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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]

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]

In this study, we report an efficient, stable, and renewable N, P co-doped coffee biochar-based catalyst loaded with highly dispersed Ni-N x species (Ni/NPCB-600), and it was successfully applied to the aqueous-phase chemoselective reduction or reductive amination of diverse nitroarenes (Yield up to >91%). Experimental and characterization studies revealed that N, P co-doping have a synergistic effect on improving the catalytic performance of Ni/NPCB-600. The textural properties of Ni/NPCB-600 are enhanced after doping of P, which can facilitate mass transfer and expose more accessible active sites in the reaction. The doping of N could induce the formation of Ni-N x sites and enhance the basicity of the Ni/NPCB-600 catalyst, which can promote the adsorption and activation of formic acid and nitroarenes, respectively. This is the first example of N, P co-doped coffee biochar-based catalyst for nitroarenes reduction or reductive amination, and reveals its potential industrial application prospects. [Display omitted] • Ni-N x supported on N, P co-doped coffee biochar was fabricated for the first time. • N, P co-doping could promote the catalytic performance of Ni/NPCB-600. • Using formic acid as a green and renewable source of hydrogen. • Ni/NPCB-600 exhibits good applicability to various nitroarenes. • High activity and chemoselective retained over 10 recycles. [ABSTRACT FROM AUTHOR]

The rapid emergence of unique types of pollutants is of worldwide concern owing to their deleterious effects on living beings. Mitigating pollution in the way of sustainability is the need of the hour to protect the existing environment from degradation. In this regard, eco-friendly biochar was prepared from the intact plant of Eichhornia crassipes (water hyacinth) without neglecting the roots, stems, leaves, and flowers and assessed for its ammonium removal efficiency in the study. Twelve biochars of two categories, viz., treated and normal, were produced under two different pyrolysis temperatures of 300 °C and 500 °C and three residence times of 30, 45, and 60 min. The adsorption experiments were conducted as batch studies in triplicate to examine the impacts of multiple adsorption-inducing factors in biochar. The maximum ammonium removal efficiency of about 83% was shown by the alkali-activated biochar produced at a higher temperature of 500 °C with a longer residence time of 60 min. The biochar showing higher ammonium adsorption was characterized by Scanning Electron Microscopy and Fourier Transform Infra-Red spectroscopy, which revealed the increased number of pores and the presence of C–O, OH, and C O groups that altogether aided the adsorption process. The kinetic study conducted with contact times of 30, 60, and 90 min showed that the linear regression values were >0.999 for the pseudo-second-order kinetic model, which revealed that the ammonia sorption of Eichhornia biochars followed a second-order mechanism of chemisorption. Synthesized biochar has shown significant efficacy in ammonia adsorption, making it worthwhile in applications where ammonia removal is necessary, particularly in wastewater treatment besides agriculture and air purification. [Display omitted] [ABSTRACT FROM AUTHOR]

The safe disposal of sewage sludge (SS) and food waste digestate residues (DR) is a tough issue considering the difficulty of dewatering and the environmental risks from heavy metals and pathogens. This study combined hydrothermal pretreatment (HP), anaerobic digestion (AD), and pyrolysis to synergistically dispose of SS and DR to enhance dewaterability, recover energy, and prepare biochar with heavy metal immobilization. The results showed that the solid contents of centrifuged cakes increased after HP at 180 °C of SS with the addition of 25% and 50% mass fractions of DR. The centrate from co-HP had a high chemical oxygen demand (COD) and was further treated by AD at 37 °C, producing 193.75 and 210.39 mL/g COD input (25 °C and 1 atm) of cumulative CH 4 under the addition of 50% and 75% mass fractions of DR, respectively. The methanogenic types in AD converted from hydrogen utilization to acetic acid utilization with increasing DR ratio. Zn, Cu, Ni, and Pb were primarily left in the biochar after 50% mass fraction of DR was mixed in the HP combined with pyrolysis at 700 °C; the chemical fractionation of Zn, Cu, Cr, and Pb in the biochar increased to over 85% of the residual fractions, resulting in the lowest potential ecological risk index (15.22, low risk). The CH 4 produced from the AD of the co-HP centrate (50: 50, w / w) can supply heat for the HP process, reducing the energy input by 89%. This co-disposal strategy can effectively recover carbon resources from solid wastes to reduce carbon emissions. • HP, AD coupled with pyrolysis were used for synergistic treatment of SS and DR. • The dewaterability of SS improved after HP with the addition of DR. • The generated CH 4 can supply heat for the HP, reducing the energy input by 89%. • The biochar had a low heavy metal risk after HP combined with pyrolysis. [ABSTRACT FROM AUTHOR]

Stormwater pollution is a key factor contributing to water quality degradation, posing substantial environmental and human health risks. Although stormwater retention ponds, also referred to as wet ponds, are commonly implemented to alleviate stormwater challenges by reducing peak flow and removing suspended solids, their effectiveness in removing heavy metals and nutrients is limited. This study evaluated the performance of floating treatment platforms (FTPs) featuring vetiver grass (Chrysopogon zizanioides), a non-invasive, nutrient- and metal-accumulating perennial grass, in removing heavy metals (Cu, Pb, and Zn) and nutrients (P and N) in stormwater retention ponds. Furthermore, the potential for utilizing the spent vetiver biomass for generating biochar and bioethanol was investigated. The study was conducted in a greenhouse setup under simulated wet and dry weather conditions using pond water collected from a retention pond in Stafford Township, New Jersey, USA. Two FTPs with vetiver (vegetated FTPs) were compared with two FTPs without vetiver (non-vegetated FTPs), which served as controls. Results showed that the removal of heavy metals and nutrients by the FTPs with vetiver was significantly higher (p < 0.05) than the FTPs without vetiver. Notably, vetiver showed resilience to stormwater pollutants and hydroponic conditions, displaying no visible stress symptoms. The biochar and bioethanol generated from the spent vetiver exhibited desirable yield and quality, without raising concerns regarding pollutant leaching, indicated by very low TCLP and SPLP concentrations. This study provides compelling evidence that the implementation of vetiver-based FTPs offers a cost-effective and environment-friendly solution for mitigating stormwater pollution in retention ponds. Furthermore, the utilization of vetiver biomass for biofuel and biochar production supports clean production and fostering circular economy efforts. [Display omitted] • Vetiver-based floating treatment platform (FTP) was designed to retrofit wet ponds. • Vetiver-based FTP significantly enhanced the removal of nutrients and metals. • Vetiver was resilient to stormwater pollutants and hydroponic conditions. • Biochar and bioethanol produced from spent vetiver had desirable yield and quality. [ABSTRACT FROM AUTHOR]

Recent research has found biochar to be a cost-effective adsorbent for removal of perfluoroalkyl substances in water. To promote cleaner production and sustainable waste management, this study explored the potential to produce activated biochars by co-pyrolyzing sawdust with iron-rich biosolids and polyaluminum sludge. The maximum capacity to adsorb perfluorooctanesulfonic acid (PFOS) reached 27.2 mg g−1 with biosolids-activated biochar and 19.2 mg g−1 with aluminum sludge-activated biochar, compared to 6.2 mg g−1 with sawdust biochar. The increased adsorption capacities were attributed to electrostatic interactions between the anionic PFOS and metal functionalities on the biochar surface. In contrast, hydrophobic interaction was the dominant adsorption mechanism of sawdust biochar. The presence of dissolved organic matter at 5–50 mg L−1 was found to inhibit adsorption of PFOS in water, while pH as low as 3.0 and sodium chloride concentrations up to 100 mM enhanced removal of PFOS by all the three adsorbents. In batch adsorption tests at environmentally relevant PFOS dosages and adsorbent dosage of 0.25 g L−1, the biosolids-sawdust biochar and Al sludge-sawdust biochar removed 71.4% and 66.9% of PFOS from drinking water and 77.9% and 87.9% of PFOS from filtrate of sludge digestate, respectively. The biosolids-sawdust biochar additionally removed Fe, although the Al sludge-sawdust biochar released Al into the alkaline drinking water and filtrate. Overall, this study proved co-pyrolyzing sawdust and Fe-rich biosolids to be an effective approach to activate sawdust biochar for enhanced removal of PFOS while recycling wastewater treatment residuals and sawdust. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, filamentous algae blooms and microplastics (MPs) pollution have become two major ecological and environmental problems in urban water systems. In order to solve these two problems at the same time, this study explored the loading capacity of MPs on fresh filamentous algae, and successfully synthesized magnetic filamentous algae biochar loading with Fe 3 O 4 by hydrothermal method, with the purpose of removing MPs from water. The magnetic filamentous algal biochar was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and so on. Experiments on adsorption kinetics, adsorption isotherms and optimum pH were carried out to explore the adsorption mechanism of MPs on magnetic filamentous algal biochar. The adsorption kinetics and adsorption isotherm models were evaluated, and the selection criterion for the appropriate model was determined by using the residual sum of squares (RSS) and Bayesian information criterion (BIC). Microscope images revealed that fresh filamentous algae could interact with MPs in the form of entanglement, adhesion and encapsulation. The average load of MPs in filamentous algae samples was 14.1 ± 5 items/g dry weight. The theoretical maximum adsorption capacities of polystyrene MPs (PS-MPs) by raw biochar (A500) and magnetic biochar with Fe 3 O 4 (M2A500) were 176.99 mg/g and 215.58 mg/g, respectively. The adsorbent materials gave better reusability because they could be reused up to five times. Overall, these findings have provided new insights into the use of filamentous algae for in situ remediation of fluvial MPs pollution, as well as feasible strategies for the recycling of algal waste. [Display omitted] • Removal effects of filamentous algae on MPs are investigated for the first time. • Growing filamentous algae can accumulate microplastics. • Biochar prepared from filamentous algal waste can effectively remove MPs. • Eco-friendly remediation approach is promising in reducing MP pollution. [ABSTRACT FROM AUTHOR]

Phosphorus (P) and Ammonium Nitrogen (N) are essential nutrients for plants and environmental stability. However, their excess in water causes eutrophication, damaging aquatic ecosystems. While adsorption is a promising solution, finding affordable and efficient adsorbents remains a challenge. In this study, magnesium (Mg), iron (Fe), and Mg/Fe doped biochars (BC) adsorbents were synthesized, and evaluated for adsorption of individual P and N and a P + N mixture from a solution and wastewater from a wastewater treatment plant. Compared to other adsorbents, Mg/BC showed excellent performance in adsorbing phosphorus (P) and ammonium nitrogen (N) from aqueous solutions. It demonstrated a large adsorption capacity of 64.65 mg/g and 62.50 mg/g from individual P and N solutions, and 30.3 mg/g and 27.67 mg/g from the P and N mixture solution, respectively. In addition, Mg/BC efficiently removed P and N from real-life wastewater. In the real wastewater, P and N removal efficiencies reached 88.30% and 59.36%, respectively. Kinetics analysis revealed that the pseudo-second-order model accurately described the adsorption of phosphorus (P) and ammonium nitrogen (N) in all solutions. The adsorbent followed the monolayer-Langmuir isotherm for N ions and the multilayer-Freundlich isotherm for P, indicating efficient adsorption processes. Thermodynamic experiments indicated that the adsorption of P and N was not only feasible but also occurred spontaneously in a natural manner. This study revealed that the strategic modification of biochar plays a crucial role in advancing effective wastewater treatment technologies designed for nutrient removal. [Display omitted] • Air calcined metal chloride adsorbents were devolved for P & N adsorption from wastewater. • Maximum adsorption P (64.65 mg/g) & N (62.50 mg/g) was found with Mg/BC adsorbent. • Efficiently simultaneous adsorption of P & N was achieved by Mg/BC adsorbent. • P and N adsorption mechanisms were studied. [ABSTRACT FROM AUTHOR]

Biochar has emerged as an efficacious green material for remediation of a wide spectrum of environmental pollutants. Biochar has excellent characteristics and can be used to reduce the bioavailability and leachability of emerging pollutants in soil through adsorption and other physico-chemical reactions. This paper systematically reviewed previous researches on application of biochar/engineered biochar for removal of soil contaminants, and underlying adsorption mechanism. Engineered biochar are derivatives of pristine biochar that are modified by various physico-chemical and biological procedures to improve their adsorption capacities for contaminants. This review will promote the possibility to expand the application of biochar for restoration of degraded lands in the industrial area or saline soil, and further increase the useable area. This review shows that application of biochar is a win-win strategy for recycling and utilization of waste biomass and environmental remediation. Application of biochar for remediation of contaminated soils may provide a new solution to the problem of soil pollution. However, these studies were performed mainly in a laboratory or a small scale, hence, further investigations are required to fill the research gaps and to check real-time applicability of engineered biochar on the industrial contaminated sites for its large-scale application. [Display omitted] • Biochar application is a promising strategy for remediation of contaminated soil. • Removal of emerging contaminants from soil by biochar is explicated emphatically. • Challenges and future prospects of restoring degraded soil by biochar have been illustrated. [ABSTRACT FROM AUTHOR]

Currently, the production of nanobiochar (n-BC) using ball milling is a promising and cost-effective method. Studies concerning the physicochemical properties of bulk biochar (b-BC) in relation to pyrolysis temperature, various feedstocks or types of carrier gas have been thoroughly investigated. However, there is a lack of information on how the mentioned conditions determine the properties of the obtained n-BCs. In this study, b-BCs produced from different feedstocks (willow (WL), sewage sludge (SSL), rice husk (RH) and oilseed rape (OSR)), temperatures (450–750 °C) and carrier gases (N 2 or CO 2) were ball-milled to produce n-BCs. The specific surface area (S BET), elemental composition (C, H, N, O), morphology (SEM), functional groups (FT-IR), and crystalline and amorphous nature of the carbon (RAMAN) were determined. The size of n-BCs depended on the feedstock used (particles ranged from 30 to 87.9 nm). The type of feedstock mostly determined the properties of n-BCs. The most visible differences between n-BCs and b-BCs were observed for surface properties and C content. For all n-BCs, an S BET increase was observed after ball milling, which may enhance the adsorption potential of biochar. The most intense S BET changes were noted for WL-derived n-BCs obtained at 450 °C (increase from 7.2 to 146.3 m2/g) and at 750 °C (increase from 3.9 to 160.8 m2/g) and for RH-derived n-BCs produced at 550 °C (increase from 3.7 to 158.6 m2/g). The C content decreased for n-BCs produced from plant biomass (WL, RH and OSR) and increased (from 20 to 28%) for n-BCs derived from sewage sludge (SSL). Other physicochemical properties mainly depended on the feedstock used for biochar production. [Display omitted] • Most of the properties of n-BCs differ from the properties of b-BCs. • The type of feedstock was the main factor affecting most of the properties of n-BC. • The decrease in particle size leds to increased aromaticity and elevated polarity of the n-BCs. • Ball milling resulted in a pH decrease and an increase in the electrical conductivity (EC) of the n-BCs. [ABSTRACT FROM AUTHOR]

Advanced persulfate oxidation (AOPs) is a promising method for the degradation of organic pollution, but the preparation of economic, high activity, and low toxicity non-heterogeneous catalysts is still difficult. In this study, a novel nanoscale zero-valent iron composite (nZVI@NBC) supported by biochar with nitrogen doping was prepared, applying activated peroxydisulfate (PDS) to degrade 2,4-dichlorophenol (2,4-DCP). Results demonstrated that nZVI@NBC/PDS system has a 11.8-fold higher degradation k obs of 2,4-DCP than the undoped nitrogen sample, and 2,4-DCP was entirely removed within 60 min. Through different analytical techniques, singlet oxygen (1O 2) was the leading reactive oxygen species (ROS), and graphitic and pyridine nitrogen were the key nitrogen species to produce 1O 2. In addition, electrochemical texts and DFT calculation confirmed that nitrogen doping increased the catalyst's electrical conductivity, so that the 2,4-DCP adsorbed to the [nZVI@NBC-PDS] sub-stable complex was direct oxidation by electron transfer. Furthermore, the nZVI@NBC/PDS system exhibited high selectivity in the co-presence of inorganic anions and other pollutants and possessed excellent 2,4-DCP removal rates (>95 % in pH 3–9). The column experiments demonstrated the high potential of nZVI@NBC to remove 2,4-DCP in groundwater. The mechanism of activation of PDS and degradation of organic contaminants by nZVI@NBC, provide a new approach for the remediating the groundwater pollution. [Display omitted] • The nZVI@NBC exhibited stable and efficient activation effect of PDS. • The degradation efficiency of 2,4-DCP can reach nearly 100% in 60 min. • Non-radical 1O 2 was the primary reactive species for 2,4-DCP degradation. • The nZVI@NBC/PDS system degraded 2,4-DCP effectively in the wide pH range of 3–9. • The electron transfer mechanism of the non-radical pathway has been elucidated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar-ferrospinel AFe 2 O 4 nanocomposites were synthesized for PAA activation. • The applied AOP system efficiently degraded CBZ and other PhACs under mild conditions. • CH 3 C(O)OO radicals were identified the dominant active species for CBZ degradation. • Excellent stability and magnetic separability of biochar-CoFe 2 O 4 were observed. • Mechanistic studies were performed using techniques such as In-situ ATR-FTIR. Peracetic acid (PAA)-based advanced oxidation processes (AOPs) are promising technologies for the efficient treatment of persistent contaminants in wastewater. In this study, three different magnetic biochar (BC)-ferrospinel AFe 2 O 4 (A = Cu, Co, or Mn) nanocomposites were synthesized through a combined sol–gel/pyrolysis process for the activation of PAA to degrade carbamazepine (CBZ). The following order of efficiency was observed for CBZ degradation in the presence of PAA: BC-CoFe 2 O 4 (100 %) > BC-MnFe 2 O 4 (7 %) ≈ BC-CuFe 2 O 4 (7 %). In addition, 0.8 mM PAA, 0.3 g/L catalyst, nearly neutral pH, and 333 K were identified as the optimal operating parameters for the degradation of 1 mg/L CBZ in the BC-CoFe 2 O 4 /PAA system. Mechanistic studies revealed that CH 3 C(O)OO radicals are the dominant active species for the degradation of CBZ in the BC-CoFe 2 O 4 /PAA system, and the continuous conversion of Co(II) to Co(III) in this system is responsible for the generation of these radicals. In addition, the water matrices (e.g., humic acid (20 mg/L), NaCl (0.05 M), and NaNO 3 (0.01 M)) played negligible roles in the degradation of CBZ in the BC-CoFe 2 O 4 /PAA system. This system exhibited highly selective and reactive degradation of organic pollutants with electron-rich groups (e.g., CBZ (0.36 min−1), sulfamethoxazole (0.12 min−1), and diclofenac (0.28 min−1)). Furthermore, the degradation products of CBZ were identified, and possible degradation pathways and toxicity of these transformation products were proposed. The BC-CoFe 2 O 4 /PAA system demonstrated outstanding degradation performance in dynamic systems and real wastewater treatment applications. This study describes the performance of an efficient and easy-to-separate catalyst for the activation of PAA. This study facilitates the development and application of PAA-based AOPs for wastewater treatment. [ABSTRACT FROM AUTHOR]

• Na 2 S 2 O 4 , biochar, and micron iron were reunited by wet and dry ball milling. • Wet ball milling promoted faster and complete Cr(VI) removal (100 % in 80 min) • The composite of wet ball milling presented excellent anti-ageing property. • Higher electron selectivity was obtained (59.15% for wet and 46.72% for dry) • Replacing oxides with sulfides facilitated high iron cycling for Cr(VI) removal. Obstacles such as aggregation and low activity of micron zero-valent iron in pollutant treatment could be overcome by sulfidation and biochar support. Ball milling is a promising method for the preparation of iron-based composites but the milling atmosphere is critical. To maximize the reactivity and identify the effects of ball mill atmosphere, ball milling technology under wet and dry atmosphere was applied to prepare composites from mZVI, Na 2 S 2 O 4 , and pine wood biochar (BC) for Cr(VI) removal. The results showed that S-mZVI/BC-wet was highly dispersible with more FeS 2 coverage and thus more efficient on Cr (VI) removal than S-mZVI/BC-dry (99.9 % removal in 80 min vs. 87.9 % removal in 24 h) at the optimum Fe: C mass ratio (1:1), S: Fe molar ratio (1:10), and reaction conditions. Cr(VI) was adsorbed by a spontaneous, endothermic mechanism that combined physisorption and chemisorption. The reduction process was vulcanization efficiency and iron cycle dependent. Reduction outperformed adsorption on the Cr(VI) removal and high reduction rateswere electron-selectively related (59.15 % for S-mZVI/BC-wet and 46.72 % for S-mZVI/BC-dry), implying S-mZVI/BC-wet was more capable. S-mZVI/BC-wet presented excellent anti-ageing property and slightly inferior regeneration performance. In conclusion, the composite prepared by wet ball milling have excellent performance in rapid and complete removal of Cr(VI), and S-mZVI/BC-wet has superior potential in acidic wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A philic-CO 2 supercarbon was derived from rice husk waste by a new process. • It possessed the max specific surface area in reported biochars (4230 m2 g−1) • It possessed the max CO 2 uptake capacity in the reported biochars (341.5 mg g−1) • This study gave a new way to generate rich ultra-micropores and C-F groups in char. A super-carbon material as adsorbents of CO 2 were prepared with rice husk waste by a new two-step process, pyrolysis-activation and HF post-desilication process. This paper was focused on investigating the boosting effect and mechanism of post-desilication. It was found that the function of the post-desilication was considerably different from that of the reported pre-desilication. It could not only effectively remove Si element from rice husk biochar (RHC) but also significantly improve its performance, producing a super-biocarbon with a well-developed pore structure, rich C-F groups, and a 4230-m2 g−1 surface area, which is the max surface area of known biocarbon. It could adsorb 341.5 mg g−1 CO 2 , a max CO 2 adsorption capacity of reported biocarbon, and its CO 2 /N 2 and CO 2 /H 2 O adsorption selectivity index reached as high as 22.2 and 2.1, respectively. The large surface area was mainly originated from the expansion effect of SiF 4 gas from the post-desilication, generating numerous ultra-microspores, while these C-F groups were generated by the co-reactions of the post-desilication. The ultra-high adsorption capacity was mainly from the fill-adsorption driven by the size effect of these ultra-micropores and the strong CO 2 -affinity of C-F groups, and the adsorption selectivity was confirmed to depend on water-resistant and CO 2 -philic characteristics of its C-F groups by theoretical calculations and experimental observations. These findings presented not only an advanced CO 2 -capture material but also a facile way to tailor textural structure of other biochars. [ABSTRACT FROM AUTHOR]

[Display omitted] • Turn C. glomerata alga from environmental issue to strong membrane modifier. • Functionalizing biochar by MOF to attain modifier of advanced characteristics. • Significant salts and dye rejections achieved by the modified MMMs. • Water flux and fouling resistance enhanced by the incorporation of novel modifiers. • Long-term stability of PES MMMs was achieved when modified by novel modifiers. UiO-66-NH 2 metal–organic framework nanoparticles and carbonaceous biochar prepared from the pyrolysis of Cladophora glomerata alga are introduced as novel modifiers and employed to manipulate polyethersulfone (PES) mixed matrix membranes. The membranes were fabricated through immersion precipitation method and fully assessed through X-ray diffraction pattern, field emission scanning electron microscopy, contact angle, atomic force microscopy, and zeta potential analysis. The membrane performances were also examined by water flux, fouling resistance, and solute rejection. The results indicated that the modified membranes manipulated by 0.2–0.8 wt% of modifier had smoother surfaces than the pristine PES membrane. Moreover, by loading the modifiers in the membrane bulk, the zeta potential was changed from negative to positive values. All the modified membranes revealed superior filtration performance compared to that of the pristine PES membrane. In the modified membrane of the best performance, water flux was increased to up to 85% and contact angle was decreased to 43°. Due to the uniform distribution of modifiers on the membrane surface, and thereby, formation of a barrier layer, up to 98.5% of Reactive Blue 50 dye was rejected by the modified membranes. Salt rejections were also improved in the membranes tailored by the introduced modifiers. Furthermore, through the fouling experiments conducted by humic acid and bovine serum albumin, just 12.9 and 34% reductions in water fluxes were recorded for the modified membrane of the best performance. The experimental results indicated that the higher flux recovery ratios could also be expected for all the membranes modified by the novel hydrophilic modifiers. [ABSTRACT FROM AUTHOR]

Biochar-based phase change materials (PCMs) are suitable for energy conservation to regulate the environment of greenhouses, but would benefit from higher specific surface area biochar to increase the polyethylene glycol (PEG) loading and enhanced thermal conductivity to promote efficient heat transfer. Moreover, since solar radiation is not constant for photo-thermal conversion, a material with an additional energy conversion process, e.g. electro-thermal conversion, would be advantageous. Herein, maize straw-derived activated porous biochar nanosheets were prepared and impregnated with PEG to afford PCMs. Due to their high specific surface area, the PEG loading capacity in the biochar nanosheets reaches 88.9%, with no leakage observed during phase transitions. The latent heat and photothermal conversion efficiency of the materials increase with the loading content of PEG. Hierarchical porous structures in the biochar nanosheets endow the material with a high thermal conductivity exceeding 0.585 W m−1 k−1. In addition, electro-thermal conversion of the materials was achieved due to increased graphitization of the biochar nanosheets. The electrical conductivity and electro-thermal conversion efficiency decrease with the loading content of PEG. The material with 85.7% PEG content is the most favorable in terms of thermal conductivity as well as light- and electro-driven phase change behaviors. [Display omitted] • Dual-driven biochar nanosheets/polyethylene glycol phase change materials were prepared. • The composite phase change materials show good thermal and shape stability. • Increased polyethylene glycol accelerates latent heat and photo-thermal conversion, but retards electro-thermal conversion. • Biochar nanosheets with 85.7% polyethylene glycol loading are the most favorable material for dual-driven phase change. [ABSTRACT FROM AUTHOR]

The utilization of waste lignin to produce bio-oil rich in aromatics aromatic hydrocarbons is promising and attractive for a wide range of applications. Fe-modified lignin biochar (xFe/ALC) prepared using a one-step method was utilized as catalysts to investigate their impact on product distribution, aromatic hydrocarbon generation, and pathways during ex-situ catalytic fast pyrolysis of enzymatic hydrolysis lignin. The results revealed that the addition of Fe enhanced the production of gas products such as H 2 , while decreasing bio-oil yield. The lowest bio-oil yield, at 12.10 wt%, was observed at a Fe loading of 25 wt%, however the relative content of aromatic hydrocarbons reached a maximum value of 16.24 area%. Compared to the pyrolysis of lignin alone, their contents increased by 2.46 times, with the content of monocyclic aromatic hydrocarbons (toluene, ethylbenzene, styrene, xylene) increasing by 1.5–3.8 times. Spent 25Fe/ALC had good stability on the production of aromatic hydrocarbons. Compared with non-catalytic pyrolysis of lignin, the aromatic hydrocarbons content for spent 25Fe/ALC after four cycles increased by 26.70%. [Display omitted] • Fe modified biochar was synthesized by enzymolysis lignin using a one-pot method. • The loading of Fe could regulate the structure and acidity of lignin biochar. • Fe/ALC catalysts were used for ex-situ catalytic pyrolysis of enzymolysis lignin. • The aromatics content for 25Fe/ALC was 2.46 times higher than that without catalysts. [ABSTRACT FROM AUTHOR]

This study addresses the preparation of sludge biochar through a procedure that combines steam pyrolysis in a wide range of temperature (500–900 ºC) and acid treatment with HCl (performed before or after the pyrolysis). The acid washing after the pyrolysis maximizes BET surface area due to pore unblocking, thus making visible the pore structure generated. The drawback of the acid washing is the lower yield obtained (compared to the acid pretreatment), as well as the loss of the magnetic properties of sludge biochar. The acid pretreatment requires temperatures above 700 ºC to have a beneficial effect, due to the occurrence of additional reactions of the incorporated HCl with sludge constituents. The pretreatment results in materials with a high degree of microporosity. Among the reactions favoured, of interest is the development of magnetite in the whole temperature range. The activation protocol used in this study (especially the procedure that includes the acid pretreatment) is effective to generate biochar with magnetic properties through the transformation of the Fe introduced during the water treatment process, without adding a source of Fe. The presence of magnetite is an advantage for the reuse of sludge biochars in wastewater treatment. • Acid washing after steam activation greatly enhances porosity due to pore unblocking. • Acid pretreatment produces biochars with a high degree of microporosity. • Acid pretreatment leads to the formation of magnetite in the whole temperature range. • The acid treatment results in the generation of C=O, -OH and -NH functionalities. • The activation protocol is effective to produce magnetic biochar without adding Fe. [ABSTRACT FROM AUTHOR]

Thermochemical treatments like pyrolysis and gasification, were proposed to circumvent hydrolysis bottleneck of conventional 2nd generation biorefineries. Within this big-picture, the target of this article was to establish the type and amount of bioavailable matter that can be obtained through intermediate pyrolysis of biomass followed by gasification of biochar. To establish the amount of "chemical energy" partitioned among different products' chemical oxygen demand (COD), which is proportional to higher heating value (HHV) and often utilized for biological systems, was applied for the evaluation of thermochemical conversion of a lignocellulosic feedstock (fir wood). The most abundant product of intermediate pyrolysis was biochar, which retains from 33 % to 40 % of feedstock COD (with temperatures starting from 450 °C). The yield of water-soluble pyrolysis products (WS) slightly increases from 24 % at 450 °C to 27 % at 650 °C, whereas the yield of WI increases considerably with the same temperature. Pyrolysis temperature showed a minor effect on the composition of WS as revealed by GC-MS analysis of main compounds and size exclusion chromatography. Preliminary gasification experiments, performed at 850 °C under CO 2 atmosphere, provided gasification rates for different biochars, which was equal to 0.004, 0.005, 0.006 min−1 for biochars obtained at 650, 550, and 450 °C respectively. Syngas obtained from gasification of 450 °C and 550 °C biochar was almost tar-free, whereas gasification of 650 °C biochar yielded a detectable amount of tars (0.4 %). Increasing the gasification temperature to 950 °C sharply increases the gasification rate of biochar obtained at 450 °C, allowing to obtain 55% conversion yield. Within the scope of hybrid thermochemical-biological (HTB) processes, the obtained results show that intermediate pyrolysis, when coupled with subsequent 950 °C CO 2 gasification of biochar, can deliver 64% of chemical energy (by COD basis) of the lignocellulosic feedstock as bioavailable constituents, which are defined to syngas and WS based on recent biological studies. Whereas downstream fermentation can process syngas and WS materials in an effective way, such yields could surpass the holocellulose-targeted methods based on hydrolysis. [Display omitted] • Slow Pyrolysis converts wood into bioavailable organic with 40 % yield. • Rising pyrolysis temperature to 650 °C mainly increases water-insoluble products • Char obtained at lower temperatures are more reactive in CO 2 gasification. • 950 °C CO 2 Gasification of 450 °C char delivers an additional 28 % as tar-free syngas. [ABSTRACT FROM AUTHOR]

The disposal of discarded disposable diapers (D3) is a critical eco-technological problem that is exacerbated by the exponential increase in global consumption each year. Global production of D3 is increasing exponentially and approximately 20 billion used diapers are sent to landfills each year, generating more than 3.5 million tonnes of diaper waste that requires almost 500 years to be fully decomposed. The disposal of D3 has resulted in significant environmental issues and public health hazards. The objective of this study was to provide a systematic review and in-depth discussion of the strategies, challenges, and recent breakthroughs in addressing the problems resulting from the generation and disposal of D3. A systematic literature search was conducted using three electronic databases (Google Scholar, Scopus, and ScienceDirect). Four peer-reviewed studies were selected from the 2287 articles found. Thermochemical technology is claimed to be suitable for the treatment and recycling of used diapers, especially with regard to the use of potentially safer and cleaner technologies with minimal costs. It was established that pyrolysis of D3 could yield useful end products with a wide range of applications, hence providing a future research direction to improve the efficiency of these processes in recycling this waste. • Production of D3 is increasing exponentially and approximately 20 billion used diapers are sent to landfills each year. • The temperature setting for the thermochemical procedure of D3 depends on the technique applied (200 – 900 ℃). • Chemical activation slightly enhanced lead removal from 96.2% to 98.2% (KOH) – 99.8% (ZnCl 2). • Reaction conditions (temperature, pressure, and time) are critical impact D3 biochar yield and product quality in pyrolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-modified biochar addition enhanced the total gross NH 4 + immobilization while decreasing the autotrophic nitrification. • AOB dominated N 2 O emissions in paddy soils with or without biochar or Fe-modified biochar amendment under aerobic conditions. • Fe-modified biochar addition decreased total N 2 O emissions mainly by inhibiting AOB activity. We investigated the potential of ferric iron-modified biochar to lessen autotrophic nitrification and lower nitrous oxide (N 2 O) emissions in paddy soils. A 15N tracing incubation was conducted to investigate the changes in soil gross nitrogen (N) transformations under various biochar amendments (control, unmodified biochar, and Fe-modified biochar). Acetylene and 1-octyne were used to assess the relative contributions of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) to N 2 O emission from paddy soil. The Fe-modified biochar increased the rate of NH 4 + immobilization by 26 % and 383 % compared to the control and unmodified biochar treatments, respectively. The gross rate of autotrophic nitrification was reduced to 5.43 μg N g−1 d−1 in the Fe-modified biochar treatment, compared to 6.74 μg N g−1 d−1 in the control treatment and 9.38 μg N g−1 d−1 in the unmodified biochar treatment. Soil pH had varying effects on N 2 O emissions involving AOB and AOA. The N 2 O yields of AOA were more sensitive to Fe-modified biochar applications. AOB, specifically the Nitrosopira -AOB genus, dominated N 2 O production in all treatments. Overall, this study suggests that Fe-modified biochar holds greater potential than unmodified biochar in reducing N 2 O emissions from paddy soils by stimulating NH 4 + adsorption, restraining autotrophic nitrification rates, and AOB-dominant N 2 O production pathways. [ABSTRACT FROM AUTHOR]

Ball milling technology was employed to increase the adsorption capacity of biochar with respect to methylene blue as a model pollutant. Comparative studies on the adsorption ability were conducted on ball-milled biochar and biochar chemically modified by oxidation and alkaline treatment, showing that ball milling produces higher performances since increases available active sites. The particle size reduction, with the consequence of an increase in the surface area was hypothesized to be responsible for the high removal efficiency. The adsorption kinetics follow s a pseudo-second-order model, implying that the process is affected by chemisorption. Moreover, the Langmuir model proved that the maximum monolayer adsorption capacity increased to 185.18 mg/g. Design of experiments allowed for evaluating the pH and initial concentration values, which maximized the removal efficiency. The milled biochar was also regenerated and reused over six times, resulting in a drop of only 1 %. [Display omitted] • Ball milling technology increases the adsorption capacity of biochar with respect to methylene blue as a model pollutant. • Compared to chemically modified biochars, ball-milled biochar showed higher adsorption performance. • The adsorption kinetics follow a pseudo second-order model implying that the process is affected by chemisorption. • The milled biochar was also regenerated and reused over six times resulting in a drop of only 1 %. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive investigation into the physicochemical properties of banana peel waste (BPW) and its potential for thermochemical conversion into bioenergy and value-added chemicals, supported by the results of kinetics, thermodynamics, in-situ volatile products, and biochar analysis. The physicochemical analysis confirms its potential as a source of renewable fuels and valuable chemicals. Subsequently, based on the TGA outcomes, both kinetic and thermodynamic analysis were conducted. The average activation energy (226–257 kJ mol−1), high heating value (19.56 MJ kg−1), Gibbs free energy (118–149 kJ mol−1), and enthalpy change (222–252 kJ mol−1) all underscore the substantial potential of BPW for bioenergy production and its compatibility for co-pyrolysis with other waste materials. Moreover, Py-GC/MS analysis reveals that the pyrolysis of BPW primarily yields volatile products such as acids, aldehydes, alcohols and ketones, offering a potential source of value-added chemicals. Furthermore, the residual solid biochar exhibits an impressive maximum adsorption capacity of 360.18 mg g−1 for Cd(II) in aqueous environments, thereby further highlighting the exceptional quality of BPW-derived biochar as a superior adsorbent for heavy metals. In summary, this study holds significant importance in promoting the efficient utilization of BPW and mitigating the environmental pollution resulting from improper disposal. [Display omitted] • Kinetic and thermodynamic parameters were calculated to understand BPW pyrolysis behavior. • Acids, aldehydes, alcohols and ketones are the predominant volatile products. • Biochar exhibits excellent adsorption performance towards Cd(II). • BPW emerges as an appealing feedstock for the bioenergy and value-added chemicals production. [ABSTRACT FROM AUTHOR]

Application of biochar derived from biomass resources in soil is an encouraging method to decelerate global warming via carbon sequestration. While there has been extensive research on the priming effect of biochar on the mineralization of native soil organic carbon (nSOC), its correlation with soil organic carbon (SOC) structural variations remains poorly understood. A series of incubation experiments with soils amended with biochar prepared at 300 °C, 450 °C, and 600 °C were performed to explore the shifts in nSOC structure and reveal the interconnections among soil properties, SOC structural variation, and the priming effect induced by biochar. Biochar exhibited an "inhibitory concentration" on soil microorganisms, where 1 % biochar enhanced bacterial and fungal richness and diversity, while 3 % biochar reduced bacterial richness and diversity although soil nutrient conditions were improved. Biochar-treated soil had higher humic acid- and humin-like fractions (HAL and HML) but lower fulvic acid-like components (FAL). Moreover, bulk SOC, FAL, HAL, and HML of soils with 300 °C and 450 °C biochar contained more aromatic-type species (e.g., lignin). Such changes were related to improvement of the soil nutrient condition and shifts in microbial community structures, in addition to the "accumulation of biochar-derived OC in the nSOC pool". Stable carbon isotopes indicated that the inhibitory effect on SOC mineralization (−94.5 to −8.0 mg CO 2 -C kg−1 soil) induced by biochar was significantly explained by the change in FAL and HAL contents. The findings improved the understanding of the carbon sequestration potential of biochar in soils for SOC structural modification. • Biochar showed an "inhibitory concentration" on soil microorganisms. • Biochar-added soils contained more humic acid- and humin-like fraction. • Structure change in SOC was related to soil nutrient and biological condition shift. • Increase in stable SOC partly explained the negative priming effect of biochar. [ABSTRACT FROM AUTHOR]

Biochar-manure co-compost (BM) has garnered considerable attention as a promising soil amendment for improving nutrient retention and mitigating the emission of greenhouse gases (GHGs). However, its efficacy often varies largely from one soil to another. By comparing soil CO 2 and N 2 O effluxes, solution chemistry, enzyme activities, and the abundances of N-cycle genes between BM and manure compost (M) across three soils of different texture classes through microcosm incubations, we aimed to develop biophysical mechanics to untangle the soil-dependent efficacy of BM in mediating soil carbon and nitrogen transformation processes. Compared to M addition, BM addition significantly reduced soil CO 2 and N 2 O emissions, but its effectiveness was soil texture-dependent, being strongest for CO 2 and N 2 O in fine-textured clay loam and coarse-textured sand, respectively. Such soil texture-dependent effects of BM versus M were also observed in soil enzyme activities and gene copy numbers of ammonia-oxidizing bacteria and denitrifiers. Our datasets suggest that BM interacted strongly with soil texture to modulate the pore scale-based diffusion of oxygen, thereby creating divergence in the aeration status among soils. Sequentially, soil phenol oxidase activity was greater in BM than in M under more aerobic conditions but no difference between BM and M in oxygen-limited soils. The balance between oxygen depletion due to microbial respiration of organic amendments and oxygen diffusion through soil/biochar pores also shaped the activities of nitrifying and denitrifying prokaryotes differently between coarse- and fine-textured soils. This logic model well-explained the magnitude of change in soil-dependent CO 2 and N 2 O emissions from organic amendments. The knowledge gained in this work will likely have profound practical ramifications for optimizing BM efficacy in mitigating the GHGs emission. Graphic abstract [Display omitted] • Impact of biochar-manure compost (BM) on CO 2 and N 2 O emissions is soil dependent. • BM interacted with soil texture to modulate pore scale-based oxygen diffusion. • Oxygen level regulated by BM addition affected abundance of N-cycling prokaryotes. • A biophysical mechanism is developed to explain the soil dependence of BM efficacy. [ABSTRACT FROM AUTHOR]

Per- and poly-fluoroalkyl substances (PFAS) are synthetic chemicals widely used in everyday products, causing elevated concentrations in drinking water and posing a global challenge. While adsorption methods are commonly employed for PFAS removal, the substantial cost and environmental footprint of commercial adsorbents highlight the need for more cost-effective alternatives. Additionally, existing adsorbents exhibit limited effectiveness, particularly against diverse PFAS types, such as short-chain PFAS, necessitating modifications to enhance adsorption capacity. Biochar can be considered a cost-effective and eco-friendly alternative to conventional adsorbents. With abundant feedstocks and favorable physicochemical properties, biochar shows significant potential to be applied as an adsorbent for removing contaminants from water. Despite its effectiveness in adsorbing different inorganic and organic contaminants from water environments, some factors restrict its effective application for PFAS adsorption. These factors are related to the biochar properties, and characteristics of PFAS, as well as water chemistry. Therefore, some modifications have been introduced to overcome these limitations and improve biochar's adsorption capacity. This review explores the preparation conditions, including the pyrolysis process, activation, and modification techniques applied to biochar to enhance its adsorption capacity for different types of PFAS. It addresses critical questions about the adsorption performance of biochar and its composites, mechanisms governing PFAS adsorption, challenges, and future perspectives in this field. The surge in research on biochar for PFAS adsorption indicates a growing interest, making this timely review a valuable resource for future research and an in-depth exploration of biochar's potential in PFAS remediation. [Display omitted] • Methods of preparing biochar adsorbents for PFAS adsorption were summarized. • Mechanisms of PFAS adsorption on biochar adsorbents were comprehensively explored. • The effectiveness of biochar for PFAS removal is closely tied to pyrolysis conditions. • Activated biochars exhibited enhanced PFAS adsorption performance compared to pristine biochars. • Biochar Composites showed higher PFAS adsorption performance. [ABSTRACT FROM AUTHOR]

In the face of increasing nitrogen demand for crop cultivation driven by population growth, this study presents a sustainable solution to address both the heightened demand and the energy-intensive process of nitrogen removal from wastewater. Our approach involves the removal of nitrogen from wastewater and its subsequent return to the soil as a fertilizer. Using biochar derived from Aesculus turbinata fruit shells (ATFS), a by-product of post-medical use, we investigated the effect of pyrolysis temperature on the NH 4 –N adsorption capacity of ATFS biochar (ATFS-BC). Notably, the ATFS-BC pyrolyzed at 300 °C (ATFS-BC300) exhibited the highest NH 4 –N adsorption capacity of 15.61 mg/g. The superior performance of ATFS-BC300 was attributed to its higher number of oxygen functional groups and more negatively charged surface, which contributed to the enhanced NH 4 –N adsorption. The removal of NH 4 –N by ATFS-BC300 involved both physical diffusion and chemisorption, with NH 4 –N forming a robust multilayer adsorption on the biochar. Alkaline conditions favored NH 4 –N adsorption by ATFS-BC300; however, the presence of trivalent and divalent ions hindered this process. Rice plants were cultivated to assess the potential of NH 4 –N adsorbed ATFS-BC300 (NH 4 -ATFS-BC300) as a nitrogen fertilizer. Remarkably, medium doses of NH 4 -ATFS-BC300 (594.5 kg/ha) exhibited key agronomic traits similar to those of the commercial nitrogen fertilizer in rice seedlings. Furthermore, high doses of NH 4 -ATFS-BC300 demonstrated superior agronomic traits compared to the commercial fertilizer. This study establishes the viability of utilizing ATFS-BC300 as a dual-purpose solution for wastewater treatment and nitrogen fertilizer supply, presenting a promising avenue for addressing environmental challenges. [Display omitted] • Biochar from Aesculus turbinata fruit shells (ATFS) is a valuable resource. • ATFS was used as an adsorbent for NH 4 –N removal in wastewater. • ATFS pyrolyzed at 300 °C showed the highest NH 4 –N adsorption. • The NH 4 –N adsorbed ATFS-BC was a beneficial nitrogen fertilizer for rice growth. [ABSTRACT FROM AUTHOR]

In this comprehensive study, highlights emerging environmentally friendly methods to eliminating hazardous heavy metals from contaminated water, with an emphasis on bioremediation and biosorption. Breakthroughs, such as the combination of biological remediation and nanotechnology to improve the elimination of metals effectiveness and the use of genetically modified microbes for targeted pollutant breakdown. Developing biosorption materials made from agricultural waste and biochar, this indicates interesting areas for future research and emphasizes the necessity of sustainable practices in tackling heavy metal contamination in water systems. There seems to be a surge in enthusiasm for the utilization of biological remediation and biosorption methods as sustainable and viable options for eliminating heavy metals from contaminated water in the past couple of decades. The present review intends to offer an in-depth review of the latest understanding and advances in the discipline of biological remediation methods like bioaccumulation, biofiltration, bio-slurping, and bio-venting. Biosorption is specifically explained and includes waste biomass as biosorbent with the removal mechanisms and the hindrances caused in the process are detailed. Advances in biosorption like microbes as biosorbents and the mechanism involved in it. Additionally, novel enhancement techniques like immobilization, genetic modification, and ultrasound-assisted treatment in microbial sorbent are clarified. However, the review extended with analyzing the future advances in the overall biological methods and consequences of heavy metal pollution. [Display omitted] • Biological techniques for the effective removal of heavy metal ions were discussed. • Various biosorbents sources, mechanism and influencing parameters were summarized. • Microbes surface qualities are modified using genetic modifications are reviewed. • Future and advanced views on biological adsorption techniques were elucidated. [ABSTRACT FROM AUTHOR]

The non-free radical oxidation pathway (PMS-NOPs) of peroxymonosulfate (PMS) holds significant promise for practical wastewater treatment applications, owing to its low oxidation potential, high PMS utilization rate, and robust anti-interference capability in the degradation of pollutants. A novel activator copper nitrogen co-doped porous biochar (Cu-N-BC) with rich defect edges and functional groups was obtained by adding Cu and N to the biochar matrix generated by sodium alginate through pyrolysis in this study. Under the condition of 1 mM PMS, 30 mg/L activator was used to activate PMS and achieve efficient degradation of 10 mg/L paracetamol (PCT) within 15 min, with a high reaction rate constants (k obs) of 0.391 min−1. The activation mechanism of the Cu-N-BC/PMS/PCT system was a non-radical activation pathway with the dominance of singlet oxygen (1O 2) and the presence of catalyst-mediated electron transfer. The graphite nitrogen, pyridine nitrogen, and Cu–N coordination introduced by Cu/N co-doping, as well as the carbon skeleton and C O functional group of biochar, were considered active sites that promote the 1O 2 generation. The Cu-N-BC/PMS system exhibits strong stability, eco-friendliness, effective mineralization, and interference resistance across diverse pH levels (3–11) and interfering ions, including Cl−, H 2 PO 4 −, NO 3 −, SO 4 2−, and humic acid. Remarkably, it efficiently degrades PCT in tap and lake water, achieving a notable 63.73% TOC mineralization rate, with leached copper ions below 0.02 mg/L. This research introduces a novel method for obtaining metal nitrogen carbon activators and enhances understanding of PMS non-radical activation pathways and active sites. [Display omitted] • A strategy of co-doping biochar was developed to construct a non-radical activation mechanism of PMS. • The degradation efficiency of paracetamol can reach 100% with low-dose activators. • Singlet oxygen and electron transfer were responsible for the degradation. [ABSTRACT FROM AUTHOR]

Carbon-based biowaste incorporated with inorganic oxides as a composite is an enticing option to mitigate heavy metal pollution in water resources due to its more economical and efficient performance. With this in mind, we constructed manganese-doped iron oxide microflowers resembling the dandelion-like structure on the surface of cold plasma-treated carbonized rice husk (MnFe 2 O 3 /PCRH). The prepared composite exhibited 45% and 19% higher removal rates for Cu2+ and Cd2+, respectively than the pristine CRH. The MnFe 2 O 3 /PCRH composite was characterized using XRD, FTIR, FESEM, EDX, HR-TEM, XPS, BET, TGA, and zeta potential, while the adsorption capacities were investigated as a function of pH, time, and initial concentration in batch trials. As for the kinetics, the pseudo-second-order was the rate-limiting over the pseudo-first-order and Elovich model, demonstrating that the chemisorption process governed the adsorption of Cu2+ and Cd2+. Additionally, the maximum adsorption capacities of the MnFe 2 O 3 /PCRH were found to be 122.8 and 102.5 mg/g for Cu2+ and Cd2+, respectively. Based on thorough examinations by FESEM-EDS, FTIR, and XPS, the possible mechanisms for the adsorption can be ascribed to surface complexation by oxygen-containing groups, a dissolution-precipitation of the ions with –OH groups, electrostatic attraction between metal ions and the adsorbent's partially charged surface, coordination of Cu2+ and Cd2+ with π electrons by aromatic/graphitic carbon in the MnFe 2 O 3 /PCRH, and pore filling and diffusion. Lastly, the adsorption efficiencies were maintained at about 70% of its initial adsorption even after five adsorption-desorption cycles, displaying its remarkable stability and reusability. [Display omitted] • Mn-doped Fe 2 O 3 microflowers were decorated on plasma-treated biochar (MnFe 2 O 3 /PCRH). • The MnFe 2 O 3 /PCRH was thoroughly analyzed before and after Cu2+ and Cd2+ adsorption. • Kinetics, isotherms, and thermodynamic studies showed its excellent adsorption capability. • Mechanisms underlying ions adsorption by MnFe 2 O 3 /PCRH were further clarified. • The reusability of the MnFe2O3/PCRH proved its economic sustainability. [ABSTRACT FROM AUTHOR]

Due to the importance and economic value of gold in various applications, recovering gold from waste streams like tailings and industrial wastewater is essential. Biochar with a high surface area and porosity is considered a potential low-cost adsorbent for gold reclaiming from aqueous media. Therefore, this study aims to develop a high-quality biochar with excellent physicochemical properties to efficiently remove gold from aqueous media. To accomplish this, biochar was obtained from pyrolysis of ironbark (IB) biomass at 500 °C which has a surface area of 493.79 m2/g. Subsequently, the biochar was investigated for adsorption of gold from aqueous media, which exhibited a maximum adsorption capacity of 858 mg/g. Isotherm results showed that the adsorption of gold by biochar followed the Langmuir model, indicating monolayer adsorption. Further, response surface methodology (RSM) and an artificial neural network (ANN) combined with the Salp Swarm Algorithm (SSA) were used to analyze the generated results (ANN-SSA). The RSM prediction model fit was adequate (R2 = 0.99). However, comparing the statistical data revealed that ANN-SSA outperformed RSM in predicting experimental results. Overall, this study suggested that biochar derived from IB biomass could be used as a potential adsorbent to recover gold from an aqueous solution. This article presents a unique and innovative study on the utilization of ironbark biochar for the purpose of gold adsorption. [Display omitted] • A novel biochar produced from ironbark was investigated for Au adsorption. • The biochar achieved a maximum Au adsorption of 858 mg/g under optimized conditions. • ANN model showed a better Au adsorption prediction compared to the RSM model. • Physisorption and electrostatic attraction were the dominant Au adsorption mechanism. • Au adsorption followed the Langmuir model, indicating a monolayer surface adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • BC/ZnO composites were successfully synthesized from wood wastes. • The BC/30 %ZnO composite showed enhanced photocatalytic performance than pure ZnO. • The composite presented good reusability and stability after 4 cycles of use. • First study applied BC/ZnO composite for NAs mixture photocatalytic degradation. • Over 95 % of NAs in mixture were degraded by BC/30 %ZnO after 6 h solar irradiation. Naphthenic acids (NAs) present in oil sands process water (OSPW) have brought increasing environmental concerns due to their potential risk to aquatic and mammalian species. In this study, sustainable biochar zinc oxide (BC/ZnO) composites were synthesized using wood waste with different ZnO content and applied under simulated solar light for the photocatalytic degradation of different NAs for the first time. The best experimental conditions were determined as 0.5 g/L BC/30%ZnO and 4 h of simulated solar irradiation time, achieving 93.7 % degradation of cyclohexanecarboxylic acid (CHA) following the pseudo-first order kinetics. BC, with a porous structure and roughened surface, acted as an excellent platform for ZnO particles and an electron reservoir to inhibit the recombination of photogenerated electron-hole pairs. Hydroxyl radicals (•OH) were identified to play the dominant role in CHA degradation, and the enhanced photocatalytic performance of the BC/30%ZnO composite was proved by more •OH species detected compared to synthesized ZnO. The composite showed good reusability and stability after 4 successive cycles of use, still achieving 92.9 % degradation of CHA. Moreover, this is the first study applying BC/30%ZnO composite for the simultaneous degradation of a complex mixture of eight NAs with significantly different chemical structures. The competition kinetics were observed among different NAs in the mixture, resulted in over 95 % degradation of total NAs after 6 h treatment. By applying wood waste-based BC/ZnO composite with excellent photocatalytic performance in combination with solar light as green energy source, this research highlights a promising sustainable approach for real OSPW remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe(II)-bearing minerals alone are non-reactive to trichloroethylene reduction. • Fe(II)-bone char could effectively reduce trichloroethylene to acetylene. • The Fe(II)-bone char were prepared by simple mixing in water. • Fast kinetics did not guarantee high electron efficiency. • Suitable crystallinity of Fe(II) enable steady and long lasting TCE reduction. Fe(II)-bearing minerals might be able to drive the attenuation of chlorinated ethene in soil and groundwater, however, with relatively slow kinetics. In this study, bone char(BC) was selected as an efficient and benign catalyst to prepare composites with three different Fe(II)-bearing minerals (Green rust (GR), Fe(OH) 2 and FeS), respectively, for enhanced trichloroethylene (TCE) dehalogenation. The kinetics experiment demonstrated that the presence of BC could effectively switch on the TCE dehalogenation by these solids, while these Fe(II)-bearing minerals alone can barely reduce any TCE. Surprisingly, the Fe(OH) 2 -BC showed fastest TCE reduction rate, followed by GR-BC and FeS-BC in sequence. Acetylene was confirmed as the major dehalogenation products while other chlorinated byproducts were hardly detected. The electron efficiency (η e) for TCE reduction was further calculated and compared among these BC amended systems, the results show that the highest η e value was recorded in GR-BC system as 33.14% with high loading of TCE. Solid phase characterization confirmed that the high loading of amorphous Fe(II) on the BC surface might effectively improve the TCE dehalogenation kinetics, while the well crystallized Fe(II)-bearing minerals would increase the electron efficiency. According to this mechanism, it might be possible to achieve balance between kinetics and electron efficiency. Stress resistance test in real groundwater matrix and life cycle analysis (LCA) was conducted to further verify the application potential of these composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • BC-SIPN particles selectively adsorb TlOH (aq) , easing Tl concentration dependence. • Hydrogen bonding-electrostatic interactions formed between TlOH (aq) and BC-SIPN. • SIPN enhances particle stability, extending lifetime for sustained efficacy. • Electro-induction directly oxidizes Tl(I) to Tl(III) by BEC on BC-SIPN particles. • Gel-minerals with 0.073 % Tl content exhibit recycling potential. Electrochemical techniques for thallium (Tl) treatment face a substantial challenge linked to the concentration of Tl(I), hindering the efficient removal and recovery of trace Tl(I) (μg L−1). In response, we synthesized hydrogel particles incorporating biochar (BC) within semi-interpenetrating polymer networks (SIPN), showcasing robust selectivity for Tl(I). These biochar-embedded-SIPN hydrogel particles (BC-SIPN particles), employed as dispersed electrodes, facilitated the targeted oxidation and enrichment of Tl(I) through electro-induction. Research outcomes elucidate the adept mitigation of the "efficiency-dependent concentration" behavior by electro-induced BC-SIPN particles during the reaction process. Under optimized conditions (pH 12, 2 V cm−1, 30 min), Tl(I) removal efficiency surpassed 98 % at an initial concentration of 100 μg L−1. The SIPN structure enhanced particle stability, and after seven cycles of enrichment in a 100 μg L−1 Tl(I) environment, BC-SIPN particles achieved a Tl content of 0.073 %, meeting Tl mineral content standards and promoting the recovery of scarce Tl resources. First-principles calculations underscore the pivotal role of hydrogen bond-electrostatic interactions between TlOH (aq) and particles in driving selective Tl(I) adsorption. Insights from quenching and capture reactions reveal a predominant direct oxidation pathway of Tl(I) to Tl(Ⅲ), complemented by indirect oxidation driven by reactive oxygen species, including OH, O- 2 and 1O 2. This study presents an innovative approach for trace Tl(I) wastewater treatment, simultaneously mitigating the "efficiency-dependent concentration" phenomenon, and underscores the transformative potential of electro-induced BC-SIPN hydrogel particles in offering sustainable solutions for Tl(I) removal and resource recovery in environmental stewardship. [ABSTRACT FROM AUTHOR]

[Display omitted] • A biochar composite (ZnS/NBC) was successfully synthesized by one-step pyrolysis of the mixture of Porphyra and ZnCl 2. • ZnS/NBC 10 held high specific surface area, highly graphitized structure and strong photothermal conversion ability. • ZnS/NBC 10 /PMS/light system showed high degradation rate and nearly complete mineralization of CBZ. • The dominant role of 1O 2 , the SO 4 −, OH and electron transfer assist jointly enhanced the degradation of CBZ. • CBZ degradation pathway was proposed based on Fukui index calculations and LC-MS results. Heterogeneous catalysis with peroxymonosulfate (PMS) activation has received increasing attention in recalcitrant contaminants treatment, but multidimensional coupling via engineered biochar materials and photothermal synergy is still rare. Herein, we reported photothermal-synergistic PMS activation by Porphyra -derived porous biochar composites (ZnS/NBC) for carbamazepine (CBZ) degradation. Benefitting from the high specific surface area, highly graphitic structure and strong light-to-heat conversion ability, ZnS/NBC 10 /PMS/light system showed enhanced degradation performance and nearly complete mineralization of CBZ. Meanwhile, this system maintained high degradation efficiency in real water bodies and natural sunlight condition, respectively. Mechanism analysis confirmed that the predominant role of 1O 2 and the auxiliary involvement of SO 4 −, OH and electron transfer jointly contributed to the CBZ degradation. Finally, the possible degradation pathways of CBZ were elaborated based on the liquid chromatography-mass spectrometry results and Fukui index calculations, and the diminishing ecotoxicity of the accompanying degradation intermediate was evaluated using the toxicity estimation software tool. This study provides a new insight for advancing a comprehensive utilization of photothermal conversion and biochar-based PMS activators to organic wastewater purification. [ABSTRACT FROM AUTHOR]

Water scarcity and water-related soil erosion are severely exacerbated by inappropriate human activities and global climate change. Hence, to find a suitable technology to mitigate drought and soil erosion, three consecutive field experiments were conducted to explore the impact of ridge-furrow cropping with biochar amendment on soil water storage, runoff, sediment yield, soil nutrient losses, alfalfa (Medicago sativa L) fodder yield, crop water productivity (WP c), and economic benefit from 2019 to 2021. This experiment was conducted in a split-plot design, taking biochar amendment patterns (no biochar amendment and biochar amendment at a rate of 3× 104 kg ha−1) as a main plot and ridge-furrow technologies (traditional planting, open-ridging, and tied-ridging) as a split-plot. The combination of biochar amendment with ridge-furrow technology, especially tied-ridging technology, increased soil water storage, and captured runoff, sediment, and related soil nutrient losses, consequently increasing alfalfa fodder yield, WP c , and income. During this study, compared to traditional planting, open-ridging depicted an increase in soil water storage by a range of 9.8–39.6 mm, an alfalfa fodder yield boost ranging from 9.8% to 38.6%, and a WP c increase ranging from 0.1 to 16.5 kg ha−1 mm−1. On the other hand, tied-ridging showed greater improvements with soil water storage increasing by 29.1–65.1 mm, alfalfa fodder yield growing by 11.6–44.4%, and WP c advancing by 0.9–17.5 kg ha−1 mm−1. The mean decrease in runoff, sediment, and nutrients (total nitrogen, total phosphorus, and organic matter) loss for open-ridging was 17.9%-37.7%, 46.4%-75.5%, and 40.4%-75.3%, respectively, while for tied-ridging, it was 22.3%-55.5%, 62.1%-87.6%, and 49.0%-87.3%, respectively. Compared to no biochar amendment, soil water storage, alfalfa fodder yield, and WP c for biochar amendment increased by 9.1%-20.4%, 5.8%-52.7%, and 4.6–7.8 kg ha−1 mm−1, respectively, while runoff, sediment, and nutrients loss for biochar amendment decreased by 32.2%-40.9%, 25.5%-55.5%, and 35.9%-53.3%, respectively. Structural equation modeling analysis indicated that the significant direct effect of biochar amendment and ridge-furrow technology on WP c was 0.20 and 0.62, respectively, whereas the significant direct effect of runoff and actual crop evapotranspiration on alfalfa fodder yield was −0.40 and 0.94, respectively. Tied-ridge cropping combined with biochar addition was a highly suggested approach for addressing soil erosion and enhancing alfalfa fodder yields in the Loess Plateau in China. This technology could mitigate soil water scarcity and soil erosion, and give farmers the confidence to invest in this technology in dryland regions. • Ridge-furrow technology with biochar amendment reduced soil erosion. • Ridge-furrow technology with biochar amendment increased crop yield. • Biochar amendment and ridge-furrow technology had a direct effect on water use efficiency. • Runoff and evapotranspiration had a direct effect on alfalfa fodder yield. • Tied-ridge cropping with biochar amendment was recommended. [ABSTRACT FROM AUTHOR]

Biochar application to agricultural fields is an effective carbon sequestration measure that has the potential to reduce N 2 O emissions and increase soil water holding capacity. However, the interaction mechanisms of biochar under deficit irrigation on N 2 O emissions remain unclear. A two-year field experiment is conducted in the Guanzhong Plain, China, in order to quantify the effects of biochar and deficit irrigation on N 2 O emissions from winter wheat–summer maize crop rotation and to investigate the potential mechanisms of nitrification and denitrification. According to the combination of biochar application and actual evapotranspiration-based irrigation scheduling, four treatments are designed (B 1 W 100 : biochar 30 t·ha−1 + ET; B 1 W 80 : biochar 30 t·ha−1+ 0.8 ET; B 0 W 100 : no biochar + ET; B 0 W 80 : no biochar + 0.8ET). The soil N 2 O flux, soil physical and chemical properties, and key functional gene abundance related to N 2 O emissions in nitrification and denitrification at different growth stages are investigated and discussed. Results show that the interaction between deficit irrigation and biochar significantly reduces soil N 2 O emissions. During the wheat and maize season, the application of biochar reduces the N 2 O emissions by an average of 12.9% and 15.2%, respectively. Deficit irrigation also reduces the N 2 O emissions by an average of 17.4% and 15.5%, respectively. Pearson correlation analysis shows that soil N 2 O is significantly correlated with soil water-filled pore space during the phase with intense N 2 O emissions. Soil functional gene abundance is determined at different growth stages for both wheat and maize. Maximum soil denitrification functional gene abundance is observed at the time when wheat and maize enter the stage of their peak growth at the jointing stage. With biochar addition and deficit irrigation, the abundance of nirK and nosZ genes increases and AOB amoA genes decreases. These results suggest that biochar with deficit irrigation is a better solution to reduce N 2 O emissions from agricultural soils. • The interaction of deficit irrigation and biochar reduce N 2 O emissions from wheat-maize rotation croplands. • A sudden increase in N 2 O emissions after irrigation, with soil water-filled pore space (WFPS) as the main regulator. • Deficit irrigation and biochar addition reduced AOB gene abundance and increased nirK and nosZ gene abundance. [ABSTRACT FROM AUTHOR]

To achieve a closed nutrient cycle and more sustainable food production, enhanced nutrient recycling in the agri-food system is a necessity. Pyrolysis is an emerging technology to recycle the nutrient content of sewage sludge. The produced biochar can be used to reduce the need for mineral fertilizers; in addition, pyrolysis can also handle potential pollutants such as microplastics and pathogens present in sewage sludge. In this research, a life cycle assessment (LCA) was carried out to determine the environmental impact of sewage sludge pyrolysis as an alternative to current practices of two different cases of sewage sludge treatment in two municipalities in Sweden. The results indicated that avoiding mineral fertilizer production by using biochar has a significant influence on the environmental benefits. Furthermore, it showed that an integrated system of anaerobic digestion followed by pyrolysis could perform as the most environmental-friendly option for sewage sludge treatment with a lower risk of transferring pollution to the soil. [Display omitted] • Life cycle assessment has been performed to compare the current practice of sewage sludge treatment with alternative of pyrolysis. • Midpoint impact assessments results have been combined with analysis of other factors such as contamination transfer risk to soil, carbon sequestration and legislative aspects. • Avoided mineral fertilizer production shows a significant contribution to the environmental benefit of treatment methods. • Results show that pyrolysis could be an environmental preferable treatment for sewage sludge. • Future research should focus on innovative solutions of sewage sludge treatment which satisfy environment and human health simultaneously. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles were deposited on Douglas fir biochar (Fe 3 O 4 /DFBC) using aqueous, NaOH-induced chemical co-precipitation from Fe2+/Fe3+ salt solutions. Fe 3 O 4 /DFBC was used to remediate As(V)-contaminated water. Kinetics and isotherms were studied. pH 5 was selected as the optimized pH due to low iron leaching and closeness to groundwater pH. Adsorption equilibrium was reached after 3 h, 2 h, and 1 h for 0.5, 5, and 50 mg/L initial As(V) concentrations, respectively. Adsorption was endothermic, and the Langmuir capacity was 6.33 mg/g at 25 °C. Ionic strength, impacts of Fe 3 O 4 /DFBC particle size, and competitive ion/molecule effects during As(V) adsorption were studied. Continuous-flow fixed-bed column breakthrough studies performed at 0.5, 5, and 50 mg/L of As(V) at pH 5 exhibited maximum capacities of 3.47, 3.99, and 3.72 mg/g, respectively. Aqueous potassium phosphate was used successfully for column regeneration. Fe 3 O 4 /DFBC was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Mössbauer spectroscopy before and after As(III) and As(V) adsorption. Mössbauer found the "Fe 3 O 4 " was composed of several phases. A key target was the study of simultaneous toxic As(III) adsorption and its transformation to As(V) from pH 1–13. The highest removal of As(III) and oxidized As(V) was obtained at pH 3. The relationship between iron leaching and pH was investigated and the pH-dependent surface adsorption was monitored using X-ray photoelectron spectroscopy (XPS) from pH 1 to 13. One goal of this study was to enhance the understanding of the adsorption characteristics needed for initial scaling of a treatment facility that can efficiently remediate arsenic-contaminated wastewater. Experiments were conducted using batch and fixed bed continuous flow columns to optimize adsorption process parameters under various circumstances and solution matrices. Another goal was to further establish the surface structures of the chemisorbed arsenates versus pH. [Display omitted] • As(III) can be oxidized to As(V) in anoxic conditions when adsorbed. • Solution effects, dose optimizations, column separations, and Fe2+/3+ leaching versus pH were studied during As(V) removal. • AsO 4 3− adsorption capacity was 6.33 mg/g at 25 °C. • Redox transformation of As(III) to As(V) on Fe 3 O 4 /DFBC was studied from pH 1 to 13. • Mössbauer spectroscopy and pH-dependent XPS aided detailed mechanistic understanding. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel biochar was prepared by low temperature phosphoric acid activation pyrolysis. • Biochar has large specific surface area and abundant oxygen-containing functional groups. • The obtained biochar has excellent performance in the removal of paclobutrazol from water. • Biochar is rich in N and P nutrients and can promote the growth of mung bean seedlings. • The addition of biochar can reduce the bioavailability and phytotoxicity of paclobutrazol in soil. Using biochar to absorb organic pollutants in water and soil is a simple and efficient method. However, most biochar is typically prepared at high temperatures (>500 ℃), resulting in low yield and high production costs and hence limiting its practical applications. This study aimed to prepare biochar (P-BC) through low-temperature (280 ℃) phosphoric acid assisted pyrolysis of cotton stalks. P-BC possessed a large specific surface area (389.96 m2·g−1) and contained abundant oxygen functional groups as well as phosphorous and nitrogen nutrient elements. This study applied P-BC to remove paclobutrazol (PBZ) from water and remediate PBZ-polluted soil. The water adsorption capacity of P-BC was 192.89 mg·g−1. The adsorption mechanisms of P-BC included pore filling, hydrogen bonding, weak electrostatic effects, and π-π interactions. Adding 1 % P-BC to soil contaminated with 10 mg·kg−1 PBZ could alleviate PBZ induced phytotoxicity in mung bean seedlings, ensuring the normal growth of roots and plants. [ABSTRACT FROM AUTHOR]

In recent times, the application of biochar (BC) as an upcoming catalyst for the elimination of recalcitrant pollutants has been widely explored. Here, an iron loaded bamboo biochar activated peroxymonosulphate (PMS) process was tested for removing Congo red (CR) dye from water medium. The catalyst was synthesized using a green synthesis method using neem extracts and characterized using SEM, FTIR, and XRD. The effects of various operating parameters, including solution pH, catalyst dosage, and pollutant dosage, on dye degradation efficiency were examined. The results showed that at the optimized conditions of 300 mg L−1 PMS concentration, 200 mg L−1 catalyst dosage, and pH 6, about 89.7% of CR dye (initial concentration 10 ppm) was removed at 60 min of operation. Scavenging experiments revealed the significant contribution of O 2 •−, •OH, and 1O 2 for dye degradation, with a major contribution of O 2 •−. The activation of PMS was mainly done by biochar rather than iron (loaded on biochar). The catalyst was highly active even after four cycles. [Display omitted] • Application of green synthesized iron-loaded biochar as a PMS activator. • The superior performance of biochar in the activation by PMS. • O 2.•− is the primary oxidant responsible for dye degradation • •OH and 1O 2 were also produced in the catalyst-activated PMS process • SO 4.•− has less contribution to dye degradation [ABSTRACT FROM AUTHOR]

The presence of heavy metals in water pose a serious threat to both public and environmental health. However, the advances in the application of low cost biochar based adsorbent synthesize from various feedstocks plays an effective role in the of removal heavy metals from water. This study implies the introduction of novel method of converting food waste (FW) to biochar through pyrolysis, examine its physiochemical characteristics, and investigate its adsorption potential for the removal of heavy metals from water. The results revealed that biochar yield decreased from 18.4 % to 14.31 % with increase in pyrolysis temperature from 350 to 550 °C. Likewise, increase in the pyrolysis temperature also resulted in the increase in the ash content from 39.87 % to 42.05 % thus transforming the biochar into alkaline nature (pH 10.17). The structural and chemical compositions of biochar produced at various temperatures (350, 450, and 550 °C) showed a wide range of mineralogical composition, and changes in the concentration of surface functional groups. Similarly, the adsorption potential showed that all the produced biochar effectively removed the selected heavy metals from wastewater. However a slightly high removal capacity was observed for biochar produced at 550 °C that was credited to the alkaline nature, negatively charged biochar active sites due to O-containing functional groups and swelling behavior. The results also showed that the maximum adsorption was recorded at pH 8 at adsorbent dose of 2.5 g L−1 with the contact time of 120 min. To express the adsorption equilibrium, the results were subjected to Langmuir and Freundlich isotherms and correlation coefficient implies that the adsorption process follows the Freundlich adsorption isotherm. The findings of this study suggest the suitability of the novel FW derived biochar as an effective and low cost adsorbent for the removal of heavy metals form wastewater. [Display omitted] • Biochar was successfully produced from food waste at various pyrolysis temperatures. • Temperatures significantly affect the physiochemical characteristics of biochar. • Biochar showed effective adsorption capacity towards the removal of heavy metals. • pH 8, 2.5 g L−1 adsorbent dose and 120 min contact time showed high adsorption. • Adsorption equilibrium fitted best with Freundlich adsorption isotherm model. [ABSTRACT FROM AUTHOR]

An important paradigm shift towards the circular economy is to prioritize waste prevention, reuse, recycling, and recovery before disposal is necessary. In this context, a sustainable protocol of converting waste pea peel (wPP) into low-cost carbon nanomaterials for sensing and conversion of p -nitrophenol (p -NP) into value-added paracetamol is being reported. Two fractions of the carbonaceous nanomaterials were obtained after the hydrothermal treatment (HT) of wPP, firstly an aqueous portion containing water-soluble carbon dots (wPP-CDs) and a solid residue, which was converted into carbonized biochar (wPP-BC). Blue-colored fluorescent wPP-CDs displayed excitation-dependent and pH-independent properties with a quantum yield (QY) of 8.82 %, which were exploited for the fluorescence sensing of p -NP with 4.20 μM limit of detection. Pyrolyzed biochar acting as an efficient catalyst effectively reduces p -NP to p -aminophenol (p -AP) in just 16 min with a 0.237 min−1 rate of conversion. Furthermore, the produced p -AP was converted into paracetamol, an analgesic and antipyretic drug, to achieve zero waste theory. Thus, this study provides the execution of sustainable approaches based on the integral valorization of biowaste that can be further recycled and reused, offering an effective way to attain a profitable circular economy. [Display omitted] • Value-added carbon nanomaterials were synthesized from waste pea peels. • Blue fluorescent carbon dots act as a fluorescent sensor for p -nitrophenol (p -NP). • Solid biochar serves as a promising catalyst for the efficient reduction of p -NP. • The obtained p -aminophenol was further converted into a valuable drug, paracetamol. [ABSTRACT FROM AUTHOR]

Acacia Senegal waste (ASW) is remaining biomass following gum Arabic harvesting and has no use mentioned in the literature as of yet. This study aims to convert ASW into valuable biochar via two comparative thermal and hydrothermal techniques, which include pyrochar ASW at 300 °C (PC ASW300) and hydrochar ASW at 180 °C (HC ASW180), respectively, for Cu (II) adsorption from aqueous solutions. SEM-EDS, FTIR, XRD, and XPS were used to characterize the biochar. Adsorption performance was studied as a function of pH, contact time, and adsorbent concentration. Adsorption kinetics were best fit for a pseudo-second-order model. And thermodynamics studies revealed that Cu (II) on biochar was endothermic, spontaneous, and best fitted to the Langmuir isotherm model. Pyrochar adsorption capacity (31.93 mg g−1) was seven times that of hydrochar (5.45 mg g−1). ASW treated with phosphorus (PC H 3 PO 4 and HC H 3 PO 4) prior to the carbonization altered the pore structure and surface functional groups as well (O–P–O, P–CH 3 , and P–OH) of biochar. It was found that treating with phosphorous acid increased adsorption capacity to 141.7 mg g−1 and 22.24 mg g−1 for PC H 3 PO 4 and HC H 3 PO 4 , respectively. The surface functional groups of biochar resulted from lignin, alkaloids, and polysaccharides combined with Cu (II) during the adsorption process via surface complexation accompanied by π-electron interaction and Cu (II) reduction. These findings shed light on the ASW biochar potential as a new green cost-effective adsorbent and drew an insightful understanding of Cu (II) adsorption performance and mechanism. It is concluded that ASW-derived biochar is highly effective and a promising alternative for Cu (II) decontamination from wastewater. [Display omitted] • Acacia Senegal waste biochar has a potential as Cu(II) cost-effective adsorbents. • Phosphorous activated biochar grew Cu(II) adsorption capacity up to five times. • Copper adsorption on surface of biochar was accompanied by Cu(II) reduction. • Surface complexation and π electron interaction played a key role on adsorption. • Pyrochar show greater adsorption capacity and removal efficiency than hydrochar. [ABSTRACT FROM AUTHOR]

This study investigated the catalytic activity of biochar materials derived from algal biomass Sargassum fusiforme (S. fusiforme) for groundwater remediation. A facile single-step pyrolysis process was used to prepare S. fusiforme biochar (SFBC X), where x denotes pyrolysis temperatures (600 °C-900 °C). The surface characterization revealed that SFBC 800 possesses intrinsic N and P heteroatoms. The optimum experimental condition for acetaminophen (AAP) degradation (>98.70%) was achieved in 60 min using 1.0 mM peroxymonosulfate (PMS), 100 mg L−1 SFBC 800 , and pH 5.8 (unadjusted). Moreover, the degradation rate constant (k) was evaluated by the pseudo-first-order kinetic model. The maximum degradation (>98.70%) of AAP was achieved within 60 min of oxidation. Subsequently, the k value was calculated to be 6.7 × 10−2 min−1. The scavenger tests showed that radical and nonradical processes are involved in the SFBC 800 /PMS system. Moreover, the formation of reactive oxygen species (ROS) in the SFBC 800 /PMS system was confirmed using electron spin resonance (ESR) spectroscopy. Intriguingly, both radical (O 2 •−, •OH, and SO 4 •−) and nonradical (1O 2) ROS were formed in the SFBC 800 /PMS system. In addition, electrochemical studies were conducted to verify the electron transfer process of the nonradical mechanism in the SFBC 800 /PMS system. The scavenger and electron spin resonance (ESR) spectroscopy showed that singlet oxygen (1O 2) is the predominant component in AAP degradation. Under optimal condition, the SFBC 800 /PMS system reached ∼81% mineralization of AAP within 5 min and continued to ∼85% achieved over 60 min of oxidation. Coexisting ions and different aqueous matrices were investigated to examine the feasibility of the catalyst system, and the SFBC 800 /PMS system was found to be effective in the remediation of AAP-contaminated groundwater, river water, and effluent water obtained from wastewater treatment plants. Moreover, the SFBC 800 -activated PMS system demonstrated reusability. Our findings indicate that the SFBC 800 catalyst has excellent catalytic activity for AAP degradation in aquatic environments. [Display omitted] • PMS-activated Sargassum fusiforme biochar (SFBC 800) boosts acetaminophen breakdown. • Inherent N and P in SFBC 800 enhance the AAP degradation pathway. • Singlet oxygen (1O 2) is the dominant component in the SFBC 800 /PMS system. • SFBC 800 demonstrated reusability in groundwater, surface water, and wastewater. [ABSTRACT FROM AUTHOR]