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[Display omitted] • Low lignin content in algae makes thermochemical conversion to chars cost-effective. • Slow pyrolysis and HTC are preferred methods for algal char production. • Higher porosity and more diverse functional groups boost algal sorbent properties. • Enriched ash content in algal chars leads to higher cation exchange properties. • Modification of algal char enhances biosorbent properties. Biochar and hydrochar are carbon-rich solid products of algal and terrestrial biomass obtained through various thermochemical processes, mainly hydrothermal liquefaction, pyrolysis, and hydrothermal carbonization. Both are regarded as economical, potent, and environmentally friendly adsorbents for wastewater remediation. The versatile applicability of biochar and hydrochar, which is due to their enhanced surface physicochemical properties, includes efficient metal biosorption, soil fertility enhancement, and carbon sequestration. Consequently, there has been an increase in research for producing and exploiting biochar and hydrochar from algae. Both micro- and macro-algal biomass have strong potential due to their sustainability footprint and distinct properties. This review focuses on a comprehensive account of the synthesis of algal biochar and hydrochar and use in wastewater treatment to develop innovative solutions for efficient mitigation of several aqueous pollutants and heavy metal ions. The review discusses the various thermochemical production routes, biophysical characterization techniques, and modes of mechanism for wastewater bioremediation. Algal-based biochar and hydrochar are reported to have higher porosity and more diverse functional groups such as amines, hydroxyl, and carboxyl compared to their cellulosic and waste-derived counterparts, demonstrating an increased wastewater remediation efficiency. In addition, presence of inorganic metal including sodium, potassium, magnesium, and phosphorus in algal chars facilitates the formation of mesopores and graphite structures, improving their cation exchange capacity. Moreover, algal chars may exhibit pH buffering capacity, which could help stabilize the pH during wastewater treatment processes. Notably, the low O/C content of algal hydrochars enhances the binding and removal of organic pollutants including toxic dyes and antibiotics. The review highlights the development of modified algal chars to enhance the porosity, surface area, structural integrity, and adsorption capacity enabling a higher bioremediation potential. [ABSTRACT FROM AUTHOR]

This study presents the fabrication of rosette-shaped bismuth oxybromide/biochar (BiOBr/BC) photocatalysts supported on biochar via a straightforward solvothermal approach. This BiOBr/BC photocatalyst demonstrates remarkable efficiency in degrading 17α-ethinylestradiol (EE2). The incorporation of the photosensitizer Rhodamine B (RhB) significantly enhances the degradation rate of EE2, while RhB itself undergoes degradation during visible-light photocatalysis. Biochar serves as a substrate, offering several advantages such as improved adsorption, facilitated electron transfer, and increased production of free radicals, all contributing to the enhanced degradation of EE2 by BiOBr/BC. Under 20 min of visible light irradiation, the degradation rate of EE2 by the RhB-sensitized BiOBr/BC system reaches 99.28%. Furthermore, the incorporation of RhB improves the stability and recyclability of the BiOBr/BC system, maintaining an EE2 degradation rate of 92.00% after seven consecutive degradation cycles. Our photocatalytic system exhibits strong degradation activity towards a mixed-pollutant solution of EE2 and various dyes. LC-MS analysis identified the degradation products and computational predictions indicated their lower ecotoxicity compared to the parent compound. Overall, this study provides new insights and possibilities for the treatment of environmental pollutants, leveraging the concept of "curing waste with waste". [Display omitted] • Synthesized BiOBr/BC with high EE2 photocatalytic degradation activity. • Dual identity of RhB photosensitizer and contaminant. • BiOBr/BC can degrade the coexistence solution of mixed dyes and EE2. • Reduced the overall toxicity of the wastewater containing EE2. [ABSTRACT FROM AUTHOR]

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

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

[Display omitted] • Biochar modified with polysaccharide has more functional groups and active structures. • Different polysaccharide modifications produce different effects on biochar. • Remediation of pollutants in the environment through multiple mechanisms. • Polysaccharide-modified biochar has promising applications in real-world environments. • Polysaccharide-modified biochar meets the concept of green chemistry. With the rapid development of industry and agriculture, global environmental problems are becoming more and more serious. It is urgent for us to find green solutions to improve the environment. Biochar is a potentially cost-effective carbonaceous resource with a wide range of applications in agriculture and the environment. Modification of pristine biochar can further improve its performance in the target application. Polysaccharides-modified biochar are receiving increasing attention as a promising material for environmental treatment because they can combine the advantages of polysaccharides and biochar. In this paper, the differences and preparation methods of different polysaccharide-modified biochar, as well as the effects and mechanisms of polysaccharide-modified biochar in removing organic and inorganic pollutants from the environment were systematically discussed for the first time by critically analyzing the existing studies. In addition, the recycling capacity and methods of this type of modified biochar, and the current applications and effects in the real environment were also fully summarized and discussed. The future development of polysaccharide-modified biochar should focus on its recycling methods and costs as well as more in-depth exploration of its application in real environments. It is believed that this material can achieve good results in the field of environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar-based atomic Fe catalyst was prepared via co-pyrolysis strategy. • Fe-pyridinic N 4 was obtained by co-pyrolyzing biochar and SOFs with Fe-N 3 moiety. • Fe-MCA@SS/PMS system could effectively remove 94.5 % aniline within 5 min. • Mediated electron transfer via [Fe-N 4 /PMS]* mainly accounted for aniline removal. Pollution of groundwater by electron-rich refractory organic pollutants (e-ROPs) is detrimental to ecological integrity and human health. Biochar (BC)-based single-atom Fe catalysts (Fe–SACs) triggering nonradical peroxymonosulfate (PMS) process has shown great potential in addressing this problem. Nevertheless, the successful formation and precise regulation of active sites on BC remain formidable challenges. Herein, co-pyrolysis of BC derived from shrimp shells and N-containing supramolecular organic frameworks with a hexagonal cavity structure of Fe3+–N 3 (Fe–SOFs) was, for the first time, used to prepare an efficient and inexpensive BC-based Fe–SAC (Fe–MCA@SS). The Fe–N bond was successfully grafted from Fe–SOFs onto BC and subsequently transformed into monoatomic Fe–pyridinic N 4. Moreover, Fe–MCA@SS successfully triggered an efficient nonradical PMS process, degrading 94.5 % of aniline (AN) within 5 min. Mediated electron transfer (MET) mechanism was primarily responsible for AN removal. MET was attributed to the following factors: the synergistic effect of the stronger chemical adsorption of PMS with an Fe atom in Fe–pyridinic N 4 active sites, the higher redox potential of [Fe–MCA@SS/PMS]*, and the value of the lowest unoccupied molecular orbital of AN being larger than the value of highest occupied molecular orbital of [Fe–MCA@SS/PMS]*. This study sheds new light on the preparation of BC-based SACs catalyst with efficient nonradical oxidation ability and an excellent feasibility to remove electron-rich organic pollutants in groundwater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Use low-cost, readily available carbon sources. • The adsorption capacity of subjectively regulated biochar was 8.06 times higher than that of unactivated. • CoFe 2 O 4 @PBC 1.0 catalyst efficiently activated PMS, 20 mg/L of BPA was completely degraded in 30 min. • Suitable for a wide pH range (3-11) and degrades 100% of BPA in only 9 min at pH=11. • High concentration (200 mM) anionic environment hardly inhibits the degradation of BPA. • In liquid flow device, the degradation efficiency is still 80% at 40 h. Multiphase catalysts with wide pH, high environmental adaptability, and high activity are urgently needed for the water's contaminants to break down. In this study, the biomass waste bamboo leaves were used as the carbon source and activated by KOH to further increase the active sites (the adsorption capacity was 8.06 times that of the unactivated material) loaded with cobalt ferrite composite catalyst CoFe 2 O 4 @PBC X , which could effectively activate the PMS to realize the degradation of BPA. The CoFe 2 O 4 @PBC X + PMS system demonstrated remarkable BPA degradation across a broad starting pH range (3–11), and 100% BPA removal was achieved in 9 min at pH=11. CoFe 2 O 4 @PBC X achieved excellent BPA removal performance under high salinity conditions (200 mM). The toxicity of BPA and its oxidation intermediates was predicted by the ECOSAR model, which proved that BPA was eventually degraded into non-toxic products. In the bisphenol A degradation device, no catalyst deactivation was observed after 14 h, and 80% removal was maintained after 40 h. This study showed that the synthesized CoFe 2 O 4 @PBC X is a highly efficient PMS activation catalyst, which has the potential of low cost, high efficiency, and ecological friendliness in practical wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Column studies achieved 24.9 and 24.6 mg/g of adsorption capacities for Pb(II) and Cd(II) • The fixed bed mode attained 24 and 24.3 mg/g of adsorption capacity for Red198 and Blue29. • The Thomas model exhibited a strong correlation with the experimental data. • The Adams-Bohart model effectively described the initial phase of the C e /C 0 < 0.1. • After the 1st regeneration, 97% recovery of target pollutants was attained. • An increasing bed depth extended the operational lifespan of the column study. The adsorption behavior of Cd(II) and Pb(II) ions in a coexisting environment, alongside with both dyes (Reactive Red198 and Blue29) was systematically investigated by using a continuous fixed-bed column completely packed with Rosa damascena waste biosorbent (RDWB). Artificial neural network (ANN) model was also utilized to predict the performance of RDWB for various inputs. Their column performance was assessed by optimizing parameters such as bed depth, influent flow rate, and biosorbents' concentration. It was found that an increasing bed depth considerably extended the operational lifespan and decrease in flow rate delays the column adsorption. Its adsorption capacities were 24.9, 24.6, 24.0 and 24.3 mg/g for Pb(II), Cd(II), Red198, and Blue29, respectively. The RDWB also had a higher adsorption capacity, as compared to previously used biosorbents such as chitosan and biochars due to its good thermal stability and high surface area of 421.46 m2/g. The adsorption of target pollutants took place through ion exchange and electrostatic interactions with negatively charged functional groups on the adsorbent's surface. The experimental data were fitted by various column adsorption models such as the Thomas, Yoon-Nelson, and Adams-Bohart. The findings showed that the Thomas model exhibited a strong correlation with the experimental data. In contrast, the Adams-Bohart model was applicable to the initial phase of the breakthrough curve (C e / C 0 ≤ 0.1). For industrial applications, a scale up model was also presented with the cost analysis of the biosorbent. The comparison of predicted values with experimental percentage (%) removal values of target pollutants by the RDWB indicated the excellent performance of the ANN model for this work. [ABSTRACT FROM AUTHOR]

Biochar is a carbon-rich material produced from the partial combustion of different biomass residues. It can be used as a promising material for adsorbing pollutants from soil and water and promoting environmental sustainability. Extensive research has been conducted on biochars prepared from different feedstocks used for pollutant removal. However, a comprehensive review of biochar derived from non-woody feedstocks (NWF) and its physiochemical attributes, adsorption capacities, and performance in removing heavy metals, antibiotics, and organic pollutants from water systems needs to be included. This review revealed that the biochars derived from NWF and their adsorption efficiency varied greatly according to pyrolysis temperatures. However, biochars (NWF) pyrolyzed at higher temperatures (400–800 °C) manifested excellent physiochemical and structural attributes as well as significant removal effectiveness against antibiotics, heavy metals, and organic compounds from contaminated water. This review further highlighted why biochars prepared from NWF are most valuable/beneficial for water treatment. What preparatory conditions (pyrolysis temperature, residence time, heating rate, and gas flow rate) are necessary to design a desirable biochar containing superior physiochemical and structural properties, and adsorption efficiency for aquatic pollutants? The findings of this review will provide new research directions in the field of water decontamination through the application of NWF-derived adsorbents. [Display omitted] • Non-woody feedstock-derived biochar removes pollutants from the water system. • Higher-temperature pyrolyzed biochar has excellent physicochemical attributes. • The derived biochar is rich in ash and nutrient contents. • The derived biochar has a higher surface area, porosity, and carbon contents. • Functional groups are key active sites for eliminating pollutants from the water system. [ABSTRACT FROM AUTHOR]

This study critically appraises employing chitosan as a composite with bentonite, biochar, or both materials as an alternative to conventional barrier materials. A comprehensive literature review was conducted to identify the studies reporting chitosan-bentonite composite (CBC), chitosan amended biochar (CAB), and chitosan-bentonite-biochar composite (CBBC) for effective removal of various contaminants. The study aims to review the synthesis of these composites, identify fundamental properties affecting their adsorption capacities, and examine how these properties affect or enhance the removal abilities of other materials within the composite. Notably, CBC composites have the advantage of adsorbing both cationic and anionic species, such as heavy metals and dyes, due to the cationic nature of chitosan and the anionic nature of montmorillonite, along with the increased accessible surface area due to the clay. CAB composites have the unique advantage of being low-cost sorbents with high specific surface area, affinity for a wide range of contaminants owing to the high surface area and microporosity of biochar, and abundant available functional groups from the chitosan. Limited studies have reported the utilization of CBBC composites to remove various contaminants. These composites can be prepared by combining the steps employed in preparing CBC and CAB composites. They can benefit from the favorable adsorption properties of all three materials while also satisfying the mechanical requirements of a barrier material. This study serves as a knowledge base for future research to develop novel composite barrier materials by incorporating chitosan and biochar as amendments to bentonite. [Display omitted] • Chitosan with highly reactive functional groups is effective for contaminant removal. • Bentonite is a desirable composite constituent for contaminant removal due to its surface area and anionic nature. • Biochar in the composite increases surface area for contaminant adsorption. • Composite synthesis procedures vary depending on the application. • Contaminant removal by composites varied widely due to the variability in materials. [ABSTRACT FROM AUTHOR]

Semiconductor titanium dioxide (TiO 2) has garnered significant attention in photocatalysis field, but the wide bandgap and fast recombination of photogenerated electron-hole pairs severely hamper its extensive application. Herein, we present a novel biomass-assisted strategy to construct S-scheme heterojunction tin quantum dots-modified titanium dioxide@nitrogen, oxygen-containing biochar composite photocatalyst (Sn QDs/TiO 2 @biochar). The influence of pyrolysis temperature, biomass amount, and Sn content on adsorptive and UV-/Vis-photocatalytic performance of Sn QDs/TiO 2 @biochar were systematically optimized. The optimally-prepared catalyst displays a full light absorptive response feature and improved adsorptive and UV-/Vis-photocatalytic performance in the removal of high concentration methylene dye and tetracycline hydrochloride. The excellent performance of Sn QDs/TiO 2 @biochar is attributed to the enhanced synergic effects among many factors, such as multi-functions of each component, series size quantum effects of Sn QDs, heterojunctions, especially S-scheme heterojunction between Sn QDs and TiO 2. Furthermore, a plausible photocatalytic mechanism was proposed. This study may provide a simple and sustainable approach for constructing environmentally friendly, cost-effective, and high-performance photocatalysts. [Display omitted] • S-scheme heterojunction within Sn QDs/TiO 2 @biochar was constructed by biomass-assisted strategy. • Sn QDs/TiO 2 @biochar shows excellent adsorptive and UV-/Vis-photocatalytic performance for removing organic pollutants. • Excellent performance is attributed to synergic effects including quantum size of Sn QDs and IEF of S-heterojunction. • Full light absorption spectrum of Sn QDs/TiO 2 @biochar is mainly ascribed to Sn QDs and biochar. • Preparation method is simple, efficient, cost-effective, environmental-friendly, and waste resources are reutilized. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel biocatalyst BFMO@BC was successfully synthesized. • 1O 2 was evidenced as the dominant reactive oxidizing species. • BFMO@BC was environmentally adaptable and exhibited excellent cycling properties. • The bimetallic cycle, C=O groups, and carbon defects were responsible for the superior catalytic activity. Biogenic metal oxides are considered superior eco-friendly candidates for peroxymonosulfate (PMS) activation. However, they often suffer from metal aggregation, high ion leaching, and poor recyclability, diminishing their practical attractiveness. In this study a novel biochar-loaded biogenic iron-manganese oxide composite (BFMO@BC) was synthesized to activate PMS for sulfamethoxazole (SMX) degradation. The introduction of biochar brought more active sites (C=O and carbon degree), promoted the bimetallic redox cycle between Fe and Mn, and facilitated the conversion of SO 5 •− to 1O 2 , which significantly improved the catalytic performance. Results demonstrated 100 % SMX degradation within 3 min in BFMO@BC/PMS system. And the reaction rate constant of this system was as high as 0.852 min−1, which was 11.6 times than that of BFMO/PMS. Moreover, high SMX removal efficiencies (near 100 %) could be obtained over a wide pH range (3–11) and in complex water matrices. BFMO@BC displayed excellent adaptability, stability, and reusability for SMX removal. This study provides new insights into the utilization of biocatalysts in advanced oxidation processes for pollutant degradation. [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]

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]

As of now, submerged plants and biochar have demonstrated significant benefits in aquaculture pond sediment remediation. However, there is limited research on the synergistic effects of biochar and submerged plants in mitigating hydrophobic organic contaminant (HOC) accumulation in aquaculture benthic organisms and in controlling the nutrient (nitrogen and phosphorus) levels in aquaculture water. This study assesses a submerged plant-biochar system's efficacy in removing HOCs from simulated freshwater aquaculture ponds. Vallisneria natans was planted in sediment with varying levels of wheat straw biochar, while Corbicula fluminea served as the targeted benthic organism. The bioaccumulation experiment identified the optimal biochar ratio for the Vallisneria natans -biochar system in controlling HOCs in aquaculture products. Analyses included final accumulation concentrations in benthic organisms, changes in freely-dissolved concentrations in aquaculture sediment, and a mass balance calculation to explore key factors in their removal from the system. Results indicated that the Vallisneria natans -1.5% biochar composite system achieved optimal control of HOCs in sediment and aquaculture products. Biochar addition to the sediment in the composite system demonstrated a "promotion with low addition, inhibition with high addition" effect on Vallisneria natans growth. Notably, the addition of 1.5% biochar (VN1.5 group) significantly promoted the growth of Vallisneria natans leaves and roots. Comparing the final pollutant proportions in different environmental media, concentrations in water (0.20%–1.8%), clam accumulation (0.032%–0.11%), and plant absorption (0.10%–0.44%) constituted a minimal portion of the overall pollutant load in the system. The majority of pollutants (24%–65%) were degraded in the aquaculture environment, with microbial degradation likely playing a predominant role. Bacterial phyla, particularly Proteobacteria and Firmicutes, were identified as potential direct contributors to pollutant degradation in the Vallisneria natans -biochar system. [Display omitted] • Biochar, in synergy with submerged plants, further reduced HOC accumulation by >40%. • Vallisneria natans-1.5% biochar system removed >70% TN/TP in water. • A major role of microbial degradation was clear as 24%–65% of HOCs was degraded. • Proteobacteria increased by 11% in abundance, potentially key in HOC degradation. [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]

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]

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]

[Display omitted] • The floating biochar accelerated the immobilized FeCo PBA to absorb sunlight. • The substrate biochar facilitated photogenerated electron transfer of FeCo PBA. • The immobilization enhanced the stability of FeCo PBA in water. • Possible pathway of CQ degradation was proposed based on nine identified products. Fe-Co Prussian blue analogue (PBA) nanospheres were immobilized on biochar (PBA-on-biochar) to remove contaminants via photo-Fenton process. The loading weight of FeCo PBA on biochar increased with increasing PBA aging temperature and time. The PBA exhibited efficient chloroquine phosphate (CQ) degradation under both LED light and sunlight, where OH and 1O 2 dominated the oxidation. The CQ degradation was slightly affected by pH value (3.5–9.5) and co-existing anions like SO 4 2−, Cl− and NO 3 –. The application potential of the PBA-on-biochar was evaluated in a continuous reaction device. Theoretical calculation revealed the dominant role of Fe sites in PBA for H 2 O 2 activation. The degradation pathway was proposed based on nine intermediate products. Also, the excellent photo-Fenton activity and good floatability enable PBA-on-biochar to be efficient in inhibiting the activity of Microcystis aeruginosa under sunlight. The results implied that PBA-on-biochar is applicable for fast micropollutant oxidation from water. [ABSTRACT FROM AUTHOR]

The co-transport behavior of environmental pollutants with biochar particles has aroused great interests from researchers due to the concerns about pollutant diffusion and environmental exposure after biochar is applied to soil. In this work, the recovery and co-transport behavior of biochar micron-/nano-particles (BCMP and BCNP) and lead (Pb2+) in saturated porous media were investigated under different ionic strength conditions (IS = 1, 5 and 10 mM) under a direct current electric field. The results showed that the electric field could significantly enhance the mobility of Pb adsorbed biochar particles, particularly BCNP. The recovery of Pb laden biochar particles was improved by 1.8 folds, reaching 78.8% at maximum under favorable condition at +0.5 V cm−1. According to the CDE (Convection-Dispersion-Equation) model and DLVO (Derjaguin-Landau-Verwey-Overbeek) theory analysis, the electric field facilitated the transport of Pb carried biochar mainly by increasing the negative charges on biochar surface and improving the repulsive force between biochar and porous media. High IS was favorable for biochar transport under the electric field, but inhibited desorbing Pb2+ from biochar (18% by maximum at IS = 10 mM). By switching the electric field power, a two-stage strategy was established to maximize the recovery of both biochar particles and Pb, where BCNP and Pb recovery were higher than electric field free case by 90% and 35%, respectively. The findings of this study can help build a biochar recovery approach to prevent potential risks from biochar application in heavy metal contaminated soil remediation. [Display omitted] • Electric field promoted the migration of both Pb laden/free biochar particles. • Up to 78.8% of Pb2+ laden biochar nano-particles recovered under 0.5 V·cm-1. • Electric field detach about 18% adsorbed Pb from biochar under high ionic strength. • Two-stage strategy were proposed to recover both biochar and Pb2+. [ABSTRACT FROM AUTHOR]

Soil salinization is a major environmental hazard that limits land availability. Human-induced salt pollutants (HISPs) are regularly presented in large quantities on the contaminated site (such as brine leakages and salt-water spills), causing a devastating shock with high salt stress to the ecosystem. For instance, Saskatchewan resulted in a 48% drop in wheat production and a 0.3% decline in provincial GDP. As the calcium-modified biochar can potentially ameliorate the negative effects of HISPs on plants and improve the plant, phytoremediation with calcium-modified biochar can have increased detoxification of hazardous pollutants from sites. Therefore, the objective of our study was to develop a biochar-assisted phytoremediation employing diverse approaches to calcium modification for the sustainable removal of HISPs. The co-pyrolyzed calcium biochar achieved a remarkable removal rate of 18.06%, reducing salinity from 9.44 to 7.81 dS/m. During a 90-day long-term phytoremediation, the overall reduction rate of calcium-modified biochar stimulated the germination and growth of Thinopyrum ponticum. The result of post-treatment further indicated that co-pyrolyzed biochar with Ca transferred salt into the plant compared to Ca-coated biochar, which only immobilized HISPs on its surface. These results offer two different treatment approaches for diverse situations involving HISPs contamination, addressing current in-situ spills and providing a calcium-related biochar technology for further research in desalination. [Display omitted] • Ca-coated and Ca-copyrolyzed biochar for phytoremediation of saline soil were investigated. • Ca-modified biochars generated from copyrolysis and coating. • Ca-modified biochars displayed enhanced capability in direct removing salt from brine water • In a 90-day phytoremediation, Ca-modified biochar reduced salinity and improved soil quality • Ca-copyrolyzed and Ca-coated biochar have diverse roles in salt migration into vegetations [ABSTRACT FROM AUTHOR]

In this study, a novel Fe 3 O 4 -based biochar coupled surface-imprinted polymer was constructed via simple hydrothermal route for salicylic acid recognition and degradation in advanced oxidation processes. The material exhibited excellent adsorption capability, up to 118.23 mg g−1, and efficient degradation performance, 87.44% removal rate within 240 min, based on integrating the advantages of both huge specific surface area as well as abundant functional groups from biochars and specific recognition sites from imprinted cavities. Moreover, high selectivity coefficient (11.67) showed stable recognition in single and binary systems. SO 4 •− and •OH were confirmed as reactive oxygen species in catalytic reaction according to quenching experiments and EPR analysis. The degradation mechanism and pathway were unraveled by DFT calculations and LC-MS. Furthermore, the results of toxicity evaluation, stability and reusability demonstrated application potential in the field of water environment restoration. This study confirmed that molecular imprinting provided a promising solution to targeted removal of emerging environmental pollutants by degrading after the enrichment of pollutants to the composites surface. [Display omitted] • A novel molecularly imprinted polymers coated Fe 3 O 4 -BC was successfully synthesized. • Adsorption-degradation activities and specific recognition of SA by MI-FBC were improved. • MI-FBC exhibited good stability and regenerability with tolerance to wide pH and anions. • The mechanism and pathway of SA removal were proposed based on experiments and DFT calculations. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel biochar (CHKBC) co-modified with KOH and chitosan was synthesized. • KOH activation significantly increased the loading of chitosan on biochar surface. • CHKBC showed strong adsorption for methylene blue in various environments. • Adsorption mechanisms were revealed by various characterization methods. The treatment of dye pollutants remains a challenge in the current management of the water environment. In this study, an innovative biochar material co-modified with KOH and chitosan was synthesized. The morphology and physicochemical properties of the modified biochar material were assessed by SEM, FTIR, XPS, XRD, and thermogravimetric analyses. The results revealed a significant enhancement in chitosan loading due to the pretreatment of biochar with KOH. The co-modified biochar with KOH and chitosan (CHKBC) exhibited an enriched composition of functional groups such as − COOH, −NH 2 , and − OH, leading to a substantial increase in the maximum adsorption of MB by the biochar from 8.83 mg g−1 to 62.04 mg g−1, a 7.03-fold increase. The excellent adsorption performance of CHKBC for MB was maintained at different solution temperature (288–––318 K) and pH (5–––11) conditions. The main adsorption mechanisms of MB removal by CHKBC involved ion exchange, pore filling, electrostatic attraction, π - π interactions, and hydrogen bonding. Overall, CHKBC has higher chitosan loading, more uniform chitosan distribution, and better adsorption efficiency of MB. It is a promising adsorption material with low cost and a simple production process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption capacity of BC on MG is about 30 and 60 times that of SY and ENR. • The molecular mechanism of BC on MG was analyzed using statistical physical models. • Adsorption advantages are a combination of mesopore structure and high ash content. • The mesoporous structure provides adsorption space for multimolecular aggregates. • The ionic polarity sites in the ash are the main active sites for adsorption on BC. Adsorption is considered to be one of the most promising methods for treating organic wastewater. This paper focuses on the adsorption characteristics and molecular mechanisms of ionic organic pollutants (IOPs) on bone char (BC). It was found that BC had excellent adsorption performances for cationic organic pollutants with large molecular, especially malachite green (MG, triphenylmethane): the maximum adsorption capacity is 1.3–1.5 and 5.6–6.9 times higher than that of straw biochar (SBC) and activated carbon (AC), respectively, and 30 and 60 times higher than that of anionic and amphoteric organic pollutants. The adsorption mechanism of IOPs on BC was analyzed at the macroscopic level by comparing the differences in the physicochemical properties of the adsorbents and the changes before and after adsorption. Then, statistical physical modeling was used to investigate the mechanism of interaction between BC and IOPs at the molecular scale (mesoscopic level). The results showed that the rich mesoporous structure and ionic polarity sites of BC play an essential role in the adsorption of MG. PO 4 3-, CO 3 2–, and OH– are the effective sites for adsorption of BC, with the density of sites significantly higher than that of SBC and AC. It can be surmised that BC adsorbs the IOPs through pore filling and electrostatic interactions. Techno-economic analysis showed that the adsorption cost of BC could be reduced by 37.89% to 81.72% compared with modified biochar and commercial AC, indicating that BC has wide application prospects and market competitiveness. The results of this study can provide vital theoretical support for the practical application of BC. [ABSTRACT FROM AUTHOR]

Biochar-based single-atom catalyst with atomically dispersed FeN 5 sites (Fe-N-FPBC) is rationally prepared through a micropores construction-functionalization-N doping cascade regulation strategy. The as-synthesized Fe-N-FPBC is rich in micropores and defects which are crucial for effective N doping to achieve FeN 5 sites. The electron transfer mediated by Fe-N-FPBC contributes to the ultra-fast degradation of sulfamethoxazole via peroxymonosulfate activation. The catalyst-dosage-normalized kinetic constant is 52.63 L min−1 g−1, outdistancing reported values. Density-Functional-Theory calculations reveal that the FeN 5 site exhibits favorable global energy compared to FeN 4 site. The axial ligand of FeN 5 site results in thermodynamically facilitated electron extraction from contaminants, and also leads to the easier desorption of -SO 4 H for rapid site regeneration. Overall, this work provides a pathway for the fabrication of biochar-based single-atom catalyst with high metal-N coordination number for efficient Fenton-like catalysis. [Display omitted] • Cascade regulation strategy is proposed for construction of FeN 5 sites on biochar. • Micropores and defect help to increase N coordination number of single Fe atom. • The normalized kinetic rate constant of 52.63 L min−1 g−1 exceeds reported values. • Catalyst-mediated direct electron transfer dominates the pollutant degradation. • Low-energy-barrier regeneration of FeN 5 sites contributes to efficient catalysis. [ABSTRACT FROM AUTHOR]

The disposal of coffee shell waste on farmland, is a common practice that can causing the environmental and waste valuable resources. Carbonization has been identified as an effective method for transforming coffee shells into useful products that mitigate environmental pollution. Through the response surface methodology, the carbonization conditions of the coffee shells were optimized and its potential as a biochar-based slow-release urea fertilizer was explored. Experiments were conducted on coffee shell performance under varying carbonization conditions such as temperature (600–1000 °C), time (1–5 h), and heating rate (5–20 °C/min). The results indicated that the ideal urea adsorption was 56.3 mg/g, achieved under carbonization conditions of 2.83 h, 809 °C, and 15.3 °C/min. The optimal nutrient release rate within seven days was 45.4% under carbonization conditions of 3.19 h, 813 °C, and 15.0 °C/min. The infrared spectroscopy analysis indicates that carbonization conditions influenced the absorption peak intensity of coffee shell biochar, while the functional group types remain unchanged. The biochar exhibits diverse functional groups and abundant pores, making it a promising candidate for use as a biochar-based fertilizer material. Overall, the findings demonstrate an effective waste management approach that significantly reduces environmental pollutants while remediating pollution. • Carbonization can reduce coffee shell pollution and utilize waste reasonably. • The desirable properties of biochar was improved by optimizing the process. • The potential of coffee shell biochar for biochar-based fertilizers was explored. • Coffee shell biochar can contribute to sustainable development and circular economy. [ABSTRACT FROM AUTHOR]

This study investigates our hypothesis that how effect of arsenic stress on okra (Abelmoschus esculentus L.) can be alleviated through the use of waste materials such as steel slag (SS) and corncob biochar (BC). Different growth variables, biochemical parameters, oxidative stress markers, enzymatic and non-enzymatic antioxidants and glyoxylase enzyme activities were assessed. When okra was exposed to As, there was a noticeable decrease in seedling length, biomass, relative water content, various biochemical attributes, however, electrolyte leakage and lipid peroxidation in okra were enhanced. The supplementation of SS and BC—either individually or in combination—improved the growth parameters and reduced oxidative stress markers. Application of SS and BC also lowered As accumulation in roots and shoots of okra mitigating adverse effects of As exposure. Additionally, the activities of antioxidant and glyoxalase enzyme increased when SS and BC were present, concurrently reducing methylglyoxal content. Arsenic-induced stress led to oxidative damage, an enhancement in both enzymatic and non-enzymatic antioxidants, induced the synthesis of thiol and phytochelatins in roots and shoots. These may play a vital function in alleviating oxidative stress induced by As. Superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase activities were significantly enhanced in As-treated plants. These enhancement were further amplified when SS and BC were amended to As-treated okra. Therefore, synergistic application of SS and BC effectively protects okra against oxidative stress induced by As by increasing both antioxidant defense and glyoxalase systems. Both SS, an industrial byproduct, and BC, generated from agricultural waste, are cost-effective, environmentally friendly, safe, and non-toxic materials which can be used for crop production in As contaminated soil. [Display omitted] • Steel slag and corncob biochar enhanced growth of okra plants under arsenic stress. • ROS scavenging mechanism was strengthened by osmolytes accumulation. • Total acid soluble thiol and phytochelatin contents were enhanced in okra roots and shoots under arsenic stress. • Steel slag and corncob biochar declined arsenic-incited oxidative damage by boosting antioxidant and glyoxalase system. [ABSTRACT FROM AUTHOR]

The olive stone is a large waste product of the olive oil extraction industry. The present study investigates developing activated carbon from olive stone waste (OSAC) to remove pharmaceuticals from water. Different temperatures and olive stone: KOH ratios were studied. The OSAC produced at 750 °C and 1:3 ratio was found to have the highest porosity and surface area and was tested in the adsorption process. Diclofenac and ciprofloxacin were selected as model contaminants. The adsorption process was optimized with regards to OSAC dosage, pH, temperature, and initial concentration of adsorbate. The OSAC was found to be effective for a wide pH range (2–11) with an optimum dosage of 1 g/L at 25 °C. The pharmaceuticals were almost completely removed in 75 min. The adsorption was endothermic and followed first-order kinetics with physical mechanisms such as electrostatic possibly being the main driver. The optimum conditions were applied to test the removal of diclofenac and ciprofloxacin in synthetic water, lake water (Lake Balaton, Hungary) and secondary wastewater for seven cycles. There was little difference between the removal of the tested water matrices highlighting the potency of OSAC as an adsorbent for pharmaceutical removal in industrial applications. The removal dropped from >99% for the first cycle to 20–30% for the seventh cycle. [Display omitted] • Both diclofenac and ciprofloxacin were removed from different water matrices. • The long-term performance of derived fossil-free carbon was up to 7 cycles. • Optimum removal conditions were pH 7, 25 °C, 50 mg/L mixture and OSAC of 1.0 g/L. • Fast removal of the pollutant's mixture within olive stones waste by 75 min. [ABSTRACT FROM AUTHOR]

Azo dyes, the most common synthetic dyes used in the textile industry, are known xenobiotic compounds and recalcitrant to conventional degradation treatments. As consequence, such contaminants are often discharged into the effluents, treating aquatic ecosystems. Among several processes, the use of zero valent iron (ZVI) represents a suitable alternative to degrade organic molecules containing azo bonds. However, its applications are limited by corrosion and loss of reactivity over the time. To overcome these constraints, ZVI has been coupled to a suitable semiconductor (ZnS) to get a catalytic composite (ZVI-ZnS) active under UV light. The present work deals with the degradation of acid orange (AO7), used as model azo dye, by UV/ZVI-ZnS, as one step treatment and in combination with an adsorption process by biochar. The influence of ZVI-ZnS concentration (0.25, 0.5, 1 and 2 g/L) and reaction time (0–160 min) on degradation of AO7 were investigated. Intermediates formation was monitored by ESI-FT-ICR-MS analysis and the effluent toxicity was assessed by using Artemia franciscana. The experimental results showed that the UV/ZVI-ZnS process at 1 g/L of catalyst allowed to achieve a removal of AO7 up to 97% after 10 min. An increase of the dye relative concentrations as well as the toxicity related to intermediates formations has been observed for treatment time higher than 10 min. The total removal of AO7 together with effluent toxicity reduction was obtained only after the combined treatment (UV/ZVI-ZnS + biochar). [Display omitted] • A removal of AO7 up to 97% after 10 min was achieved by UV/ZVI-ZnS process. • Reaction intermediates were identified. • Dye relative concentrations increased for treatment time higher than 10 min. • Total removal of AO7 and toxicity was obtained after a combined treatment. [ABSTRACT FROM AUTHOR]

Spruce wood and Typha (wetland plant) derived biochars pyrolyzed at 350 °C and 600 °C were tested for their sorption affinity for organic pollutants (diclofenac, methylparaben, benzotriazole and sodium 1-decanesulfonate) and nutrients (nitrate, ammonium, phosphate and boron) commonly found in greywater. Batch and column studies combined with molecular dynamics modelling determined the sorption capacity, kinetics, and described the underlying mechanisms. The spruce biochar (600 °C) exhibited the highest sorption capacity mainly for the tested organics. The dynamic test performed for spruce biochar (600 °C) showed that the magnitude of desorption was low, and the desorbed amount ranged between 3 and 11 %. Molecular dynamics modelling (a computational tool for elucidating molecular-level interactions) indicated that the increased sorption of nitrate and boron on spruce biochar (600 °C) could be attributed to hydrophobic interactions. The molecular dynamics shows that predominant adsorption of organic pollutants was governed by π-π stacking, with a minor role of hydrogen-bonding on the biochar surface. In summary, higher pyrolysis temperature biochar yielded greater adsorption capacity greywater borne contaminants and the reaction temperature (10–34 °C) and presence of anionic surfactant had a limited effect on the adsorption of organic pollutants, suggesting efficacious application of biochar in general for greywater treatment in nature-based systems. [Display omitted] • Four biochars were produced from spruce and Typha at 350 °C and 600 °C. • Spruce biochar (600 °C) had the highest capacity for organics, phosphate and nitrate. • Reaction temperature (10–34 °C) and surfactants had low effect on the adsorption. • Molecular dynamics indicated π-π stacking mechanism to be predominant for organics. • Tested biochars (except Typha 350 °C) are good candidates for greywater treatment. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are critical environmental concerns due to their intrinsic toxic aromatic nature and concomitant circumstances that potentially harm the ecological and human health. In this study, converting mahogany (Swietenia macrophylla King) pericarps to value-added biochar by pyrolysis for evaluating the potential formation/destruction of biochar-bound PAHs was studied for the first time. This study designed and optimized the thermal processing conditions at 300–900 °C in the CO 2 or N 2 atmosphere, and heteroatoms (N, O, B, NB, and NS) were modified for mahogany pericarps biochar (MPBC) production. The MPBC500 exhibited significantly higher pyrolysis products of PAHs (2780 ± 38 ng g−1) than that of MPBC900 (78 ± 6 ng g−1) under N 2 without introducing modified elements. Specifically, the inhibition capacity of MPBC500 for PAHs under CO 2 was improved most efficiently by the active nitrogen species of the pyridinic N and pyrrolic N groups. The pyrolysis conditions and heteroatom modification of MPBC altered its physicochemical properties, that is, aromaticity and hydrophobicity, affecting the PAH concentration and composition in the pyrolysis products. This study reveals sustainable approaches to reduce the environmental footprint of biochar by focusing on increases in PAHs pollution in sustainable biochar produced from a low-carbon bioeconomy perspective. [Display omitted] • Biochar produced at 500 °C in the presence of CO 2 led to high polycyclic aromatic hydrocarbons yield. • Naphthalene was the dominant biochar-bound polycyclic aromatic hydrocarbon. • Pyrolysis in N 2 reduced the level of polycyclic aromatic hydrocarbons in unmodified biochar at 900 °C. • Doping with N effectively suppressed polycyclic aromatic hydrocarbons formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acid modification reduced HMs and extractable PAHs content the most effectively. • H 2 O 2 reduced extractable and bioavailable PAHs but was less effective than acid. • Base treatment significantly increased the extractable PAHs in most BCs. • Porosity and DOC determined contaminant changes in BC after H 2 O 2 or base treatment. The effect of biochars (BCs) chemical modifications on the content of various contaminants is poorly studied and understood, despite the fact that such results would be important in terms of estimating the safety of BCs application. The aim of this study was to evaluate the content of different types of contaminants - heavy metals (HMs), polycyclic aromatic hydrocarbons (solvent extractable - C tot and freely dissolved - C free PAHs) and environmentally persistent free radicals (EPFRs) in post-pyrolytic chemically modified (HNO 3 , KOH and H 2 O 2) BCs produced under diverse conditions (temperature and carrier gas) and from various feedstocks (willow, rice husk, sewage sludge, oil seed rape straw, wheat straw). The physio-chemical properties of BCs were determined (such as morphology, elemental composition and chemical state, and crystalline structure) and correlated with contaminants content. Regardless of the BCs type, acid modification reduced HMs and C tot PAHs the most effectively but simultaneously increased C free PAHs and EPFRs content (compared to pristine BCs). Changes in contaminant content after H 2 O 2 and alkali treatment were more varied and strictly related to the physio-chemical properties of BCs (such as porosity, DOC, and polarity). H 2 O 2 treatment reduced C tot and C free PAHs content but was less effective than acid modification. In contrast, KOH treatment significantly increased the C tot in most BCs, which depends mainly on porosity and DOC changes. Also, the reduction in HMs content and increase in EPFR after alkali and H 2 O 2 treatment were less substantial and more differentiated by BC origin than after acid modification. [ABSTRACT FROM AUTHOR]

Calcite-biochar composites are attractive materials with outstanding adsorption capabilities for removing various recalcitrant contaminants in wastewater treatment, however, the complexity of their synthesis limits their practical applications. In this work, we have prepared calcite-rich biochar (Ca-BC) from a single precursor (Tamarindus indica bark), which simplifies the synthetic route for preparing calcite-biochar composite. The as-synthesized composite is utilized to make a heterogeneous catalytic system containing the supported silver nanoparticles (Ag@Ca-BC) formed by the reduction of Ag+ ions on the surface of the composite. The formation of Ag@Ca-BC is confirmed by various characterization techniques such as PXRD, FT-IR, UV–Vis, cyclic voltammetry, impedance measurement, SEM, and TEM analyses. Especially, the TEM analysis confirms the presence of Ag nanoparticles with size ranging between 20 and 50 nm on the surface of Ca-BC composite. The nano-catalyst Ag@Ca-BC efficiently promotes the conversion of 4-nitrophenol to 4-aminophenol using NaBH 4 as the reductant in water within 24 minutes at room temperature, suggesting that Ag@Ca-BC can be an efficient catalyst to remove nitroaromatics from the industrial effluents. The straightforward synthesis of Ca-BC from a single precursor along with its utility as a catalytic support presents a compelling proposition for application in the field of materials synthesis, catalysis, and green chemistry. [Display omitted] • Valorisation of biomass debris into a valuable support material for catalysis. • Calcite-rich biochar preparation from a single source (Tamarindus Indica). • Reduction of Ag + ions over calcite-rich biochar yields a cost effective and energy efficient catalyst (Ag@Ca-BC). • Facile conversion of toxic 4-nitrophenol to useful 4-aminophenol over Ag@Ca-BC. • The observed k app value of 4.88 × 10−3 s−1 demonstrates the competitiveness of Ag@Ca-BC with most of reported Ag-based catalysts. [ABSTRACT FROM AUTHOR]

Eliminating different pharmaceutical contaminants simultaneously from wastewater has become a crucial environmental issue. In this regard, the shift from the conventional methods of removing single pollutant to implementing a system that simultaneously removes multiple contaminants is required. In pursuit of this goal, functionalized biochar (FBC) was prepared from bamboo sawdust to simultaneously remove pharmaceutical pollutants in batch and fixed-bed sorption systems. FBC exhibited a greater removal capacity for acetaminophen (ACM) (192.43 mg/g) compared to ciprofloxacin (CIP) (70.95 mg/g), as predicted by the Langmuir isotherm model. The competitive Langmuir isotherm model, employed for the binary component, predicted a maximum adsorption capacity of 125.31 mg/g for ACM and 65.44 mg/g for CIP. The adsorption capacity ratio (q m binary /q m single < 1) suggests an antagonistic behavior of these pollutants when they co-exist in the water matrix. On the other hand, the single and binary component adsorption of ACM and CIP was best described by pseudo-second-order kinetic model, indicating that the adsorption process was mainly controlled by the chemisorption process. Fixed-bed column study showcased the maximum bed capacity of ACM (172.48 mg/g) and CIP (147.67 mg/g), with the highest respective removal efficiency of 44.23% and 37.86% in the binary component adsorption system. However, the single-component column adsorption system achieved a higher removal efficiency of 65.83% (ACM) and 42.59% (CIP). These results indicate that the simultaneous removal of ACM and CIP depends on the unique molecular properties of ACM/CIP and their interactions with the adsorbent. Hence, the as-synthesized FBC has been proven effective for the simultaneous removal of ACM and CIP from various water matrices. [Display omitted] • Highly functionalized biochar (FBC) was prepared via dual chemical modification. • Rigorous batch and fixed-bed studies were provided for single and binary sorption. • Simultaneous sorption of ACM and CIP has antagonistic nature. • FBC exhibited uptake of 125.31 mg/g (ACM) and 65.44 mg/g (CIP) in binary sorption. • The synthesized biochar adsorbent was found to be effective on real water matrix. [ABSTRACT FROM AUTHOR]

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

• Raw BC and acid-modified BC can activate H 2 O 2 to generate OH to degrade CIP. • The BC-induced catalytic degradation by PFRs play a more important role. • sp2 C C, C O, pyridonic-N and pyridinic-N in BC are catalytic reactive sites. • Single-electron transfer from PFRs to H 2 O 2 is a possible activation mechanism. Biochar (BC) is usually applied in the remediation of contaminated water and soil as an excellent adsorbent, but recently, the BC-induced catalytic degradation of organic contaminants by persistent free radicals (PFRs) is attracting considerable attention. In this study, BC was prepared from the pyrolysis of sewage sludge and used to activate hydrogen peroxide (H 2 O 2) for the degradation of ciprofloxacin (CIP) in water. Results showed that the HNO 3 modified-BC exhibited better catalytic ability to activate H 2 O 2 than the raw BC. Under similar conditions: pH 7 and H 2 O 2 1.0 mmol/L, the removal efficiency of CIP by HNO 3 modified-BC/H 2 O 2 (93.00%) was obviously superior to that of BC/H 2 O 2 (70.60%). The calculated contributions of adsorption and degradation to CIP removal demonstrated that BC exhibited certain CIP adsorption ability, but the contributions of adsorption led by raw BC and HNO 3 modified-BC were only 38.31% and 29.81%, respectively. The proportion of catalytic oxidation induced by PFRs in BC accounted for 61.69% and 70.19%, suggesting the important role of PFRs in CIP removal. HNO 3 modification not only altered the surface characteristics of BC, but also improved the quantities and types of PFRs in BC, which promoted the production of OH. In addition, the possible mechanism for H 2 O 2 activation by PFRs in BC is that the single-electron transferring from sp2 C C, C O, pyridonic-N and pyridinic-N of PFRs in BC to H 2 O 2 , thus leading to the generation of OH. [ABSTRACT FROM AUTHOR]

Sustainable management of contaminated biomass derived from phytoremediation of metal(loid) polluted soil and water is of great importance to avoid environmental risks from secondary pollution of the contaminants. In this regard, pyrolysis technology may reduce the environmental risk of the contaminants and produce different bio-products from contaminated biomass. In this work, slow pyrolysis of Avicennia marina biomass was conducted to compare the pyrolysis properties of heavy-metal-contaminated and uncontaminated biomass and its potential to generate pyrolytic products, such as biochar, bio-oil and pyrolytic gas at a varying temperature range from 300 to 800 °C. The results indicated that the properties of biomass and derivatives were affected significantly by both pyrolysis temperature and the presence of heavy metal(loid)s. The heavy metal(loid)s in biomass contributed to higher biochar and pyrolytic gas yields at the expense of bio-oil. Increasing pyrolysis temperature induced the volatilisation of heavy metal(loid)s in biochar samples. At the same pyrolysis temperature, the contaminants significantly increased the ash content whilst decreased the fixed carbon content in biochars (p < 0.05). Furthermore, it was noticed that the quality of bio-oils was improved by the presence of metal(loid)s, as the pyrolysis of contaminated biomass produced 8–11% hydrocarbons in the bio-oil samples with less oxygenated compounds as compared to uncontaminated biomass that produced only 4–5.8% hydrocarbons in the bio-oil. Moreover, biomass abound with trace metal(loid)s produced more H 2 and CO 2 during pyrolysis compared to uncontaminated biomass. Overall, this study demonstrated that pyrolysis is an efficient way for converting heavy metal contaminated biomass obtained from phytoremediation into valuable products, contributing to the sustainability of phytoremediation. Image 1062189 • Contaminated and uncontaminated biomass and pyrolytic products were studied. • Temperature and contaminants affected biomass and pyrolysis products properties. • The biochar yield was significantly increased with presence of heavy metal(loid)s. • Heavy metal(loid)s were enriched in biochars by pyrolysis at lower temperatures. • Hydrocarbons in bio-oils increased greatly with presence of heavy metal(loid)s. [ABSTRACT FROM AUTHOR]

Persistent free radicals (PFRs) in biochar have been found to the transformation of organic contaminants in environment. However, there remains insufficient comprehension on the relationship of biochar aging with interfacial reactivity of PFRs to the degradation of phenolic compound in geochemical process. Herein, we studied both sorption and degradation of p -nitrophenol (PNP) on fresh and aged biochars via H 2 O 2 aging under anoxic condition. With increasing aging extent, the enhancive proportion of O-centered radicals was observed progressively as indicated by increased g factors. The aging of PS350 annihilated the presence of PFRs in aged biochars of low-temperature, weakening PFR intensity. But, the aging of PS650 supplied more O-centered radicals for aged biochars of high-temperature, enhancing PFR intensity. This caused the decreased degradation on 5%PS350 and 15%PS350 (37.7–79.6% decline), whereas the increased degradation on 5%PS650 and 15%PS650 (33.3–55.8% increase). At similar intensity and species of PFRs, more adsorbed amount on fresh and aged biochars produced more degradation of PNP. Nevertheless, when PFR intensity of PS650 was much lower than that of PS350, despite high sorption capacity of PS650, the degradation amount of PS350 and PS650 was comparable. The results indicated that the reactivity of C-centered radicals of PS650 was stronger than that of O-centered radicals of PS350 in anoxic system. Overall, the interfacial reactivity of biochars was simultaneously regulated by the sorption capacity of biochars and intensity and species of PFRs. This work provides a deep perspective to the impact of biochar aging on the interfacial reactivity of PRFs to phenolic compound, which will be beneficial to accurately predict the fate of organic contaminant in carbon-rich environment. [Display omitted] • Intensity and species of persistent free radical are affected by biochar aging. • An inverse degradation appears for aged biochars of low- and high-temperatures. • More sorption on fresh and aged biochars can produce more PNP degradation. • The reactivity of biochar is dependent on the intensity and species of PFRs. • The reactivity of C-centered radical is stronger than that of O-centered radical. [ABSTRACT FROM AUTHOR]

The use of biochar (BC) as a substrate and dopant in developing composite biochar-based photocatalysts (BBP) has proven to be highly promising in advancing wastewater treatment technology. This review focuses on the development of BBP using agricultural and poultry waste-derived BC to mitigate organic pollutants in water, with emphasis on the synthesis technique employed for the preparation of various BBP. Various techniques for preparing BC and BBP, along with its features and physico-chemical properties, are discussed in detail. The review then delves into the role of BC in influencing the inherent properties of the BBP, particularly in reducing band gap, acting as an electron sink or reservoir, increasing surface active regions, and improving charge separation. Furthermore, the review outlines the synergistic improvement brought about by BC in BBP, specifically in terms of the photodegradation of different classes of pollutants, i.e. pharmaceutical waste, dye from the textile industry, and phenolic compounds. Lastly, the crucial challenges associated with the practical employment of BBP in real-time applications, such as scaling up, long-term stability, and retrofitting into existing wastewater remediation technologies are elaborated. This review will provide significant insights for readers evaluating the sources of BC used as substrates and the methods employed to develop efficient BBP for the remediation of various organic pollutants. • Effective synthesis technique of photocatalyst using biochar as a substrate. • Changes in physico-chemical properties via different synthesis techniques. • Photocatalytic improvement due to the incorporation of biochar. • Effectiveness in treating different pollutants via photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar addition promoted PAHs removal during continuous anaerobic digestion (AD). • VFAs accumulation inhibited PAHs biodegradation and related genes expression. • Distribution and biodegradation mechanisms of PAHs during AD were revealed. • Biochar enhanced functional pathways of hydrolytic acidification and acetogenesis. • Direct interspecies electron transfer was key to efficient and stable methanogenesis. Alleviating acid inhibition is the most important for optimizing anaerobic digestion (AD), but the recalcitrant organic pollutants in digestates have long been ignored. In this study, we aimed to simultaneously enhance both organics bio-methanation and recalcitrant polycyclic aromatic hydrocarbons (PAHs) removal in AD system by using granule biochar and short-term ethanol stimulation. The results showed that adding biochar effectively alleviated volatile fatty acids (VFAs) accumulation and achieved 313.6 mL CH 4 /d•g COD average yield. Meanwhile, the efficiency of phenanthrene (PHE) biodegradation, as the model PAHs pollutant, was significantly promoted by 37.1%. Additionally, more and compact extracellular polymeric substances improved electron transfer and mass transfer among microbes, and higher enzymes (ATPase, NADH and α-Amylase) activities met the physiological demanding of efficient microbial metabolism in biochar-added reactor. Microbiological analysis revealed that biochar-mediated direct interspecies electron transfer (DIET) selectively enriched exoelectrogens (Bacteroides , Proteiniphilum , f_Christensenellaceae , etc.) and acetoclastic Methanosaeta , which contributed to increasing biomethane production. The promoted PAHs biodegradation was mainly dependent on the cooperation between fermenting f_Paludibacteraceae and hydrogenotrophic Methanolinea , and potentially related to biochar-mediated DIET. Metabolic analysis indicated that the metabolic pathways of acetogenesis and methanogenesis were significantly strengthened by biochar, thus alleviating acid inhibition. Also, biochar stimulated functional genes expression in PAHs anaerobic biodegradation. These findings were further verified by a series of short-term metabolism tests. [ABSTRACT FROM AUTHOR]

• Solvothermal treatment enhanced the quantity of active groups (OH, NHR and R N C O) and amorphous carbon structure. • The SRHH-180 displayed superior dye adsorption and degradation performance itself. • Up to 93% removal efficiency was reached during entirely reaction system. • Both pseudo-second-order and intraparticle diffusion models fitted well with actual adsorption process. In this study, an activated biochar derived from Spartina alterniflora (SRHH) was innovatively synthesized to efficiently remove dye contaminants from aqueous solution. A series of characterizations exhibited that solvothermal process effectively increased the mesopores and functional group structure (OH, NHR, C O, C O and R N C O) of the nanomaterial, which could also acquire amorphous carbon-doped biochar with less energy consumption. Moreover, the results showed that the as-prepared sample in a solvothermal kettle at 180 °C displayed superior dye adsorption and degradation performance, and the removal efficiency entirely could reach up to 93% within 4 h at neutral condition. The adsorption process was both consistent well with the pseudo-second-order and intraparticle diffusion models, indicating that diffusion resistance within the particle pore size and chemical action might be predominantly controlled factor. Therefore, the prepared catalyst has enormous potential in the removal of organic pollution as a low-cost and economical in-situ remediation material. [ABSTRACT FROM AUTHOR]

Groundwater serves as the primary source of drinking water for nearly half of the world's population. However, it is often contaminated with heavy metals, nitrates, fluorides, chlorides, and emerging contaminants, posing risks to human health. Treating groundwater to deliver safe drinking water is crucial, and biochar has emerged as a promising solution. While pristine biochar has proven to be an effective adsorbent in terms of performance, cost and regeneration capabilities, various studies have reported modification methods to further enhance its adsorption capacities. Although significant research has focused on efficacy of pristine and modified biochar in removing contaminants from aqueous solutions, its application for groundwater treatment remains limited. This study presents a systematic review consolidating knowledge on both pristine and modified biochar for the removal of inorganic and organic pollutants from groundwater. The review explores adsorption mechanisms, modification techniques, and the economic and environmental impacts of biochar application. It also emphasizes the need for future studies to concentrate on the interconnectivity of performance, cost, and environmental impacts of both pristine and modified biochar as well as their practical application in groundwater treatment for drinking water purposes. [Display omitted] • Role of pristine and modified biochar in groundwater pollutants adsorption reviewed. • Influential factors in the adsorption of inorganic and organic pollutants presented. • Biochar involves different mechanisms for adsorption of inorganics and organics. • Economic and environmental impacts of biochar application presented. • Improvements and research needs for the future are highlighted. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel seaweed (Capsosiphon fulvescens) biochar was prepared by single-step pyrolysis. • The intrinsic heteroatoms and trace metal enhances catalytic activity in the CFBC. • The electron transfer pathway is a more dominant reactive species in the PDS/CFBC 800. • CFBC 800 can be a promising catalyst for antibiotic degradation in an aqueous solution. • CFBC 800 is an eco-friendly catalyst for groundwater treatment. This study explores the catalytic activity of biochar materials derived from seaweed biomass (Capsosiphon fulvescens) for groundwater treatment. A facile pyrolysis process was utilized to prepare C. fulvescens biochar (CFBC X), where X represents the pyrolysis temperature. The instrumental analysis using surface characterization techniques revealed that CFBC 800 inherently contained heteroatoms (N, P) and a trace metal (Fe) in the biochar. The adsorption kinetics and isotherm experiments depicted a mixed mechanism of physical and chemical adsorption of SDZ on CFBC. Consequently, in optimal conditions with 2 mM peroxydisulfate (PDS), 200 mg L−1 CFBC 800 , and 6.1 initial solution pH, SDZ degradation (>97.2%) is achieved within 60 min. Chemical quenching tests indicate the involvement of radical (O 2 •– = 41.6%) and non-radical processes, including electron transfer (58.4%), in the PDS/CFBC 800 system. The electron spin resonance spectroscopy confirmed the formation of reactive oxygen species (ROS) in the PDS/CFBC 800 system, including radical (O 2 •–, SO 4 •–, and HO•) and non-radical (1O 2) species. Furthermore, electrochemical studies demonstrated the existence of an electron transfer pathway in the non-radical process of the PDS/CFBC 800 system. Based on chemical scavenger and ESR analyses, the PDS/CFBC 800 system exhibited both radical and non-radical mechanisms, with the electron transfer pathway being more dominant in this catalytic system. The excellent catalytic activity of the PDS/CFBC 800 system toward co-existing ions and various organic contaminant degradation is demonstrated. Moreover, the CFBC 800 -activated PDS system successfully demonstrated catalyst reusability in SDZ degradation. Thus, this study establishes CFBC 800 as an ecofriendly catalyst with remarkable catalytic activity for groundwater remediation. [ABSTRACT FROM AUTHOR]

• Key processes and governing mechanisms of Cr removal by biochars are digested. • Targeted synthesis of biochar is proposed to improve the performance of Cr removal. • Influencing factors of Cr removal are analyzed with a focus on their corresponding effect. • Applications in treating Cr-contaminated wastewater and advantages of biochar are discussed. Biochar has caught much attention owing to its excellent characteristics and prominent performance in the treatment of various contaminants. Many studies have demonstrated that biochar displays brilliant capacity for Chromium (Cr) removal and holds great promise for practical applications. There is a critical need to summarize recent developments in the preparations and applications of biochars especially engineered ones in removing Cr from water. To satisfy this need, this critical review first digests the key processes and governing mechanisms that control the removal of Cr by biochars. It then summarizes various novel preparation and modification techniques designed based on the mechanisms for maximizing biochar performance. In addition, the review also evaluates the influencing factors with a focus on their corresponding effect on Cr removal by biochar, thereby providing insights into optimal operation conditions. Most importantly, it innovatively outlines several practical applications cases of biochars in treating Cr contaminated wastewater to demonstrate their robust performs even under harsh conditions. At the end, the review outlines final conclusions and future research directions to further promote the application of biochar in the remediation of Cr in water. [ABSTRACT FROM AUTHOR]

Chromium (Cr) is one of the common environmental pollutants, which causes severe health hazards on human health and environmental security. In this study, we characterized two biochars, a raw biochar (RBC) and a Fe-modified biochar (MBC) made from poplar wood chips and determined the effect of the two biochars on remediation of hexavalent chromium (Cr(VI)) in hydroponic system by monitoring Pak choi growth. Results showed the surface area, pore number and pore volume were significantly higher in MBC than in PBC, but the pore size was larger in PBC than in MBC. When compared to the control, low concentrations of Cr(VI) (≤2 mg L−1) promoted the growth and biomass production of Pak choi by 10–78%. In contrast, the high concentrations of Cr(VI) (≥4 mg L−1) showed a significantly reduction of the growth and biomass production of Pak choi by 10–28%. Fe-modified biochar (MBC) had a more significant impact than RBC on the remediation of Cr in the Cr(VI) pollution and improved growth and biomass production of Pak choi to a greater extent. Our study indicated that MBC has a better effect on degrading Cr(VI) pollution. The findings provide scientific basis and reference for the remediation of heavy metals in aquatic ecosystems by using biochar. • Fe-modified biochar (MBC) was derived from poplar wood chips. • MBC had optimized physicochemical properties as a Cr(VI) amendment. • MBC addition is more effective in reducing Cr from Cr(VI) solution than raw biochar addition. • Physiological and biochemical activities of Pak choi were inhibited at Cr(VI) concentration (≥4 mg/L). [ABSTRACT FROM AUTHOR]

The information on the collaborative removal of nitrate and trace organic contaminants in the thin-layer capping system covered with Fe-loaded biochar (FeBC) is limited. The community changes of bacteria, archaea and fungi, and their co-occurrence patterns during the remediation processes are also unknown. In this study, the optimized biochar (BC) and FeBC were selected as the capping materials in a batch experiment for the remediation of overlying water and sediment polluted with nitrate and bisphenol A (BPA). The community structure and metabolic activities of bacteria, archaea and fungi were investigated. During the incubation (28 d), the nitrate in overlying water decreased from 29.6 to 11.0 mg L−1 in the FeBC group, 2.9 and 1.8 times higher than the removal efficiencies in Control and BC group. The nitrate in the sediment declined from 5.03 to 0.75 mg kg−1 in the FeBC group, 1.3 and 1.1 times higher than those in Control and BC group. The BPA content in the overlying water in BC group and FeBC group maintained below 0.4 mg L−1 during incubation, signally lower than in the Control group. After capping with FeBC, a series of species in bacteria, archaea and fungi could collaboratively contribute to the removal of nitrate and BPA. In the FeBC group, more metabolism pathways related to nitrogen metabolism (KO00910) and Bisphenol degradation (KO00363) were generated. The co-occurrence network analysis manifested a more intense interaction within bacteria communities than archaea and fungi. Proteobacteria, Firmicutes, Actinobacteria in bacteria, and Crenarchaeota in archaea are verified keystone species in co-occurrence network construction. The information demonstrated the improved pollutant attenuation by optimizing biochar properties, improving microbial diversity and upgrading microbial metabolic activities. Our results are of significance in providing theoretical guidance on the remediation of sediments polluted with nitrate and trace organic contaminants. [Display omitted] • Fe-loaded biochar capping is feasible for sediment nitrogen and BPA removal. • Bacteria and archaea communities play key roles in the system. • Specialized but interdependent clusters facilitated remediation process. • Remediation efficiency relates to biochar properties and interdomain interactions. [ABSTRACT FROM AUTHOR]

Quinolone antibiotics are emerging environmental contaminants, which cause serious harm to the ecological environment and human health. How to effectively remove these emerging pollutants from water remains a major challenge worldwide. In this study, a novel Fe/Ti biochar composite (Fe/Ti-MBC) was prepared by facile one-step co-pyrolysis of wood chips with hematite and titanium dioxide (TiO 2) for adsorption and photocatalytic degradation of ciprofloxacin (CIP) and norfloxacin (NOR) in water. The results showed that the degradation efficiencies of Fe/Ti-MBC to CIP and NOR were 88.4% and 88.0%, respectively. The π-π interactions and polar interactions are the main adsorption mechanisms for CIP and NOR. In the photocatalytic process, h+ and ·OH are the main active substances for the oxidative degradation of CIP and NOR. This study shows that Fe/Ti-MBC is an effective and recyclable composite, providing a novel alternative way for antibiotics degradation. [Display omitted] • Fe/Ti-MBC shows good adsorption performance for NOR and CIP. • Solution pH is an important factor affecting adsorption and photocatalysis. • The π-π and polar interactions are the main adsorption mechanisms. • ·OH and h+ are the main active species for the photocatalytic degradation of CIP and NOR. • Fe/Ti-MBC has a good adsorption and degradation effect in the actual water. [ABSTRACT FROM AUTHOR]

In order to fully exploit the potential of magnetic biochar-based persulfate (PS) systems, N was utilized to modify the magnetic biochar-based catalysts through impregnation-pyrolysis method. A typical antifungal drug, metronidazole (MNZ), is selected as the target pollutant to score the reactivity of as-synthetic nitrogen-rich magnetic biochar (NMBC) catalysts. In the modified system, 99.6% of MNZ was removed, 13.6 times of that in the unmodified system. Active radical verification experiments showed that 1O2 was the key active radical. Various characterization showed that the nitrogen-rich significantly improved the persistent free radical, defect degree, content of oxygen-containing groups, electrochemical conductivity and other catalytic activity related properties. Physicochemical characterization, Fe(II) semi-quantitative analysis and masking experiments confirmed that the doping of magnetic biochar with nitrogen increased its Fe(II) content (23.79 mg/g), approximately 2.6 times higher than that of pristine magnetic biochar. Moreover, N induces strong electron accretion of Fe atom through coordination bond, which leads to the increase of electron density on the Fe atom, which increases the content of Fe (II) in the material, thus improving the ability of the material to activate PS to generate 1O 2 , and promoting the degradation reaction of MNZ. This paper provides a method to improve the activation performance of magnetic biochar. [Display omitted] • Urea was used to improve the activation performance of magnetic biochar. • Nitrogen-rich magnetic biochar has high degradation activity of metronidazole. • The mechanism of activation of PS by nitrogen-rich magnetic biochar had been proposed. [ABSTRACT FROM AUTHOR]

Biochar (BC) is attracting increasing concerns on the scavenging of toxic contaminants from water because of its low-cost and environmental-friendly properties, however, the adsorption performance of pristine BC for common organic contaminants. Consequently, adopting available modification methods to strengthen the uptake performance of BC is necessary, unfortunately, there are few summaries on various functionalization techniques of BC with corresponding mechanisms on removing organic contaminants. Herein, this review aims to describe (i) the preparation methods of pristine BC and the influence of different pyrolysis parameters; (ii) various modification techniques for BC including liquid modification, gas modification, ball milling modification, metal nanoparticles loading, and near-nature BC-based immobilized materials; (iii) the applications of functionalized BC on organic pollutants removal with related adsorption mechanisms (iv) crucial factors (e.g. solution pH, contact time, and co-existing ions); influencing the removal process of functionalized BC on organic contaminants with application potential of modified BC as an adsorbent in environmental fields; (v) some useful and constructive proposals to improve the practical application of functionalized BC in future research. This review advanced the comprehensive understanding of application of functionalized BC as effective adsorbent with low-cost and high-performance properties for the remediation of contaminated water. [Display omitted] • Synthesis methods and removal performance of BC for organic pollutants are presented. • Advancements in the functionalization of BC for enhanced adsorption are summarized. • Adsorptive mechanisms of functionalized BC for organic pollutants are discussed. • Critical factors affecting adsorption performance of functionalized BC are analyzed. • Constructive suggestions for further applications of functionalized BC are proposed. [ABSTRACT FROM AUTHOR]

The general environmental quality has a direct impact on how well life is supported on earth. There are fewer and fewer water sources available, and those that are available are contaminated with many pollutants. Pollution of biological and chemical systems can result from heavy metal and dye poisoning of water resources. Agricultural waste benefits from a variety of sources, cheap cost, and renewable energy. When these wastes are converted into useful applications, such as environmental adsorbents for eliminating pollutants, biochar (BC), composts, and natural fertilizers, rather than burning them in open fields, which results in various environmental problems like air pollution and soil erosion, they may represent a treasure. The transformation of waste into useful compounds is one of the most significant scientific topics. This critical study evaluates current advancements in the utilization of (nano)materials obtained from agricultural waste for environmental decontamination and pollutant monitoring or removal. Along with highlighting the most promising research areas, this section discusses the major challenges to the removal of organic dyes, toxic ions, and other contaminants using diverse methods including adsorption, reduction, and ion exchange using cost-effective materials generated from agricultural wastes. Advanced (nano)materials synthesized using agricultural wastes for the reduction/degradation of environmental pollutants, are highlighted. [Display omitted] • Application of agricultural wastes in the synthesis of (nano)materials. • Application of agricultural waste-derived nanomaterials in water treatment. • Catalytic reduction of dyes, nitroarenes, and removal of heavy metal, are presented. • Future challenges for the preparation of these nanomaterials are discussed. [ABSTRACT FROM AUTHOR]