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Per- and polyfluoroalkyl substances (PFAS) present significant environmental and health hazards due to their inherent persistence, ubiquitous presence in the environment, and propensity for bioaccumulation. Consequently, the development of efficacious remediation strategies for soil and water contaminated with PFAS is imperative. Biochar, with its unique properties, has emerged as a cost-effective adsorbent for PFAS. Despite this, a comprehensive review of the factors influencing PFAS adsorption and immobilization by biochar is lacking. This narrative review examines recent findings indicating that the application of biochar can effectively immobilize PFAS, thereby mitigating their environmental transport and subsequent ecological impact. In addition, this paper reviewed the sorption mechanisms of biochar and the factors affecting its sorption efficiency. The high effectiveness of biochars in PFAS remediation has been attributed to their high porosity in the right pore size range (>1.5 nm) that can accommodate the relatively large PFAS molecules (>1.02-2.20 nm), leading to physical entrapment. Effective sorption requires attraction or bonding to the biochar framework. Binding is stronger for long-chain PFAS than for short-chain PFAS, as attractive forces between long hydrophobic CF 2 -tails more easily overcome the repulsion of the often-anionic head groups by net negatively charged biochars. This review summarizes case studies and field applications highlighting the effectiveness of biochar across various matrices, showcasing its strong binding with PFAS. We suggest that research should focus on improving the adsorption performance of biochar for short-chain PFAS compounds. Establishing the significance of biochar surface electrical charge in the adsorption process of PFAS is necessary, as well as quantifying the respective contributions of electrostatic forces and hydrophobic van der Waals forces to the adsorption of both short- and long-chain PFAS. There is an urgent need for validation of the effectiveness of the biochar effect in actual environmental conditions through prolonged outdoor testing., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose, financial or otherwise., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The increasing presence of oxytetracycline (OTC) in agricultural soils has raised global environmental concerns. We investigated the environmental behavior and fate of OTC in two types of tropical agricultural soils, focusing on the impact of dissolved organic matter (DOM) from biogas slurry. Techniques such as three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM), Fourier Transform Infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and Ultraviolet-visible spectrophotometer (UV-vis) were used to explore the adsorption mechanisms. Our findings revealed that biogas slurry-derived DOM decreased the OTC adsorption on soils and extended the time to reach adsorption equilibrium. Specifically, the equilibrium adsorption of OTC by the two soils decreased by 19.41 and 15.32 %, respectively. These adsorption processes were effectively modelled by Elovich, intraparticle diffusion, linear, and Freundlich thermodynamic models. Thermodynamic parameters suggested that OTC adsorption onto soils was spontaneous and endothermic, with competitive interactions between biogas slurry-derived DOM and OTC molecules intensifying at higher DOM concentrations. The adsorption mechanisms were governed by both physical and chemical processes. Furthermore, the presence of Ca 2+ and Na + ions significantly inhibited OTC adsorption. These insights advanced our understanding of the fate and risk of OTC in soil environments influenced by DOM, contributing to more informed agricultural and environmental management practices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Simultaneous removal of toxic elements and pharmaceutical compounds at environmentally relevant concentrations in aqueous solution is challenging. Modification of biochar using environmental materials has attracted significant attention in wastewater treatment, while pristine biochar has several limitations in the simultaneous removal of Lead (Pb 2+ ), Copper (Cu 2+ ), and metoprolol. We investigated the efficacy of biochar composites using waste cabbage leaves-derived biochar with kaolinite, and anthocyanin for simultaneous removal of Pb 2+ , Cu 2+ , and metoprolol from water. Using ball milling, the surface area and functional groups of adsorbents were improved via breaking the biochar grains into ultrafine particles. Ball-milled biochar derived from waste cabbage leaves significantly increased Pb 2+ , Cu 2+ , and metoprolol adsorption by 105, 71, and 213%, respectively. Results of Brunauer Emmett Teller surface area, Fourier transform infrared and X-ray photoelectron spectroscopies showed that surface area of non-milled biochar improved nearly ten-fold following ball-milling, while several oxygen containing acidic functional groups also increased. The adsorbents resulted in high removal efficiency for Pb 2+ (162.9 mg/g) and Cu 2+ (48.5 mg/g) in ball milled-kaolinite composite biochar (BMKB) and 76.3 mg/g (metoprolol), respectively in ball milled-anthocyanin composite biochar (BMAB). The simultaneous sorption of Pb 2+ , Cu 2+ , and metoprolol in an aqueous solution to BMAB and BMKB, showed that the adsorption capacity followed the order of Pb 2+ >Cu 2+  > metoprolol in both types of ball-milled biochars. BMKB achieved a high adsorption capacity for Pb 2+ and Cu 2+ (59 mg/g and 50 mg/g), respectively, while BMAB exhibited an adsorption capacity 22.3 mg/g for metoprolol. It was postulated that sorption of Pb 2+ , Cu 2+ and metoprolol involved multiple adsorption mechanisms namely surface complexation, π-π interaction, H-bond, pore filling, and ion bridging. The findings of this study revealed that ball milling is a potential technology in producing a highlyefficient adsorbent to remediate multi-contaminants in aqueous solution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Globally, COVID-19 has not only caused tremendous negative health, social and economic impacts, but it has also led to environmental issues such as a massive increase in biomedical waste. The biomedical waste (BMW) was generated from centralized (hospitals, clinics, and research facilities) and extended (quarantine camps, COVID-19 test camps, and quarantined homes) healthcare facilities. Many effects, such as the possibility of infection spread, unlawful dumping/disposal, and an increase in toxic emissions by common BMW treatment facilities, are conjectured because of the rise in waste generation. However, it is also an opportunity to critically analyze the current BMW treatment scenario and implement changes to make the system more economical and environmentally sustainable. In this review, the waste disposal guidelines of the BMW management infrastructure are critically analyzed for many functional parameters to bring out possible applications and limitations of individual interventions. In addition, an investigation was made to select appropriate technology based on the environmental setting., Competing Interests: Declaration of competing interest All authors agree to their participation in this manuscript preparation and all authors also disclose that there are no financial and personal relationships with other people or organizations and no conflict of interest among the authors or organizations involved in this manuscript., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The emerging toxicants, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q), resulting from environmental exposure to N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), have gained considerable attention owing to their ubiquitous occurrence and high toxicity. We performed a scientometric analysis on this topical area of research over the past two decades, spanning from 2004 to April 2024. The overarching aim was to reveal potential future directions in this research area, exploring several key aspects. These included publication and citation growth trends, relevant subject fields, distribution of contribution by country, influential journals in the field, keyword co-occurrence network and cluster analysis, and identification of top authors. The information was collected from the Scopus database and processed using the VOS viewer software. We observed a notable increase in the number of publications over the past four years. With a share of 46.2% of publications, "Environmental Sciences" dominated as the primary scientific category. Among all journals, "Science of the Total Environment" was the most prolific, publishing 33 documents, accounting for 15.6% of the total records. China, representing 76 publications (36%), followed by the United States, with 40 (18.9%), stood out as the leading countries. The occurrence of keywords such as "Pollution exposure", "Mass spectrometry", and "toxicity" highlighted the importance of assessing the toxicological properties, analytical methods, and environmental implications of these emerging contaminants to mitigate their adverse effects and protect environmental and human health. Cai, Zongwei from Hong Kong Baptist University was highly productive in this field, publishing 11 papers. Based on the bibliometric analysis presented, it seems that the future direction of research on 6PPD and 6PPD-Q will shift towards strategies focused on their removal and treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The effects of adding green-synthesized magnetic iron-containing nanoparticles (GSMFe) onto biochar in aqueous solution for the adsorptive removal of hexavalent chromium [Cr(VI)] were investigated in this study. Nanocomposites, denoted as green synthesis magnetic biochar (GSMB), were created using a green synthesis technique with white tea residue to introduce GSMFe into biochar. Six adsorbents, varying in GSMFe content, were tested for their effectiveness in eliminating Cr(VI), a globally significant hazardous heavy metal. The results demonstrated that incorporating GSMFe into biochar led to significant improvements in adsorption capacity and saturation magnetization. With an increasing amount of GSMFe, the maximum adsorption capacity increased from 2.47 mg/g (EWTWB) to 9.11 mg/g (GSMB4). The highest saturation magnetization was achieved at 13.4 Am 2 /kg at GSMB4. Similarly, surface areas rose up to 72.9 m 2 /g at GSMB3 but declined thereafter due to GSMFe aggregation and pore blockage. Sorption behavior for Cr(VI) was assessed using five isotherm models, with the Redlich-Peterson model showing the best fit. The analysis of approximate site energy distribution (SED) indicates that the incorporation of GSMFe enhances the frequency of the entire range of sorption energy sites, while the biochar matrix contributes to a slight increase in medium sorption energy sites within the GSMFe. Among the GSMBs, the difference were more pronounced at low-energy sites than at high-energy sites. At higher energy sites (27,500-40,000 J/mol), sorption site frequencies remained similar, regardless of GSMFe content and associated physicochemical properties. For sorption energy site values exceeding 17,500 J/mol (Cr(VI) concentration below 50 mg/L), GSMB2 is regarded as a more practical choice due to its relatively large area under the frequency distribution curve and commendable cost-effectiveness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Indonesia plans to mitigate the environmental emissions, particularly the carbon emissions, from the transport by replacing conventional buses with battery electric buses (BEBs). However, there are limited studies on the potential environmental benefits of BEBs and mostly focused on carbon emissions. In this study, the environmental impacts of adopting BEBs in Jakarta's public transportation system were examined using Life Cycle Assessment (LCA) to better understand its potential environmental impacts. Using LCA, the environmental impacts of BEBs were also compared with conventional buses across their life cycles, which included raw materials extraction until the end of life stages. The results showed diesel buses have generally lower environmental impacts than BEBs due to the high share of fossil fuels in the electricity generation in Indonesia. Scenario analysis showed that extending the life cycle, using different battery disposal methods, and using battery reuse could lead to higher environmental benefits in using BEBs. Among the scenarios considered in the study, prolonging the lifespan of the bus to 32 years, using electricity mix with a higher share of renewable energy and reusing the lithium-ion batteries, BEBs would have lesser environmental impact per kilometre. In particular, the particulate matter formation (PM 2.5 ) dropped 21 %, while the overall life cycle of BEB using the highest renewable scenario showed an average of 25 % improvement compared to the baseline scenario regarding environmental impact., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Febelyn Reguyal reports financial support was provided by Ministry of Business Innovation and Employment. Moses Gregory Ginting reports financial support was provided by Ministry of Finance of Republic of Indonesia. Maria Valentina Cecilia reports financial support was provided by Ministry of Finance of Republic of Indonesia., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

New Zealand's goal to be carbon neutral by 2050 has led to the development of strategic policies and schemes to encourage the use of electric vehicles (EVs). However, most studies are focused on the greenhouse gas emissions of EVs while limited studies are available on their other potential environmental impacts. Using life cycle assessment (LCA), the environmental impacts of EV adoption, specifically the battery electric vehicle (BEV), were assessed to determine the future environmental challenges for New Zealand. Due to 87.1 % share of renewable sources of electricity generation in New Zealand in 2022, EV adoption has demonstrated its strong potential to reduce the CO 2 emission of the transport sector. Results showed that lithium-ion battery (LIB), including production and disposal, is the major contributor to the environmental impacts of BEV adoption. The direct environmental impacts of BEV in New Zealand range from 0.34 % to 42.5 % across its life cycle. The results are sensitive to the assumptions of the driving range and number of LIB replacements where they could increase up to 34.5 % per km and up to 48.9 % per replacement of LIB on environmental impacts, respectively. Scenario analysis also showed that when the renewable energy share in electricity production is increased to 100 %, the environmental impacts of the BEV life cycle could be reduced by up to 14.5 % while it could decrease by up to 69.6 % in New Zealand. Additionally, reusing the spent LIB for other purposes would have the least environmental impacts on disposal among the options considered in the study. Therefore, New Zealand would benefit the most from BEV adoption by generating 100 % electricity from renewable sources, and developing policies and schemes to repurpose LIB at its end of life., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Febelyn Reguyal reports financial support was provided by NZ Ministry of Business, Innovation and Employment., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Green synthesized magnetic nanoparticles were impregnated into biochar matrix (EWTWB) to produce biochar-supported magnetic nanocomposite (GSMB). Instead of chemicals, organic matters in white tea waste extract were used as reductant, surfactant and functional capping materials. Magnetic biochar produced from traditional methods of pyrolysis (PMB) and co-precipitation (Co-PreMB) were prepared to compare their properties with GSMB. Xray Diffraction confirmed the main component of green synthesized particles is Fe 3 O 4 . When compared with PMB and Co-PreMB, the Fe 3 O 4 produced by co-precipitation method has higher purity while the products from green synthesis method are complex and contain a small portion of other iron-containing compounds. As a consequence, Co-PreMB has higher saturation magnetisation value than GSMB, which are 31.3 and 11.5 Am 2 /kg, respectively. GSMB was also found to be less stable in acidic conditions (pH ≤ 4) than Co-PreMB. However, the SEM results exhibited that spherical magnetic nanoparticles (20-50 nm) were successfully formed and distributed on the surface of biochar via green synthesis method while serious aggregation occurred on the surface of Co-PreMB. According to the result of BET, the surface area of GSMB increased dramatically from 0.2 m 2 /g to 59.7 m 2 /g. Fourier Transform Infrared spectroscopy and Xray photoelectron spectroscopy results showed the presence of rich oxygen-containing functional groups on the GSMB, The high surface area coupled with rich functional groups on the GSMB made the whole synthesis process an environmentally friendly and greener, to prepare magnetic biochar for application in wastewater treatment., Competing Interests: Declaration of competing interest All authors agree to their participation in this manuscript preparation and All authors also disclose that there is no financial and personal relationships with other people or organizations and no conflict of interest amongst the authors or organisations involved in this manuscript., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

A novel biochar-based magnetic nanocomposite (GSMB) was prepared from white tea waste via green synthesis method. The sorption properties and regeneration of GSMB were studied using Pb(II) and Cd(II) to better understand its ability in heavy metal recovery. The adsorption kinetics data were modelled using pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models, while Pb(II) and Cd(II) isotherms were modelled with Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models. Results showed that Pb(II) adsorption was well described by pseudo-second order while the Elovich model best described the Cd(II) adsorption trend, indicating the sorption of Pb(II) and Cd(II) onto GSMB were dominated by chemisoprtion rather than physisorption. Langmuir model gave the best fit to Pb(II) sorption, and the Cd(II) adsorption was well described by Temkin model. The maximum adsorption capacity of Pb(II) and Cd(II) onto GSMB were 81.6 mg/g and 38.6 mg/g, respectively. Scanning electron microscope coupled with energy dispersive x-ray, X-ray diffraction and Fourier transform infrared spectroscopy analyses revealed that iron oxides played a key role during adsorption process and the adsorption mechanisms include surface electrostatic attraction and surface complexation for both metals. Among the five regenerating agents studied, 0.1 M EDTA-2Na was favoured for the desorption of Pb(II) onto GMSB. The findings from the regeneration studies revealed ∼54% of Pb(II) adsorption capacity remained after three sorption-desorption cycles implying the adsorbent could potentially be further reused., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Empty fruit bunch oil palm (EFBOP) is one of the byproducts after oil palm fruitlet is removed in oil palm processing and is considered as waste. In this study, EFBOP was converted to biochar (BC-EFBOP) at 350-700 °C, with an overarching aim of determining the feasibility of adsorptive removal of manganese (a second dominant element in acid mine drainage) from water. Results showed that with increasing temperature, the BC-EFBOP yield decreased from 44.34% to 26.74%, along with the H/C (0.89%-0.29%) and O/C ratios (0.38%-0.23%), and the carbon content increased (62.7%-73.93%). As evidenced by Fourier Transform InfraRed spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS), abundant oxygen-containing surface functional groups such as hydroxyl (-OH), carboxyl (-COOH), and ether (C-O-C) were retained, and aromatic CC groups were largely generated in the biochar. Pyrolysed biochar at 350 °C (BC350), with the least surface area (0.5 m 2  g -1 ), exhibited the highest Mn 2+ adsorption capacity (8.2 mg g -1 ), whereas for BC700, with the largest surface area (2.19 m 2  g -1 ), had the lowest capacity for Mn 2+ (1.2 mg g -1 ). Regardless of the temperature, solution pH of 5 was found to be optimal for Mn 2+ removal from water. The Langmuir isotherm model best described the equilibrium adsorption data with a maximum adsorption capacity of 1.2-8.2 mg g -1 for initial concentrations of 5-250 mg L -1 , whereas the adsorption kinetics followed the pseudo-second-order model. There was nearly four-fold increase in Mn 2+ ions removal with increased biochar dosage (0.05-0.5 g), at initial Mn 2+ concentration of 100 mg L -1 . The study showed that a low-cost, environmentally friendly BC-EFBOP with optimal surface chemistry could potentially remediate Mn 2+ ions from aqueous media. However, a proper cost-benefit and techno-economic analysis is needed prior to potential pilot scale studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Understanding the occurrence and fate of antibiotics from different categories is vital to predict their environmental exposure and risks. This study presents the spatiotemporal occurrence of 45 multi-class antibiotics and their associations with suspended particulate matter (SPM) in Xiaoqing River (XRB) and Yellow River (YRB) via 10-month monitoring in East China. Thirty-five and 31 antibiotics were detected in XRB and YRB, respectively. Among them, fluoroquinolones (FQs) had the highest total mean concentration (up to 24.8 μg/L in XRB and 15.4 μg/L in YRB), followed by sulfonamides (SAs) (14.0 μg/L and 15.4 μg/L) and macrolides (MLs) (1.1 μg/L and 1.6 μg/L). Significant spatial-temporal variations were found in both rivers where higher concentrations of antibiotics were observed in urban and densely populated areas during winter and spring. Hydrological factors such as river flow and water volume, instream attenuation and antibiotic usage may cause the observed variabilities in the seasonal patterns of antibiotic pollution. Using linear regression analysis, for the first time, this study confirmed that the total concentrations of MLs (p < 0.05), FQs (p < 0.001) and SAs (p < 0.001) were strongly correlated with the turbidity/total suspended solids in the studied rivers (except MLs in YRB). It is thus suggested that partitioning processes onto SPM might affect the distribution of detected antibiotics in rivers, which are largely dependent on SPM composition and characteristics. The risk quotient (RQ) determined for up to 87 % of individual compound was below 0.1 in both rivers; however, the high joint toxicity reflected by the mixed RQs of detected antibiotics may rise risk alarm for aquatic species. Further aspects regarding active mechanisms of SPM-antibiotic interactions and ecological risks of coexistence of multiple antibiotics need to be investigated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Emerging organic contaminants (EOCs) have been widely studied in landfill leachates but not in the surrounding environment of landfills. In this study, two sampling campaigns were conducted to determine 45 EOCs in landfill leachates and environmental samples near a landfill in East China. Our study focused on the seasonal occurrence and spatial distribution of the target EOCs, as well as their ecological risks. The results showed 13 out of 45 EOCs were detectable and achieved individual concentrations that ranged from 2.0 to 5080 ng/L in the landfill leachates. Most of the detected EOCs exhibited higher concentrations in the leachates collected in summer than in winter. Effective removal of the EOCs by a two-stage disc tube reverse osmosis (DTRO) system led to a significant reduction in their concentration levels (< LOQ ~ 49 ng/L) in treated leachates. Eight EOCs (< LOQ ~ 62.7 ng/L) were detected in the groundwater adjacent to the landfill and had a similar composition pattern to raw leachates. The contamination levels of the target EOCs in groundwater decreased with the distance of sampling sites from the landfill. In soil samples, the occurrence of target EOCs was not consistent with raw or treated landfill leachates. Spatially, no apparent difference in the EOC concentrations was observed in the soil nearby the landfill. Crop plants sorbed the EOCs contained in soil (< LOQ ~ 30.4 ng/L), but they were not able to bioconcentrate the contaminants in either roots or edible parts. Risk assessment suggested that the individual EOC likely posed medium to high risks to aquatic organisms in groundwater while negligible impacts to human health through consumption of vegetables. To the best of our knowledge, this is the first report on the contribution of landfill leachates to EOC contamination in both aquatic and soil environments in East China. Our findings emphasized the importance of investigating EOCs in landfill leachates and accumulative environmental risks of EOCs in the neighboring environment of landfills in China.

We demonstrate a challenge-based innovation of End of Life Tyres (ELTs) pyrolysis for magnetic pyrochar production and synthesis with evidence of its use as low cost, novel adsorbent for pharmaceuticals removal from aqueous solutions. Magnetic tyre pyrochar (MTC) derived from ELTs at Technology Readiness Level 3-7 (TRL3-7), was tested for the removal of ciprofloxacin (CIP), propranolol (PRO) and clomipramine (CLO), from water, at varied pH and ionic strengths. The morphological and chemical properties of the adsorbents were assessed using Brunauer Emmett Teller (BET) surface area, Vibrating Sample Magnetometer (VSM), Fourier Transform Infrared (FTIR), Scanning Electron Microscope coupled with Energy Dispersive X-ray (SEM-EDS), elemental analysis and zeta potential measurements. MTC showed excellent adsorption efficiency of 85%, 90% and 92% for CIP, PRO and CLO respectively, higher than that of the non-magnetic tyre pyrochar (TC), due to the larger surface area, and porosity and lower polarity. Adsorption of the compounds onto MTC was highly pH dependent, and favourable at low ionic strength. The experimental data were well described by pseudo-second order kinetic and Freundlich isotherm models. Based on FTIR and zeta potential analysis, the interaction mechanisms were explained by cation-π, π-π EDA, cation exchange, electrostatic repulsion and hydrophobic effect. In the context of the circular economy, this ELTs based low cost magnetic adsorbent (estimated at $299/t) can be potentially used at full-scale industrial wastewater treatment for elimination of drugs from aqueous solutions, offering sustainable environmental remediation., Competing Interests: Declaration of competing interest All authors disclose that there is no financial and personal relationships with other people or organizations and no conflict of interest among the authors or organizations involved in this manuscript., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Recent studies have shown the widespread occurrence of pharmaceuticals in the aquatic environment leading to increasing global concern on their potential adverse effects in the environment and public health. In this study, we evaluated the use of magnetic biochar derived from pine sawdust, one of New Zealand's major wood wastes, to remove an emerging contaminant, sulfamethoxazole (SMX), at different pH, ionic strength, natural organic matter (NOM) and a competing compound, 17α-ethinylestradiol (EE2). In single-solute system, the sorption of SMX onto magnetic biochar was found to be highly pH-dependent and slightly increased with increase in ionic strength. However, the effects of pH, ionic strength and NOM were relatively insignificant compared to the sorption inhibition caused by EE2 in binary-solute system. Both SMX and EE2 sorption onto the highly carbonised biochar in magnetic biochar were postulated to be due to the π-π electron donor acceptor and hydrophobic interaction. EE2 is more hydrophobic than SMX. Hence, strong competition between these compounds was identified where EE2 markedly inhibited the sorption of SMX onto magnetic biochar in all artificial environmental conditions studied., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Magnetisation of carbonaceous adsorbents using iron oxides has been found to be one of the potential solutions for easy recovery of adsorbent after use. We evaluated the effects of Fe 3 O 4 nanoparticle addition on the physico-chemical properties of biochar and its sorption properties. Five adsorbents with varying amount of Fe 3 O 4 per mass of adsorbent (0%, 25%, 50%, 75% and 100%) were used to adsorb sulfamethoxazole (SMX), an emerging micropollutant. Five isotherm models were used to evaluate the sorption behaviour of SMX onto the adsorbents where Redlich-Peterson model was found to best describe the data. Based on this model, the approximate site energy distribution for each adsorbent was determined. Surface area and sorption capacity had strong negative linear relationship with the amount of Fe 3 O 4 per mass of adsorbent while the pore volume and saturation magnetisation of the adsorbent increased with increasing percentage of Fe 3 O 4 . The results of the approximate site energy distribution analysis showed that the addition of Fe 3 O 4 on biochar reduced the area under the frequency distribution curve of sorption site energies leading to the lowering of the sorption sites available for SMX. This could be attributed to the blockage of the hydrophobic surface of biochar reducing the hydrophobic interaction between SMX and biochar., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Magnetisation of carbonaceous adsorbent using iron oxide (Fe x O y ) has potential to decrease the recovery cost of spent adsorbent because it could be separated magnetically. However, formation of various phases of Fe x O y and iron hydroxide (Fe x (OH) y ) during synthesis particularly the non-magnetic phases are difficult to control and could significantly reduce the magnetic saturation of the adsorbent. Hence, formation of the most magnetic Fe x O y , Fe 3 O 4, on biochar via oxidative hydrolysis of FeCl 2 under alkaline media was performed to synthesise magnetic adsorbent using pine sawdust biochar (magnetic pine sawdust biochar: MPSB). The Fe 3 O 4 nanoparticles on the surface of biochar contributed to high saturation magnetisation of MPSB, 47.8Am 2 /kg, enabling it to be separated from aqueous solution using a magnet. MPSB were examined physically and chemically using various techniques. Sorbent-stability, parametric, kinetics, isotherm, thermodynamic and sorbent-regeneration studies were performed to comprehend the potential of MPSB as adsorbent to remove an emerging contaminant, sulfamethoxazole (SMX) from aqueous solution. Results showed that MPSB was stable within solution pH 4-9. Adsorption of SMX onto MPSB was favourable at low pH, fast and best described by Redlich-Peterson model. Adsorption was exothermic with physisorption possibly due to hydrophobic interaction and spent adsorbent could be regenerated by organic solvents., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this study, an ultrasonic irradiation technique was utilized to mitigate the fouling of polyethersulfone (PES) and polyvinylidene fluoride (PVDF) membranes. The use of ultrasound at 20 kHz was applied to a dead-end microfiltration cell in order to mitigate fouling caused by the presence of colloidal bentonite particles. The effect of ultrasonic power and pulse duration on the permeate flux recovery was examined. Measurements indicate that an increase in ultrasonic power and longer pulse duration results to a higher permeate flux recovery. In order to reduce power consumption, a low to high power shift (LHPS) and pulsation method, were investigated. Methods of cleaning such as ultrasonic irradiation, ultrasonic cleaning with forward flushing and ultrasonic cleaning with backwashing were utilized and their cleaning efficiencies were examined. The cleaning performance was assessed using the clean water flux method and scanning electron microscope analysis of the cleaned membranes. Results showed that LHPS and pulsation method both improve the permeate flux recovery but were not able to attain the 93.97 and 74.88% flux recovery for PES and PVDF that was achieved by constant-15 W ultrasonic cleaning. In addition, forward flushing and backwashing may enhance the performance of ultrasonic cleaning at 9 W but could become disadvantageous at 15 W.