utilizing biochar made from natural sources to enhance various photovoltaic technologies. In this study, Zinc-Bis-8-hydroxyquinoline (Zn-Hq2) was mixed with 10 % biochar obtained from red sea microalgae (Chlorophyta) using a microwave combustion process. This mixture was then used as a novel photoactive layer in a solar cell. The structural properties of Zn-Hq2@BC were analyzed by XRD, FTIR, HRTEM, and SEM. The analysis showed that Zn-Hq2@BC had evenly distributed nano-rods within the BC nanopores network, with widths ranging from 26.94 to 30.90 nm and lengths ranging from 136.43 to 192.38 nm. When measuring dark current density-voltage, it was found that Zn-Hq2@BC/n-Si showed better-rectifying characteristics compared to pristine Zn-Hq2/n-Si, with a higher rectification ratio. The results also showed that the current density and voltage at the maximum power point increased to 5.63 mA/cm2 and 0.45 V, respectively, due to the activation of the biochar. When exposed to light, the addition of approximately 10 % biochar resulted in a 15 % increase in fill factor and a 92 % increase in power conversion efficiency. This is because biochar helps introduce extra charge carriers into the material, thus improving charge transport and reducing recombination losses. These findings reveal the positive effects of microalgae-derived biochar and indicate potential applications of Zn-Hq2 in solar cells. [ABSTRACT FROM AUTHOR]

A novel and efficient process for the removal of Ce(IV) from aqueous solutions was sought, and a new magnetic porous biochar (PBC/ZF) was synthesized by loading ZnFe 2 O 4 (ZF) onto porous biochar (PBC) using a one-step hydrothermal method. The SEM observation of the external features showed that the cubic spinel structured ZnFe 2 O 4 (ZF) particles were loaded onto the porous biochar (PBC) surface. This resulted in a composite with superb paramagnetic properties as well as higher adsorption properties. In addition, the microstructure was characterized by FTIR, which demonstrated that the target material was supplied with a large amount of carboxyl groups (-COOH) by citric acid during the synthesis process. The BET showed that the target material had a higher specific surface area than ZnFe 2 O 4 with PBC, confirming the successful preparation of the target material after activation of the biomass using ZnCl 2 immersion as well. The effect of different factors on the adsorption effect was investigated experimentally. The results showed that PBC/ZF had a good adsorption effect on Ce(IV) with a short adsorption equilibrium time and a maximum adsorption capacity of 228.9 mg/g at room temperature with lower acidity (pH = 2.5). The adsorption kinetics and isotherm analysis showed that the Ce(IV) adsorption process fitted well with the quasi-secondary kinetic model and Langmuir model. It indicates that the process is a single molecular layer adsorption process. It was demonstrated that PBC/ZF also has high removal rate for high concentration Ce(IV) solution, and it is easy for solid-liquid separation under the action of applied magnetic field after adsorption. It provides a new treatment method and theoretical support for the adsorption treatment technology of Ce (IV) wastewater. [ABSTRACT FROM AUTHOR]

Biochar was proposed as a novel carbon source for synthesizing Ti 3 SiC 2 powder with high purity by a simple pressureless sintering at 1673 K, and Ti 3 SiC 2 grains exhibited the typical nanolayered structure. The oxidation behavior of Ti 3 SiC 2 powder showed the parabolic law during isothermal oxidation from 1273 K to 1473 K. Dense and continuous oxidation layer consisting of mixed TiO 2 and SiO 2 was formed rapidly on the surface of Ti 3 SiC 2 particles as a diffusion barrier, which effectively retarded the inward diffusion of oxygen, conferring good oxidation resistance of the powder. [ABSTRACT FROM AUTHOR]

Phosphorus, P deficiency by adsorption and fixation of applied P is a critical problem in the tropical soils coupled with wastage of agricultural land and potential nutrients from crop residues' decomposition necessitates conservancy and sustainable management. Maize stover biochar (mB) and sawmill waste biochar (sB) pyrolysed for 60-minute at 460 °C using Top-Lit Up Draft (TLUD) carbonizer were characterized by morphological, elemental and proximate properties analysed by Scanning Electron Microscope (SEM), CHNS Elemental Analyser and appropriate methods, respectively. Phosphorus (P) adsorption potential of the biochars in charnockite-originated soils were evaluated using adsorption isotherms after adding biochars at 0, 5, 10 and 20% (w/w) with concentrations of 0, 15, 30, 60, 90, 120, 150 mg P/L. SEM showed macropores (>50 nm) embedded biochars, with higher elemental C and H in sB while mB contained higher N, S, O, available P and pH. P-adsorption decreased inconsistently with increasing biochar rates resulting in P-desorption. Low Langmuir adsorption maximum (Qm) were recorded (−0.0350 to 0.1250 mg kg−1) mostly with negative separation factors (R L) and the adsorption process were favourable for mB amended soils having Freundlich heterogeneity factor (n F) of 4.476–9.634 but not for sB amended soils (n F = 0.638–2.812). Biochar production conserved nutrient loss and potentially reduced soil P fixation. [ABSTRACT FROM AUTHOR]

Under the circumstances of serious environmental challenges and energy crises, it is of utmost importance to produce fuels and chemicals from renewable biomass and organic wastes. Biochar as a bioproduct from thermochemical conversion of biomass has attracted exponential research interest in recent years due to the abundance of its precursor (biomass resources) and its adaptability in different chemical reaction systems. Undoubtedly, it is essential to attain an in-depth understanding of the physiochemical properties and functionalization of biochar catalysts to further improve their catalytic activity, selectivity and stability in the reactions. However, until now, only a few reports are accessible on the use of biochar as a catalytic support material and/or a standalone catalyst in thermochemical biomass conversion to produce high-quality biofuels. Thus, the key objective of this review article is to summarize and discuss the latest progress in biochar production, modification, activation and functionalization by understanding its physical chemistry, composition and application in catalytic processes. This review article provides insights into the thermochemical and hydrothermal production of biochar as well as the engineering and process optimization aspects for value-added biofuel production and decarbonization. [Display omitted] • Effects of biomass composition and process conditions on biochar are reviewed. • Systematic discussion on biochar functionality as bio-based catalyst support is made. • Insights into the modification of biochar targeting optimal performance are shown. • Comparative analysis of biochar-based catalytic pyrolysis, gasification and liquefaction. • The significance of activation of biochar for enhanced functionality is justified. [ABSTRACT FROM AUTHOR]

Biochar materials have wide applications in soil improvement/remediation, water pollution control, gas storage, and heterogeneous catalysis, while usually suffering from low surface areas and harsh preparation conditions. In this study, a green, environmentally friendly, and low-cost biochar catalyst (PAP-MEPP-C) was prepared by thermochemical treatment of lignin-derived monomers at a low temperature (80 °C), and further developed for high-efficiency production of biodiesel from non-edible Jatropha oil (J O). The characterization results showed that the structure of the PAP-MEPP-C biochar catalyst was layered and 3D structure, and its acidity could be controlled by changing the monomeric composition. The reaction conditions of preparing biodiesel catalyzed by PAP-MEPP-C were optimized by the response surface method, and the obtained maximum biodiesel yield was 97.2%. The kinetics of the (trans)esterification reaction over the developed biochar catalyst PAP-MEPP-C was studied, and its superior catalytic performance to other tested acid catalysts could be supported by a relatively lower activation energy (36 kJ mol−1). In addition, the biochar catalyst was highly stable and could be recycled four times with more than 90% biodiesel yield. [Display omitted] • A novel 3D layered biochar with tunable acidity was prepared by treatment at 80 °C. • Response surface method optimized the catalytic conditions of prepared biochar. • The yield of biodiesel from Jatropha oil over the biochar catalyst was up to 97.2%. • The biochar catalyst had good reusability with biodiesel yield of > 90% after 4 cycles. • The biochar catalyst is active for producing biodiesel from oils with high acid value. [ABSTRACT FROM AUTHOR]

Herein, a peony-shaped nanocomposite (P-ZnO/BC) was facilely developed by incorporating ZnO with Hemp stalk derived biochar (BC) via two-step sequential solvothermal procedure and used for photocatalytic degradation of organic contaminants. The as-prepared P-ZnO/BC presents preferential (100) crystal orientation, suitable electronic energy level, and distinct mesoporous distribution as well as large specific surface area. Thereby, the optimal P-ZnO 0.3 /BC (weight ratio of 3:7 for ZnO:BC) shows higher photocatalytic activity with degradation efficiency as high as 94.5 % toward methylene blue (MB) within 120 min, whereas the ZnO and BC merely deliver 6.3 % and 63.5 %, respectively. Obviously, the superior contaminants removal properties of P-ZnO 0.3 /BC can be attributed to the synergistic effect of adsorption of BC and photocatalysis of ZnO. Also, this can be associated with the improved adsorption, accelerated charges (e-/h+ pairs) transportation and reduced e-/h+ pairs recombination of P-ZnO 0.3 /BC. The reactive radicals scavenging experiments and ESR measurements confirm that the main reactive species are hydroxyl radicals (•OH) and holes (h+). Furthermore, P-ZnO 0.3 /BC displays desirable reusability and better universal applicability toward other organic dyes and antibiotics removal. Moreover, the possible degradation mechanism and pathway were also inferred by analyzing the intermediates via liquid chromatography mass spectrometry (LC-MS) technique. In conclusion, this work provides a fundamental insight via integrating ZnO with low-cost BC for efficient removal of the refractory organic pollutants. [Display omitted] • A P-ZnO/BC was facilely synthesized by incorporating ZnO with biochar. • The P-ZnO/BC has a unique peony-shaped with dominant {100} facets. • The optimal P-ZnO0.3/BC showed optimal MB removal rate to 94.5 %. • The P-ZnO0.3/BC also shows significant reusability and universal applicability. [ABSTRACT FROM AUTHOR]

Coastal wetlands possess significant carbon storage capabilities. However, in coastal soil-plant systems augmented with biochar and microorganisms, the mechanisms of these amendments and carbon participation remain unclear. This study utilized pot experiments to explore how Enteromorpha prolifera biochar and Arbuscular mycorrhizal fungi (AMF) affect soil organic carbon (SOC), carbon-related microbes, photosynthetic and osmotic system of Suaeda salsa. The results showed biochar reduced exchangeable sodium percentage by 6.9% through adsorption and ion exchange, and increased SOC content by 34.4%. The abundance of carbon-related microorganisms (Bacteroidota and Chloroflexi) was increased and carbon metabolizing enzyme (cellulase and sucrase) activity in the soil was enhanced. AMF significantly improved plant growth compared with CK, as evidenced by the enhanced dry weight by 2.34 times. A partial least squares pathway model (PLS-PM) and correlation analysis suggested that the combined effect of biochar and AMF could be outlined as two pathways: soil and plant. Biochar increased SOC, improved the growth of soil carbon metabolizing microorganisms, and further promoted the activity of carbon-related enzymes. Additionally, AMF facilitated nutrient absorption by plants through root symbiosis, with biochar further enhancing this process by acting as a nutrient adsorber. These combined effects of biochar and AMF at soil and plant level enhanced the photosynthetic process of Suaeda salsa. The transport of photosynthetic products to the roots can increase the carbon storage in the soil. This study provides quantitative evidence supporting the increase of carbon storage in coastal wetland soil-plant systems through a combined application of biochar and AMF. [Display omitted] • PLS-PM revealed the influence path of biochar and AMF on salt tolerance of plants. • Biochar and AMF took affect respectively at the soil and plant level. • Biochar acted as a nutrient adsorber to promote nutrient uptake by AMF. • Biochar and AMF enhanced photosynthesis and alleviated osmotic stress of plants. [ABSTRACT FROM AUTHOR]

A significant amount of effort has been devoted to the utilization of biochar-based catalysts in the treatment of wastewater. By virtue of its abundant functional groups and high specific surface area, biochar holds significant promise as a catalyst. This article presents a comprehensive systematic review and bibliometric analysis covering the period from 2009 to 2024, focusing on the restoration of wastewater through biochar catalysis. The production, activation, and functionalization techniques employed for biochar are thoroughly examined. In addition, the application of advanced technologies such as advanced oxidation processes (AOPs), catalytic reduction reactions, and biochemically driven processes based on biochar are discussed, with a focus on elucidating the underlying mechanisms and how surface functionalities influence the catalytic performance of biochar. Furthermore, the potential drawbacks of utilizing biochar are also brought to light. To emphasize the progress being made in this research field and provide valuable insights for future researchers, a scientometric analysis was conducted using CiteSpace and VOSviewer software on 595 articles. Hopefully, this review will enhance understanding of the catalytic performance and mechanisms pertaining to biochar-based catalysts in pollutant treatment while providing a perspective and guidelines for future research and development efforts in this area. [Display omitted] • A literature review and bibliometric analysis of BCs for wastewater treatment was conducted. • The methods for modifying biochar and their utilization in advanced technologies are examined. • The effect and mechanism of surface functionality on catalytic efficiency of BCs were clarified. • The potential drawbacks of BCs utilization were brought to light. [ABSTRACT FROM AUTHOR]

Biosynthesized nanocomposites, particularly those incorporating carbon-based materials, exhibit exceptional tunability and multifunctionality, surpassing the capabilities of conventional materials in these aspects. Developing practical solutions is critical to address environmental toxins from pharmaceuticals, heavy metals, pesticides, and dyes. Biomass waste is a readily available carbon source, which emerges as a promising material for producing biochar due to its inherent advantages: abundance, low cost, and environmentally friendly nature. This distribution mainly uses carbon-based materials (CBMs) and biomass waste in wastewater treatment. This review paper investigates several CBM types, including carbon aerogels, nanotubes, graphene, and activated carbon. The development of bio-derived carbon-based nanomaterials are discussed, along with the properties and composition of carbon materials derived from biomass waste and various cycles, such as photodegradation, adsorption, and high-level oxidation processes for natural remediation. In conclusion, this review examines the challenges associated with biochar utilization, including cost, recovery, and practical implementation. [Display omitted] • The primary characteristics, methodologies, and usage of biochar-based carbon for environmental remediation. • The use of carbon-based materials derived from biomass. • This review also focuses on various carbon-based materials and combination strategies. • Biomass derived carbon nanocomposites are cost effective, emerging and promising technique. • Composites made from biochar used to clean up contaminated areas in a sustainable way. [ABSTRACT FROM AUTHOR]

The detrimental effects of microplastics (MPs) on soil microbial and elemental raise significant environmental concerns. The potential of remediation with biochar to mitigate these negative impacts remains an open question. The remediation effects of biochar derived from corn and cotton straw on MPs concerning soil microorganisms and element cycling were investigated. Specifically, biochar induced substantial remediations in microbial community structure following MP exposure, restoring and fortifying the symbiotic network while exerting dominance over microbial community changes. A combined treatment of biochar and MPs exhibited a noteworthy increase in the abundance of NH 4 +, NO 3 −, and available phosphorous by 0.46–2.1 times, reversing the declining trend of dissolved organic carbon, showing a remarkable increase by 0.36 times. This combined treatment also led to a reduction in the abundance of the nitrogen fixation gene nifH by 0.46 times, while significantly increasing the expression of nitrification genes (amoA and amoB) and denitrification genes (nirS and nirK) by 22.5 times and 1.7 times, respectively. Additionally, the carbon cycle cbbLG gene showed a 2.3-fold increase, and the phosphorus cycle gene phoD increased by 0.1-fold. The mixed treatment enriched element-cycling microorganisms by 4.8–9.6 times. In summary, the addition of biochar repaired the negative effects of MPs in terms of microbial community dynamics, element content, gene expression, and functional microbiota. These findings underscore the crucial role of biochar in alleviating the adverse effects of MPs on microbial communities and elemental cycling, providing valuable insights into sustainable environmental remediation strategies. [Display omitted] • Negative impact of microplastics on soil microbial communities was confirmed. • Negative impact of microplastics on soil element cycles was confirmed. • Biochar played a leading role when coexisting with microplastics. • Biochar mitigated microbes and element cycles changes caused by microplastics. [ABSTRACT FROM AUTHOR]

Effective dewatering is vital for both sludge treatment and resource recovery. This study focuses on converting post-anaerobic digested sludge into biochar to enhance sludge dewatering. The sludge-derived biochar is further modified with polyacrylamide (PAM-ADBC) and applied with sulfuric acid-modified montmorillonite (HMTS) for better performance. Significant advancements in dewatering were noted, even at reduced HMTS (0.1 g/g DS) and PAM-ADBC (25 g/kg DS) dosages. These improvements resulted in a remarkable 41.96% enhancement in capillary suction time (17.2 s) and a notable 20.26% reduction in moisture content (66.33%), respectively, all while maintaining a stable pH level. HMTS, with leached cations, improved dewatering by decomposing the extracellular polymeric substance structure through electro-neutralization to release the internal bound water within sludge flocs. Simultaneously, PAM-ADBC coagulated decomposed sludge particles into larger flocs to form a skeletal structure with itself to discharge internal water in compression dewatering. This study introduces a resource recovery method for anaerobically digested sludge and highlights its potential for sustainable utilization. [Display omitted] • A novel PAM modified anaerobic digested sludge-based biochar (PAM-ADBC) prepared. • A sulfuric acid modified montmorillonite (HMTS) prepared. • Improvement achieved in capillary suction time (by 42%) and moisture content (20%). • PAM-ADBC and HMTS exhibited synergistic enhancing effects on sludge dewatering. [ABSTRACT FROM AUTHOR]

This study presents the successful synthesis of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar for efficient removal of U(VI) from aqueous solutions. A novel synthesis approach involving phosphate thermal polymerization-hydrothermal method was employed, deviating from conventional pyrolysis methods, to produce hydrothermal biochar. The combination of solvent thermal polymerization technique with hydrothermal process facilitated efficient loading of layered double hydroxide (LDH) components onto the biochar surface, ensuring simplicity, low energy consumption and enhanced modifiability. Bamboo waste was utilized as the precursor for biochar, highlighting its superior green and sustainable characteristics. Additionally, this study elucidated the interactions between phosphate-modified hydrothermal biochar and LDH components with U(VI). Physicochemical analysis demonstrated that the composite biochar possessed a high surface area and abundant oxygen-containing functional groups. XPS and FTIR analyses confirmed the efficient adsorption of U(VI), attributed to chelation interactions between phosphate groups, magnesium hydroxyl groups, hydroxyl groups and U(VI), as well as the co-precipitation of U(VI) with multi-hydroxyl aluminum cations captured by LDH. The composite biochar reached adsorption equilibrium with U(VI) within 80 min and exhibited excellent fitting to the pseudo-second-order kinetic model and Langmuir model. Under conditions of pH = 4 and 298 K, it displayed significantly high maximum adsorption capacity of approximately 388.81 mg g⁻1, surpassing untreated biochar by 17-fold. The adsorption process was found to be endothermic and spontaneous and even after five consecutive adsorption-desorption cycles, the removal efficiency of U(VI) remained stable at 75.46%. These findings underscore the promising application prospects of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar in efficiently separating U(VI) from uranium-containing wastewater, emphasizing its environmental and economic value. [Display omitted] • An innovative combined solvent thermal polymerization and water bath strategy. • Environmental value and economic potential of bamboo waste-derived adsorbents. • Interaction of -PO 4 groups and LDH components with U(VI) is critical for adsorption. • Hydrothermal biochar grafted phosphate-loaded Mg–Al layered double hydroxide for efficient removal of hexavalent uranium. [ABSTRACT FROM AUTHOR]

Feedstock characteristics impact biochar physicochemical properties, and reproducible biochar properties are essential for any potential application. However, in most articles, feedstock aspects (i.e., taxonomic name of the species, part of the plant, and phenological phase) are scarcely reported. This research aimed at studying the effect of species and phenological stage of the feedstock on the properties of the derived biochars and, thus, adsorption capacities in water treatment. In this study, we analysed the anatomical characteristics of three different woody bamboo species [ Guadua chacoensis (GC) , Phyllostachys aurea (PA) , and Bambusa tuldoides (BT)] in culms harvested at two different phenological phases (young and mature), and statistically correlated them with the characteristics of the six derived biochars, including their adsorption performance in aqueous media. Sclerenchyma fibres and parenchyma cells diameter and cell-wall width significantly differed among species. Additionally, sclerenchyma fibres and parenchyma cell-wall width as well as sclerenchyma fibre cell diameters are dependent on the phenological phase of the culms. Consequently, differences in biochar characteristics (i.e., yield and average pore diameter) were also observed, leading to differential methylene blue (MB) adsorption capacities between individuals at different phenological phases. MB adsorption capacities were higher for biochar produced from young culms compared to those obtained from matures ones (i.e., GC: 628.66 vs. 507.79; BT: 537.45 vs. 477.53; PA: 477.52 vs. 462.82 mg/g), which had smaller cell wall widths leading to a lower percentage of biochar yield. The feedstock anatomical properties determined biochar characteristics which modulated adsorption capacities. [Display omitted] • Culms and biochars were anatomically (LM and SEM), elementary (CHNS), and statistically analysed (GLM). • Feedstock's anatomical variables define biochar physicochemical properties. • Biochar yield and average pore diameter differed with bamboo species and phenological phases. • Methylene blue adsorption capacities were higher when biochar came from young culms. • Young culms had thinner cell wall widths and lower biochar yield. [ABSTRACT FROM AUTHOR]

The simultaneous removal of anionic and cationic heavy metals presents a challenge for adsorbents. In this study, acetate (Ac-) was utilized as the intercalating anion for layered double hydroxide (LDH) to prepare a novel biochar composite adsorbent (Ac-LB) designed for the adsorption of Pb(II), Cu(II), and As(V). By utilizing Ac- as the intercalating anion, the interlayer space of the LDH was enlarged from 0.803 nm to 0.869 nm, exposing more adsorption sites for the LDH and enhancing the affinity for heavy metals. The results of the adsorption experiments showed that the adsorption effect of Ac-LB on heavy metals was significantly improved compared to the original FeMg-LDH modified biochar composites (LB), and the maximum adsorption capacity of Pb(II), Cu(II), and As(V) were 402.70, 68.50, and 21.68 mg/g, respectively. Wastewater simulation tests further confirmed the promising application of Ac-LB for heavy metal adsorption. The analysis of the adsorption mechanism revealed that surface complexation, electrostatic adsorption, and chemical deposition were the main mechanisms of action between heavy metals (Pb(II) and Cu(II)) and Ac-LB. Additionally, Cu(II) ions underwent a homogeneous substitution reaction with Ac-LB. The adsorption process of As(V) by Ac-LB mainly relied on complexation and ion-exchange reactions. Lastly, the modification of the LDH structure by Ac− as an intercalating anion, thereby increasing the affinity for heavy metals, was further illustrated using density-functional theory (DFT) calculations. [Display omitted] • Preparation of a composite with acetate as LDH intercalation ion. • Acetate as intercalating ion improved the adsorption capacity of the FeMg-LDH. • The mechanism of heavy metal adsorption was discussed. • The experimental results were verified by DFT calculation. [ABSTRACT FROM AUTHOR]

Anaerobic digestion of floated paperboard sludge (PS) cake suffers from volatile fatty acids (VFAs) accumulation, nutrient unbalanced condition, and generation of digestate with a risk of secondary pollution. To overcome these drawbacks, sewage sludge (SS) was added to PS cake for biogas recovery improvement under a co-digestion process followed by the thermal treatment of solid fraction of digestate for biochar production. Batch experimental assays were conducted at different SS:PS mixing ratios of 70:30, 50:50, 30:70, and 20:80 (w/w), and their anaerobic co-digestion performances were compared to the mono-digestion systems at 35 ± 0.2 °C for 45 days. The highest methane yield (MY) of 241.68 ± 14.81 mL/g COD removed was obtained at the optimum SS:PS ratio of 50:50 (w/w). This experimental condition was accompanied by protein, carbohydrate, and VFA conversion efficiencies of 47.3 ± 3.2%, 46.8 ± 3.2%, and 56.3 ± 3.8%, respectively. The synergistic effect of SS and PS cake encouraged the dominance of Bacteroidota (23.19%), Proteobacteria (49.65%), Patescibacteria (8.12%), and Acidovorax (12.60%) responsible for hydrolyzing the complex organic compounds and converting the VFAs into biomethane. Further, the solid fraction of digestate was subjected to thermal treatment at a temperature of 500 °C for 2.0 h, under an oxygen-limited condition. The obtained biochar had a yield of 0.48 g/g dry digestate, and its oxygen-to-carbon (O/C), carbon-to-nitrogen (C/N), and carbon-to-phosphorous (C/P) ratios were 0.55, 10.23, and 16.42, respectively. A combined anaerobic co-digestion/pyrolysis system (capacity 50 m3/d) was designed based on the COD mass balance experimental data and biogenic CO 2 market price of 22 USD/ton. This project could earn profits from biogas (12,565 USD/yr), biochar (6641 USD/yr), carbon credit (8014 USD/yr), and COD shadow price (6932 USD/yr). The proposed project could maintain a payback period of 6.60 yr. However, further studies are required to determine the associated life cycle cost model that is useful to validate the batch experiment assumptions. Image created with Biorender.com under Agreement number: VB26T4VGHU. [Display omitted] • Paperboard sludge cake and sewage sludge improved methanogenic community. • Optimum PS:SS ratio was 50:50 (w/w), giving methane yield of 242 mL/g COD removed. • Proteiniphilum , Brevundimonas , Methanobacterium were dominant genera. • Digestate was pyrolyzed into biochar with O/C, C/N, C/P ratios of 0.55, 10.23, 16.42 • Combined anaerobic co-digestion/pyrolysis is feasible with 6.60 yr payback period. [ABSTRACT FROM AUTHOR]

The enrichment of phosphorus (P) and nitrogen (N) in aquatic systems can cause eutrophication. Moreover, P rocks may become exhausted in the next 100 years. A slow-release fertilizer called struvite (MgNH 4 PO 4.6H 2 O) can reduce surface runoff. However, the high cost of raw material or chemicals is a bottleneck in their economical production. Therefore, incinerated sewage sludge ash, food wastewater, and bittern were combined as the sources of P, N, and Mg, respectively. Sawdust biochar was used to enhance the adsorptive recovery of nutrients. First, recovery kinetics was studied by comparing bittern-impregnated biochar (BtB) with the Mg-impregnated biochar (MgB). Subsequently, the synergistic physical and chemical interactions were observed for P and N recovery. Almost complete PO 4 3–P recoveries were achieved within 10 min for both biochars. However, NH 4 +-N recovery was stable after 2 h, with 26% recovery by MgB and 20% recovery by BtB. Biochars activated with steam (steam-activated biochar) and KOH (KOH-activated biochar) gave superior activities to those of unactivated biochars and activated carbon (AC) nutrient recovery and struvite purity. Moreover, the activated biochars showed a lower risk of surface runoff, similar to that of AC. Therefore, activated biochars can be used as an alternative to AC for economical struvite production from a combination of wastewater sources. [Display omitted] • Phosphorus and nitrogen enrichment spur eutrophication; P rocks may vanish within a century. • Struvite (MgNH 4 PO 4.6H 2 O) reduces runoff but faces cost hurdles. • Incinerated sewage sludge ash, food wastewater, and bittern cut expenses for P, N, and Mg; sawdust biochar aids recovery. • BtB and MgB show rapid PO 4 3–P recovery in 10 min, stable NH 4 +-N recovery in 2 h. • Steam- and KOH-activated biochars surpass unactivated ones and AC, offering economical struvite from wastewater. [ABSTRACT FROM AUTHOR]

The safety and health of aquatic organisms and humans are threatened by the increasing presence of pollutants in the environment. Endocrine disrupting chemicals are common pollutants which affect the function of endocrine and causes adverse effects on human health. These chemicals can disrupt metabolic processes by interacting with hormone receptors upon consumptions by humans or aquatic species. Several studies have reported the presence of endocrine disrupting chemicals in waterbodies, food, air and soil. These chemicals are associated with increasing occurrence of obesity, metabolic disorders, reproductive abnormalities, autism, cancer, epigenetic variation and cardiovascular risk. Conventional treatment processes are expensive, not environment friendly and unable to achieve complete removal of these harmful chemicals. In recent years, biochar from different sources has gained a considerable interest due to their adsorption efficiency with porous structure and large surface areas. biochar derived from lignocellulosic biomass are widely used as sustainable catalysts in soil remediation, carbon sequestration, removal of organic and inorganic pollutants and wastewater treatment. This review conceptualizes the production techniques of biochar from lignocellulosic biomass and explores the functionalization and interaction of biochar with endocrine-disrupting chemicals. This review also identifies the further needs of research. Overall, the environmental and health risks of endocrine-disrupting chemicals can be dealt with by biochar produced from lignocellulosic biomass as a sustainable and prominent approach. [Display omitted] • Valorization of lignocellulosic biomass as biochar for EDC adsorption was explored. • Biomass criteria, properties and benefits of biochar were conscientiously reviewed. • Biochar mediated removal of EDC has been critically evaluated. • Engineered lignocellulosic based biochars' binding mechanisms to EDC investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new idea for the removal of 17β-E2 from was were offered. • Optimal degradation terms and influence factors were investigated in the system. • Reaction mechanism, degradation products, and toxicity analysis were clarified. • Reaction sites of 17β-E2 susceptible to be attacked were predicted by DFT. Estrogens are widely detected in the environment and can strongly disrupt the endocrine systems of humans in extremely minute concentrations. Therefore, it is imperative to address possible 17β-estradiol (17β-E2) pollution and explore resourceful utilization methods from cow manure, which contains estrogen. In this study, cow manure biochar (CBC) was successfully prepared and used for the activation of peroxymonosulfate (PMS), attaining a 17β-E2 degradation rate exceeding 90 % within a mere 10 min. Optimal degradation performance was achieved at 2 mg/L 17β-E2 concentration, 2 mM PMS concentration, and 0.2 g/L CBC concentration. Furthermore, the influence of biochar-activated PMS on estrogen degradation was thoroughly explored under various environmental factors. The key reactive oxygen species were identified as O 2 – and 1O 2 by conducting quenching experiments and delayed experiments. This study elucidated the occurrence of direct electron conduction and the generation of reactive oxygen species to degrade 17β-E2. Furthermore, the phenol group on the benzene ring and the hydroxyl group on the cyclopentane in 17β-E2 as the susceptible reaction sites during the degradation process were predicted using density functional theory (DFT). This study presents promising opportunities for the resourceful utilization of cattle manure and the mitigation of environmental pollution by endocrine disruptors. [ABSTRACT FROM AUTHOR]

• Grape seeds waste biochar activated with H 3 PO 4 develops a specific area over 500 m2/g. • The biochar's adsorption capacity of paracetamol drug residue from water exceeds 17 mg/g. • DFT elucidates the interaction mechanism between the drug residue and the biochar. • DLPNO/CCSD reveal strong interactions between P biochar groups and drug acetamide. • Thermodynamics analysis shows an endothermic, spontaneous drug residue physisorption. Activated carbon (AC) derived from grape seeds wastes and chemically activated with phosphoric acid was employed to remove paracetamol (PCT); from an aqueous solution; as a pharmaceutical compound model. The AC was characterized using several techniques, and a series of batch adsorption experiments were conducted. Additionally, a theoretical study investigated the interactions of PCT with various functional groups present on the AC surface. The results demonstrated that the developed AC possessed a well-developed pore structure and a high specific surface area (S BET = 543 m2/g). The AC also exhibited an acidic surface and a low pH pzc (2.5). Adsorption experiments revealed that the pseudo-second-order (PSO) and Freundlich models provided the best fits for experimental kinetic and equilibrium data, respectively. The maximum adsorption capacity of AC for PCT was found to be 17.3 mg/g. Thermodynamic analysis suggested endothermic, favorable, and spontaneous adsorption; with low enthalpy values (ΔH° = 8.099 kJ/mol), supporting physisorption. The DLPNO-CCDT(T)/6-311G(d,p) calculation method yielded the most reliable adsorption energy (E ads) and Gibbs free energy (Δ G ads) values between PCT and functional groups on the carbon surface, indicating strong interactions between the acid phosphate group of AC and the acetamide fragment of PCT (Δ G ads = −7.60 kcal/mol), and strong interactions between the ketone groups and lactone cycles with the hydroxyl (ΔG ads = −3.40 kcal/mol), and acetamide (ΔG ads = −1.91 kcal/mol) groups of PCT, respectively. The obtained results indicated, first, that the use of activated carbon from waste is an effective alternative adsorbent for the treatment of wastewater containing pharmaceutical compounds. Second, the application of theoretical computational methods in quantum chemistry provides a thorough understanding of the mechanism of the absorption of PCT at the carbon surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sulphuric acid recovers phosphorus from wastewater-microalgae derived biochar. • Metals like Fe, Ca, and Mg are remained in the biochar materials. • Metal-containing and S-doped biochars show strong electrochemical performance. • Acid leaching for biochar can provide carbon-negative energy storage solution. This study proposes a strategy for phosphorus recovery from algae biomass while simultaneously enhancing the electrochemical capacitance of resulting biochar in supercapacitor applications. Use of sulphuric acid leaching process on both wastewater microalgae and seaweed biochar demonstrated high phosphorus recovery rates, ranging from 93.4% to 95.4%, while at the same time retaining 52.7% to 58.6% of Fe content in the biochars. By modifying the sequential order of leaching (L) and physical activation (A) as LA and AL, the strategy allows for the optimisation of phosphorus recovery and the electrochemical properties of activated biochars. During the LA process, a more porous structure formed and more S-containing functional groups occurred compared to AL which explained the higher specific capacitance (486.3F g−1 at a current density of 1 A g−1) of wastewater microalgae biocarbon with the LA process. Consequently, the life cycle assessment of this strategy revealed a significant global warming reduction potential of 1.34–2.94 tonnes of CO 2 -eq/yr for each tonne of biochar produced. This indicates that sulphuric acid-assisted biochar production could be a sustainable strategy for waste management and carbon sequestration, while simultaneously generating economic profits from valorised carbon material for energy storage applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn/Al, Co/Al, Mg/Al and Ca/Al − combination of metals at the molar ratio 3/1 in hydrotalcite. • pH 6, time 360 min., temperature 333 K allowed to obtain the highest q t values. • The best match to Elovich and Temkin models suggesting chemisorption. • Ca/Al-LDH@BC the best cerium removal compared with other composites. • Process involves complexation, ion exchange, precipitation and electrostatic interactions. The innovative LDH@BC composites containing combination of metals: Zn/Al, Co/Al, Mg/Al, Ca/Al at the molar ratio 3/1 were synthesized using the co-precipitation method at constant pH. The composites were applied to remove Ce(III) ions from aqueous solutions. Batch experiments were conducted for determination of influence of solution pH, phase contact time, solution concentration and temperature. The kinetic and isotherm parameters were found using the non-linear regression method. As follows from the thermodynamic tests LDH@BC are more effective removal of Ce(III) ions at higher temperature and the sorption process is unforced and spontaneous. The leaching studies proved that 1 mol/L nitric acid is the best desorbing agent for Ce(III) ions deposited on the sorbent surface. Additionally, the composites were investigated applying the XRD and BET analyses (before sorption) as well as the ATR-FTIR, SEM-EDX, XPS methods (before and after the Ce(III) ions sorption). In summary, the introduction of hydrotalcite composed of Zn/Al, Co/Al, Mg/Al, Ca/Al as modifiers of biochar surface produced a potentially more cost-effective, and non-toxic cerium adsorbent for waters and wastewaters treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Organic solid waste-supported nanomaterial was applied to mediate toxic chemicals looping in rice. • Nanoscale Fe-(oxyhydr)oxide and LDH components from FLBC determined As and Cd fate. • FLBC application promoted the amorphous conversion of Fe-oxides on Fe plaques. • Nano-LDH bioassembly was firstly reported to influence As and Cd species in root. • FLBC amendment preferentially accumulated DMA and Cd in rice due to LDH introduction. The impact of organic solid waste-supported nanomaterial application on the biogeochemical looping of arsenic (As) and cadmium (Cd) in rhizosphere-root system of rice remains unclear. This study investigated the biochar-supported Fe-(oxyhydr)oxide and layered double hydroxide (FLBC) to modify As and Cd species and their accumulation in rice rhizosphere system under all life-cycle. The results demonstrated that total As and Cd in porewater and rice tissues decreased by > 70 % following 1 wt% FLBC application, close to national standards in grain. Inorganic As levels significantly decreased in roots and grains under FLBC application, resulting in the preferential accumulation of organic As like dimethylarsenate. FLBC amendment substantially increased the Fe plaques on root surfaces due to a rise in Fe(II) sink influenced by Fe(III)-reducing bacteria, and then promoted the conversion of crystalline-like FeO x to an amorphous-like structure on Fe plaque through X-ray diffraction and transmission electron microscope technologies (TEM), eventually reducing the As and Cd availabilities. The ultrastructural characterization, employing TEM equipped EDS spectrometer, revealed the bioassembly of nanoscale layered double hydroxide for the first time within the vacuoles of xylem cells in the root apex under FLBC amendment. This process allowed the transformation of As and Cd species from metastable Fe–Al oxides-bound compounds to stable complexations of cysteine-bound As(V)/Cd and Cd(OH) 2 within the intracellular spaces, as demonstrated by X-ray absorption near fine structure spectrum. In short, FLBC hindered the transformation and accumulation of As and Cd species in the rhizosphere-root system, providing a fresh perspective on organic solid waste-supported nanomaterials for ensuring safe crop production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel mono- (La) and bi-metal (CeLa) biochars were synthesised from conifer brash. • High adsorption capacities were detected (78 mg/g) in eutrophic lake water. • The governing adsorption mechanism was through ligand exchange. • La carbonate was the major ligand for exchange with phosphate on the surface. • Low toxicity response with marginal inhibition (<5%) was noted with Lepidium sativum. Phosphorus as a diminishing finite resource, yet is an essential element for the growth of biota. However, elevated concentrations in water can imbalance ecosystems and cause eutrophication. To address both problems, two highly efficient biochars, namely La-OB and CeLa-OB were synthesised by lanthanum and cerium doping. The performance of La-OB and CeLa-OB were evaluated in both batch and dynamic regimes with synthetic phosphate (PO 4 3--P) solutions and eutrophic lake water. PO 4 3--P adsorption mechanisms were investigated in terms of pH, kinetics, isotherms, activation energy, thermodynamics and using in-depth characterisation (XPS, FTIR, XRD, BET, pH pzc and SEM-EDX). The feasibility of using such biochar in 'real life' situations was studied with column filtration of lake water with low and high PO 4 3--P concentrations. Reusability/desorption and toxicity in the water environment was also considered. The mechanistic study showed that both biochars predominantly had inner-sphere complexes with La and Ce ligands (as a monolayer), while outer-sphere complexation was less common. The exothermic adsorption process followed the Elovich kinetic and Langmuir isotherm models, with a maximum adsorption capacity of 112 mg/g for La-OB and 40 mg/g for CeLa-OB. In column filtration trials the adsorption capacity reached 78 mg/g, while low metal leaching (0.08 mg/L) and low toxicity to Lepidium sativum germination were detected. The results indicated that these biochars, especially La-OB, could be used in circular economy-based water treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enhanced hydrophobicity of Janus structured photothermal conversion materials via impregnating silane solution. • Utilization of agricultural and forestry waste significantly promotes the sustainability of Janus materials. • Innovative portable air water intake device that can obtain water from the atmosphere. • A portable air water intake device produces clean water with 1.74 L m−2 day−1 fulfill an individual requirement. The utilization of photothermal conversion materials to enhance the desorption performance of hygroscopic salt solutions through interfacial photothermal effects presents a promising approach for the continuous extraction of water from the atmosphere. To improve the desorption efficiency of hygroscopic salt solutions, the objective of this research is to employ agricultural and forestry residues, such as corn straw, in conjunction with polyurethane sponges, for the production of an innovative Janus structure carbonized biomass photothermal conversion material. Compared to single-layer structured photothermal conversion materials, the pure water evaporation rate increased from 2.42 kg m-2 h-1 to 3.20 kg m-2 h-1 when utilizing the Janus structured photothermal conversion material. Remarkably, this material demonstrates outstanding resistance to salt, allowing it to endure 8 h evaporation cycles with 30 wt% NaCl without salt crystallization. Therefore, it is well-suited for the continuous desorption of liquid hygroscopic agents. Moreover, the portable air–water extraction device, which incorporates Janus structural photothermal conversion material to enhance the performance of 30 % LiCl, has been shown to effectively extract water in practical settings. It achieves a water intake rate of 1.74 L m-2 d-1 at 50 % humidity. This approach is distinguished by its simplicity, cost-effectiveness, and efficient utilization of solar energy resources, providing a promising solution to mitigate the shortage of fresh water resources. [ABSTRACT FROM AUTHOR]

Biochar supported sulfidized nanoscale zerovalent iron (S-nZVI-BC) has shown great potential for environmental remediation. However, the feasibility of S-nZVI-BC for the immobilization of cadmium (Cd) in sediment and concomitant ecological consequences remains unclear. Herein, this study systematically investigated the effectiveness, environmental impacts and mechanisms of S-nZVI-BC for remediating of Cd polluted sediment and evaluated the contribution of iron reducing bacteria (IRB) for Cd immobilization. The Cd immobilization by S-nZVI-BC was superior to nZVI, BC, nZVI-BC and S-nZVI, with a maximum residual percentage increasing by 56.93%, the leachability decreasing by 94.48% and the availability reducing by 88.25%. The sediment pH, Eh, dissolved organic carbon (DOC) and leaching Fe2+ played a vital role in Cd immobilization. Three enzyme activities (urease, sucrase, and cellulase) were enhanced after S-nZVI-BC treatment, suggesting an improvement in sediment quality. However, catalase activity decreased, possibly because of the influence of Fe2+ from S-nZVI-BC. The microbial community structure was changed and the abundance of some IRB was improved by S-nZVI-BC. The RT-qPCR results indicated that the absolute abundance of Clostridium (a typical IRB) increased by 1.66 log, which enhanced the iron cycle and Cd re-immobilization. The characterization results confirmed that Cd immobilization by S-nZVI-BC was achieved via adsorption, surface adsorption-complexation and precipitation. Therefore, S-nZVI-BC showed excellent Cd immobilization performance and long-term stability, being well adapted for the treatment of Cd polluted sediment. [Display omitted] • S-nZVI-BC maintained high efficiency for Cd immobilization even after 90 days. • The sediment properties played a vital role in Cd immobilization by S-nZVI-BC. • S-nZVI-BC enhanced the enzymatic activities (urease, sucrase and cellulase). • The iron reducing bacteria (Clostridium) promoted Cd immobilization by S-nZVI-BC. • Adsorption, complexation and precipitation dominated Cd immobilization. [ABSTRACT FROM AUTHOR]

Every year, billions of tons of iron-rich waste are generated globally, presenting a valuable resource for synthesizing iron-based catalysts. In this study, we synthesized iron oxide-biochar (Iron Oxide@Biochar) nanocomposites by ball milling a combination of tea leaves and iron-rich waste. These nanocomposites were found to be highly efficient activators of peroxymonosulfate (PMS) for degrading tetracycline (TC). Particularly, biochar-encapsulated disposable instant hot packs (DHP/BC) achieved a TC removal efficiency of 94.7% under optimal conditions, exhibiting excellent stability and strong anti-interference capabilities. Our analysis revealed that TC degradation predominantly occurred via a non-radical pathway involving singlet oxygen (1O 2) and electron transfer, with free radicals (·OH and SO 4 ·-) playing a secondary role. This research not only offers an economical and efficient solution for recycling solid waste and reusing natural biochar but also introduces a sustainable and environmentally friendly method for preparing catalysts for pollutant degradation, thus achieving the dual goals of "resource recycling" and "treating waste with waste." [Display omitted] [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]

Pyrogenic carbon capture and storage (PyCCS) based on biochar is considered a negative emission technology (NET) aimed at mitigating climate change, with the potential to reduce CO 2 by 0.3–2 gigaton/yr at the cost of $30–120/ton-CO 2. The annual biochar production needs a substantial scaling up of the current production rates (i.e., >150 million tons by 2050) to meet the above demand. However, current biochar production predominantly relies on a small-scale operation, which generally leads to high operational costs and limited control of the biochar properties. This work presents the operation of a state-of-the-art 1 ton/d pilot-scale Flexible Counter Flow Multi-Baffle (F-COMB) pyrolyzer designed for continuous biochar production, which is a prototype reactor for the scale-up. The F-COMB utilizes counter-flow and vortex mixing in a multi-baffle column structure to enable efficient contact of feedstock with hot gas. It boasts high energy efficiency and economic feasibility through a short residence time, reduced gas flow rate, and simple structure. It produces wood pellet biochar with accurate control of the reaction conditions such as temperature, retention time, hot gas flow rate, and feedstock loading. Moreover, continuous biochar production is done successfully with three flexible baffles configuration, demonstrating the significant potential for the scale-up. • Flexible Counter Flow Multi-Baffle (F-COMB) reactor is designed for pyrolysis. • F-COMB provides high energy efficiency via efficient contact of feedstock & hot gas. • Vortex mixing induced by multiple baffles gives the efficient contact. • Biochar production using a F-COMB was demonstrated at 1 ton/day scale successfully. • Continuous biochar production shows significant potential for the F-COMB scale-up. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stable bimetallic-vinyl complex with unique structure is formed on oxidized biochar. • Characterization and DFT calculation results verify the rationality of the structure. • Loading amount of Pt in catalyst can by reduced by about 32% to efficiently save cost. • Metal particles on prepared catalyst surface are evenly dispersed with minimum size. • Catalytic performances for hydrosilylation of alkene with silane is kept and improved. A bimetallic PtNi-vinyl complex as catalytic active center was created on modified rice straw biochar by introducing an appropriate amount of cheap Ni component as a catalytic promoter. The constructed bimetallic catalyst (PtNi-VTES-RSOC) was used to catalyze hydrosilylation of terminal alkenes with tertiary silanes to produce alkylsilanes with high commercial application value. The experimental results proved that the conversion of 1-octene 96.5 % and selectivity for target product 97.1 % were obtained in hydrosilylation of 1-octene with triethoxysilane catalyzed by PtNi-VTES-RSOC with mass ratio of Pt/Ni = 1.5:1 (molar ratio of Pt/Ni≈1:2) under mild conditions (atmospheric pressure, solvent-free, 50 ℃ and 3 h). It also possessed higher catalytic ability and regioselectivity for hydrosilyation of long-chain alkenes (1-octadecene) with tertiary silanes compared to the counterpart monometallic catalysts. The characterization and theoretical calculation results demonstrated that the introduced suitable amount of Ni(II) could affect the structure of original Pt(II)-vinyl complexes and form a stable and unique bimetallic vinyl coordination microstructure by using a shared vinyl group, thereby affecting morphology, structure, and catalytic performance of the as-prepared bimetallic catalyst with mass ratio of Pt/Ni = 1.5:1. Changing the introduction order and introducing excessive or insufficient of Ni(II) would both disrupt the formation of this special structure and affect the catalytic performance. Additionally, the formed stable complex structure with vinyl groups could well maintain the catalytic stability. The study results exposed that the as-prepared bimetallic catalyst would possess a great industrial application potential in the hydrosilylation of alkenes by efficiently increasing the product quality and reducing operation cost. [ABSTRACT FROM AUTHOR]

Biochar is an environmentally friendly material with great potential for carbon capture and storage. As the first of its kind, waste biomass-derived biochar was utilized to convert CO 2 into fuel in solar. Herein, among four representatives herbaceous, woody, sludge, and manure wastes, the pine sawdust-derived biochar produced the highest CO assisted by higher CO 2 adsorption, more than 10 times higher than that of graphene and activated carbon. The function groups of carbonyl and carboxyl on biochar controlled the CO 2 capture and solar conversion by decreasing adsorption and activation energies of CO 2 molecules. The biochar performed even better for 15% CO 2 /N 2 atmosphere, a typical CO 2 concentration in the flue gas, demonstrating its promising potential in waste gas resource utilization. The life-cycle assessment indicates that feedstock with more cellulose and lignin provide better environmental and economic benefits. The work highlights a sustainability pathway for waste biomass-derived biochar in CO 2 -to-fuel under ambient conditions. [Display omitted] • Waste biomass-derived biochar show excellent adsorption-photocatalytic CO 2. • Biochar have promising applications in utilization CO 2 in the industrial flue gas. • Carboxyl and carbonyl functional groups of biochar are the key to CO 2 conversion. • Waste biomass with more cellulose and lignin favor higher environmental benefits. [ABSTRACT FROM AUTHOR]

Rational reuse of municipal sludge to produce electro-Fenton electrode can not only save resources, but also produce superior peroxide and degradation pollutants simultaneously. Herein, a novel electro-Fenton electrode derived from sludge biochar loaded on Ni foam (SBC@Ni) was constructed via high temperature pyrolysis and chemical coating for efficient H 2 O 2 evolution and pollutant degradation. Systematic experiments and density functional theory calculations (DFT calculation) explained that the production of graphite C and graphite N during high-temperature pyrolysis of municipal sludge can greatly enhance the oxygen reduction reaction of SBC@Ni electrode and promote the evolution of H 2 O 2. And the hybrid heterojunctions, such as FeP, also played a key role in electrocatalytic processes. Notably, the electrode still exhibited excellent performance after 1000 linear scans and 12 h of continuous current stimulation, which demonstrated the excellent stability of the electrode. Moreover, SBC@Ni electrode can not only effectively oxidize 4-chlorophenol through the electro-Fenton effect, but also fully mineralize organic matter, indicating promising environmental application. The free radical quenching experiment also revealed that the ·OH is the main active species for 4-CP degradation in SBC@Ni electro-Fenton system. [Display omitted] • The Ni biochar electrode effectively promoted the electro-Fenton reaction. • High-temperature pyrolysis contributed to the formation of Graphite-C/N. • DFT proved that Graphite-C/N can accelerate the 2e– ORR reaction. • Sludge biochar electrodes can efficiently and stably degrade and mineralize 4-CP. [ABSTRACT FROM AUTHOR]

Fe and N co-doped walnut shell biochar (Fe,N-BC) was prepared through a one-pot pyrolysis procedure by using walnut shells as feedstocks, melamine as the N source, and iron (III) chloride as the Fe source. Moreover, pristine biochar (BC), nitrogen-doped biochar (N-BC), and α-Fe 2 O 3 -BC were synthesized as controls. All the prepared materials were characterized by different techniques and were used for the activation of peroxymonosulfate (PMS) for the degradation of sulfamethoxazole (SMX). A very high degradation rate for SMX (10 mg/L) was achieved with Fe,N-BC/PMS (0.5 min−1), which was higher than those for BC/PMS (0.026 min−1), N-BC/PMS (0.038 min−1), and α-Fe 2 O 3 -BC/PMS (0.33 min−1) under the same conditions. This is mainly due to the formation of Fe 3 C and iron oxides, which are very reactive for the activation of PMS. In the next step, Fe,N-BC was employed for the formation of a composite membrane structure by a liquid-induced phase inversion process. The synthesized ultrafiltration membrane not only exhibited high separation performance for humic acid sodium salt (HA, 98%) but also exhibited improved self-cleaning properties when applied for rhodamine B (RhB) filtration combined with a PMS solution cleaning procedure. Scavenging experiments revealed that 1O 2 was the predominant species responsible for the degradation of SMX. The transformation products of SMX and possible degradation pathways were also identified. Furthermore, the toxicity assessment revealed that the overall toxicity of the intermediate was lower than that of SMX. [Display omitted] • Fe and N co-doped biochar demonstrated an excellent degradation efficiency for SMX. • The synergistic effects of Fe and N co-doping on biochar properties were discussed. • 1O 2 are the main active species for the degradation of SMX in the Fe,N-BC/PMS system. • The separation and self-cleaning performances of the Fe,N-BC membrane were evaluated. [ABSTRACT FROM AUTHOR]

Designing efficient catalyst for peroxymonosulfate (PMS) activation is beneficial for eliminating the adverse effects of sulfamethoxazole (SMX) on human health. A novel boron (B) and nitrogen (N) co-doped sludge biochar (BNSBC) was synthesized by one-pot hydrothermal activation, and its remarkable PMS activation performance facilitated the rapid elimination of SMX from water. The degradation rate of SMX by BNSBC/PMS system could reach 92.1% within 60 min ([SMX] 0 = 10 mg/L, [BNSBC] 0 = 0.4 g/L, [PMS] 0 = 1 mM). B and N exhibited the synergistic enhancement effects on the physico-chemical characteristics of SBC, and abundant pores, defects, C O, -O-B-O-, graphitic-N and pyridinic N were confirmed as the main active sites of BNSBC for PMS activation. Characterization, quenching, electron paramagnetic resonance (EPR) and electrochemical tests proved that non-radicals of surface-bound, 1O 2 and electron transfer were the main contributors to SMX degradation. The high anti-interference of BNSBC/PMS system to pH range, co-existing inorganic anions and organic matter guaranteed its outstanding purification performance for SMX in diverse environmental waters. Four potential degradation pathways of SMX in BNSBC/PMS system were proposed by its intermediates identification and density functional theory (DFT) calculation, and pathway Ⅳ was the main one. The toxicity levels of its intermediates were lower than that of SMX regardless of chronic and acute toxicity. Also, BNSBC/PMS system exhibited the board-spectrum removal performance for other typical antibiotics (e.g., sulfadiazine (SDZ), sulfamethoxypyridazine (SMP), ciprofloxacin (CIP), tetracycline (TC)). BNSBC/PMS has great application potential for eliminating diverse antibiotics in actual wastewater due to its high tolerance to complex environmental conditions and outstanding detoxification ability, also it offers a harmless disposal approach for sludge. [Display omitted] [ABSTRACT FROM AUTHOR]

The current study aims to develop an intelligent system incorporating various mitigation technologies. In this investigation, three technologies; Direct Air Capture (DAC), Bioenergy with Carbon Capture and Storage (BECCS), and Biochar production from pyrolysis are evaluated for their capacity to mitigate one million tonnes of CO 2. Process models are developed for each method, followed by techno-economic analyses and optimization to derive the most effective solution. The holistic approach considers objectives such as net energy gain, minimized water usage, and product sales. The results highlight BECCS as the most promising in terms of net energy gain, offering approximately 18.08 GJ, closely followed by Biochar, which offers about 15.08 GJ per 1 tonne of captured CO 2. Biochar stands out for its lower water consumption of 2.3 m³ compared to BECCS water consumption of 3.03 m³, while DAC exhibits higher water usage and demands extensive energy consumption of 11.95 GJ per 1 tonne of captured CO 2. Economic analysis reflects these scenarios, with Biochar, BECCS, and DAC presenting product sales of $756 million, $233 million, and $60 million, respectively. The optimization process revealed about 22 potential solutions based on energy, waste usage, and sales nexus. It suggests a system comprising 53% Biochar and 47% BECCS, considering the highest net energy gain, minimizedwater usage and cost and elevated technology maturity. [Display omitted] • Three key technologies; DAC, BECCS, and biochar are evaluated for net emissions. • DAC appears to involve a more extensive use of water and energy. • BECCS produced a higher net energy gain compared to other processes. • In economic parameters, biochar and BECCS have higher product selling values. • The optimal hybrid system (BECCS 47% and biochar 53%) for mitigating 1 Mt of CO 2. [ABSTRACT FROM AUTHOR]

• Phosphoric acid-modified biochar-supported nZVI is prepared. • BPA degradation rate reaches to 92.66 % within 60 min under optimized conditions. • The •OH, •SO 4 −, •O 2 −, and 1O 2 are involved in the PMS-based degradation of BPA. • The 1O 2 plays a prominent role in the degradation of BPA over PBC/nZVI/PMS system. • BPA is degraded through •OH-induced oxidation and SO 4 •−-induced hydroxylation. The degradation efficiency of bisphenol A (BPA) using sulfate radical-based advanced oxidation processes still requires further improvement. Herein, we prepared phosphoric acid-modified biochar-supported nZVI (PBC/nZVI) through liquid-phase reduction. Under optimized conditions, including a PBC/nZVI dosage of 1.2 g/L, pH 9.0, and PMS concentration of 2.0 mmol/L, the BPA degradation rate reached up to 92.66 % within 60 min with the mineralization rate of 45.5 %. The presence of Cl−, HCO 3 − and CO 3 2− promoted the degradation of BPA, while NO 3 − had minimal effect. Conversely, H 2 PO 4 − and humic acid exhibited varying degrees of inhibition. The degradation of BPA involved four reactive oxygen species (•OH, SO 4 •−, O 2 •−, and 1O 2), with 1O 2 playing a prominent role. The pathways of •OH-induced oxidation and SO 4 •−-induced hydroxylation were identified as the mechanisms through which BPA was degraded. These findings highlighted the potential of PBC/nZVI as a rapid and efficient material for BPA degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simple composite method to encapsulate biochar in a gel network. • CrO 4 2− as a bridge for synergistic adsorption of dyes. • Column adsorption simulation to explore the potential of adsorbents. • High cyclic stability of the adsorbent. With the continuous development of industrialization, dyes in industrial wastewater have become a serious environmental issue. To address this environmental issue, a biochar-based composite hydrogel (PAS/aBC-CD) was designed. The use of a simple composite method effectively resolves the challenge of biochar recovery. Furthermore, the modified adsorbent exhibits remarkably high adsorption capacities for all three dyes (MB: 1494 mg/g, MG: 1182 mg/g, and NR: 1031.6 mg/g). It is noteworthy that binary co-adsorption experiments have demonstrated that CrO 4 2− can act as a bridging agent to enhance the adsorption of dyes by the adsorbent. Systematic adsorption–desorption experiments have demonstrated the outstanding recyclability of PAS/aBC-CD, maintaining 98 % of its adsorption capacity after 5 cycles. Additionally, its industrial application potential was demonstrated through column adsorption experiments. In conclusion, this study utilized a simple composite method to produce an adsorbent with high adsorption performance and industrial application potential. [ABSTRACT FROM AUTHOR]

The seasonally shed bark of London Plane tree is an ideal source for biochar due to its high lignin content. Microplastics derived from plastic wastes has become a hot topic due to its potential threats to ecosystems. The aim of this work is to convert the shed bark into efficient London Plane bark biochar (LBC) adsorbents and investigate its application in microplastics adsorption. The effects of pyrolysis temperature on LBC structure, surface properties and microplastic adsorption were investigated and the best adsorption performance of 60.05 mg/L was found at the 550 °C-pyrolyzed LBC. The wet sieve-weighing method was applied to assess the adsorption effect of LBC and verified with thermogravimetric analysis. The adsorption of polystyrene (PS) particles on LBC was in accordance with the Sips isothermal model and the second-order-kinetics model. The robustness of LBCs and the adsorption mechanism were investigated. With the analysis from pore size distribution, SEM images, FTIR and XPS spectra, physical trapping, surface complexation, hydrogen bonding and π-π interaction all play key roles in the adsorption of PS onto the LBC surface. This study not only provides a new approach for the removal of microplastics, but also offers a broad perspective on the treatment of biomass waste. [Display omitted] • Biowaste was pyrolyzed into an efficient biochar adsorbent for microplastic and showed significant removal effect. • The effects of pyrolysis temperature on biochar structure, surface properties and microplastic adsorption were investigated. • The adsorption mechnism is investigated to provide ideas for the efficient microplastic adsorbents design. • Wet sieve-weighing method was creatively adopted to evaluate the adsorption capacity and proved to be highly operational and accurate. [ABSTRACT FROM AUTHOR]

In recent years, Spartina alterniflora as an invasive species has seriously threatened the native coastal ecosystem of China. There is a lack of effective management and utilization methods towards Spartina alterniflora at present. To realize the ecological remediation and resource utilization of Spartina alterniflora , the functional biochar (BC) materials were successfully prepared using Spartina alterniflora as the substrates via the high temperature calcination method, which were utilized for efficient removal of antibiotics. The biochar was further activated by ZnCl 2 (ZnBC) and optimized under different calcination temperatures and ZnCl 2 dosages to improve the adsorption ability. Among these biochar materials, the ZnCl 2 -activated biochar obtained under the mass ratio of Spartina alterniflora to ZnCl 2 of 1:5 and calcination temperature of 600 °C (ZnBC-600) exhibited the strongest adsorption performance towards sulfadiazine (SDZ) and ciprofloxacin (CIP), which can be attributed to the larger specific surface area, richer pore structure and more abundant surface oxygen-containing functional groups. Additionally, the adsorption kinetics and isotherms demonstrated that the adsorption of both SDZ and CIP onto ZnBC-600 (1:5) followed the pseudo-second-order kinetic model and Freundlich model. At the same time, the performances of Spartina alterniflora biochar derived from different biomass were compared under the condition of activation with ZnCl 2 , presenting the superior performance of ZnCl 2 activated Spartina alterniflora biochar. Moreover, the adsorption mechanism of ZnBC-600 (1:5) was proposed, illustrating the crucial roles of effects of electrostatic attraction, pore filling, oxygen-containing groups complexation, π-π stacking and hydrogen bonding in the adsorption of antibiotics. Above all, this study not only provides a feasible strategy for the preparation of functional biochar derived from Spartina alterniflora for removing organic pollutants, but also opens up a new pathway for resource utilization of Spartina alterniflora. [Display omitted] [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]

Torrefaction is an efficient pretreatment technology for large-scale and high-value utilization of biomass fuel. This study aims to enhance the understanding of the thermochemical conversion of torrefied biomass by delineating the role of potassium and torrefaction on primary/secondary charring reactions during pyrolysis of torrefied cellulose. Celluloses with varying potassium loading levels were torrefied at temperatures ranging from 200 to 320 °C and subsequently pyrolyzed at 1000 °C. Two contrasting pyrolysis conditions, i.e., limiting and enhancing transport resistance, were employed to tune the occurrence of secondary reactions, thereby determining the role of torrefaction and potassium on primary and secondary charring reactions. Potassium content, torrefaction severity, and pyrolysis conditions both profoundly affects char formation during pyrolysis of torrefied cellulose, resulting in a wide range of pyrolysis char yields from 1.95 wt% to 64.35 wt%. The structural changes induced by torrefaction, including the depolymerization of the carbohydrate structure and the formation of crosslinking structures, promote the char formation. Potassium enhances the char formation of torrefied cellulose in two ways: i) by catalyzing the transformation of the carbohydrate structure into the crosslinking structure during torrefaction, and ii) by catalyzing the charring reactions of both the carbohydrate and the crosslinking structures during pyrolysis. Raman spectral analysis of the char carbon structure indicates that increased potassium loading level and torrefaction severity enlarge the aromatic system of the char. The findings highlight the potential of optimizing biomass pyrolysis through controlled torrefaction and potassium, paving the way for more efficient biofuel production and high-quality biochar applications. • The role of potassium and torrefaction on char formation during pyrolysis is investigated. • A wide range of pyrolysis char yields from 1.95 to 64.35 wt% is reported. • Torrefied celluloses pretreated at different temperature exhibit different charring behavior. • Potassium can promote char formation by altering structure of torrefied cellulose. • A linear correlation is established between char yield and char carbon structure. [ABSTRACT FROM AUTHOR]

Herein, we report the development of a highly efficient activated porous acid catalyst using Psidium guajava (guava) leaves as the precursor. The synthesis involved chemical activation with ZnCl 2 and sulfonation with 4-benzenediazonium sulfonate, resulting in the AC-X-PhSO 3 H catalyst, optimized by varying ZnCl 2 ratios (X = 1, 2, 3). Comparative characterization using BET, SEM, XRD, FT-IR, and TGA revealed that AC-2-PhSO 3 H, pyrolyzed at 500 °C, exhibited exceptional efficiency with a maximum surface area of 492.97 m²/g and a sulfur density of 4.23 wt%. Using AC-2-PhSO 3 H as the catalyst, we achieved a remarkable Jatropha curcas oil (JCO) conversion (98.3 ± 0.3 %) to biodiesel under optimized reaction conditions (20:1 methanol to oil molar ratio, 10 wt% catalyst loading, 100 °C, 50 min) and FAME content of 98.04 %, as confirmed by ¹H NMR spectroscopy. The estimated cost of biodiesel production was $0.87 per litre, largely due to the notable reusability of the catalyst (82.9 ± 0.2 % JCO conversion in the 6th run) without additional treatments, indicating significant commercial applicability and enhanced stability. [Display omitted] • Highly efficient Psidium guajava leaves-derived acid catalyst for biodiesel synthesis. • Optimal AC-2-PhSO 3 H catalyst with high porosity and S BET of 492.97 m²/g. • Microwave-assisted transesterification exhibits high JCO conversion (98.3 ± 0.3 %). • Notable reusability over six cycles (82.9 ± 0.2 % JCO conversion) validating high stability. • Life cycle cost analysis estimated biodiesel production cost to be $0.87 L–1. [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]