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[Display omitted] • BC/FBC made from agricultural waste were pre-deposited in GDM systems. • BC pre-deposition improved biofouling layer heterogeneity thus higher stable flux. • Presence of biochar significantly enhanced microbial activity and pollutant removal. • The presence of Fe in FBC inhibits microbial activity of the biofouling layer. The relatively unstable dissolved organic removal efficiency and low water flux during long-term filtration of gravity-driven membrane (GDM) are major barriers to its widespread application in decentralized water treatment. In this study, the role of pre-deposited biochar (BC) and iron-modified biochar (FBC) layers in GDM for treating surface water were firstly investigated, aiming to explore the feasibility of cost-effective agricultural waste as pre-deposition materials. Compared to the relatively low removal efficiency of GDM control group (DOC 18.1 %, UV 254 10.6 %), both BC pre-deposited GDM (BC-GDM: DOC 36.0 %, UV 254 39.9 %) and FBC pre-deposited GDM (FBC-GDM: DOC 31.9 %, UV 254 32.4 %) show considerably enhanced removal efficacy. Also, pre-deposited BC/FBC layers accelerated the start-up process for NH 4 +-N removal. The enhancement of functional bacteria such as Proteobacteria and Nitrospirota was accountable for pollutant removal efficacy. Regarding the flux stabilization, compared to the GDM control system, the final stable flux of BC-GDM increased by 3.61 % while FBC-GDM decreased by 9.55 %. The presence of BC layer increased the bacterial activity, porosity of the formed biofouling layer, thus favored the flux enhancement, resulting in a lower water production cost. Conversely, the presence of Fe in FBC may inhibit the microbial activity and diminish its pore structure, leading to reduced flux transport. Our study suggests simple pre-deposition of BC shows positive effect on ultra-low pressure GDM filtration, highlighting the potential application of low-cost agriculture waste in decentralized drinking water treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sulfite is rapidly activated due to the efficient synergy of ultrasound and Fe0. • Ultrasound reinforces the reaction through homogeneous-heterogeneous process. • SO 4 •− and •OH are the main reactive species in the ultrasound/Fe0/sulfite system. • •H plays an important role in the conversion of reactive species. • Ultrasound/Fe0/sulfite system has great resistance to interference. A novel advanced oxidation process combining low-frequency ultrasound (US) with zero-valent iron (Fe0) and sulfite (S(IV)) has been systematically developed. The combination showed significant synergy and considerable selectivity in the degradation of 2,4,6-tribromophenol (TBP). An 89.6 % removal of TBP was achieved within 30 min using a S(IV) concentration of 0.5 mmol/L and a Fe0 dosage of 0.05 g/L at pH 7.0, accompanied by ultrasonication at 40 kHz in the US/Fe0/S(IV) system. Mechanistic studies have indicated that SO 4 •− and •OH are the main reactive species in the system, and that •H plays an important role in the conversion of reactive species. The S(IV) activation mode by Fe0 has been found to be divided into homogeneous activation and heterogeneous activation during US. Moreover, US can improve the reactions by promoting mass transfer in the aqueous phase and between the solid and liquid. In the US/Fe0/S(IV) system, TBP degradation is promoted by increases in either US power, Fe0 dosage, or temperature. Too low or too high S(IV) concentration, pH, or dissolved oxygen can have an adverse effect on the reaction. Cations have little influence on the system, except for Cu2+, while anions inhibit the degradation of TBP, except for SO 4 2−. The presence of humic substances (humic acid and fulvic acid) significantly inhibits TBP degradation. Overall, this work provides a new technique for water treatment with high efficiency and application potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • Separation mechanisms including adsorption via COF-based membranes are investigated. • The latest synthesis methods and application of COF-based membranes are highlighted. • Pioneering perspectives about existing challenges of COF-based membranes are proposed. • Theoretical guidance for designing high-performance COF-based membranes is presented. With the accelerating steps of urbanization, the freshwater scarcity has been emerging as a serious threat to sustainable economic and social development. Under this circumstance, increasing attention is shifting to alternative water sources, such as wastewater and seawater, to harvest the embedded freshwater for supplement. Membrane technology has been predominately applied in this scenario due to its huge advantages in separation efficiency and economic investment. However, the application, especially with polyamide (PA) composite membranes, is significantly limited by the unsatisfied water flux when reclaiming high-quality freshwater. Recently, covalent organic framework (COF)-based membranes with pure COF or COF-incorporated PA as the selective layer exhibited great promise in alleviating this current dilemma benefiting from its tunable aperture, regular channels and desirable hydrophilicity. Unfortunately, relative research works were mainly focusing on the structure–function relationship between COF and the resultant membrane. In the meantime, the accompanied reviews were derived mainly from summarizing membrane preparation processes and practical applications while paid insufficient attention in the separation mechanisms of the COF-based membranes, which are highly desired for directionally optimizing membrane performance from the theoretical perspective. Herein, the mechanisms involved in water purification through COF-based membranes are systematically investigated, especially in a novel view of adsorption. In addition, the up-to-date synthesis strategies of high-performance COF-based membranes are highlighted. Besides, the latest advances in structure-performance relationship of emerging COF-based membranes for wastewater purification and saltwater desalination are also described in this paper. This review aims to provide theoretical guidance and potential methods for design and preparation of next-generation COF-based membranes with higher-performance for high-quality recovery of freshwater. [ABSTRACT FROM AUTHOR]

[Display omitted] • ATL degradation was retarded with the increase in wavelengths and solution pH. • IBF and BZF were used to jointly detect the steady-state concentrations of ClO and Cl 2 −. • O 3 was the major contributor to ATL degradation in the pH range of 7.0–9.0. • The increase of pH decreased the contributions of OH and RCS, but enhanced the contribution of O 3. • Increase in pH and wavelength decreased the concentrations of DBPs. Ultraviolet A light-emitting diode (UVA-LED)-activated chlorine effectively degraded micropollutants at different irradiation wavelengths. Quenching experiments indicated that OH, reactive chlorine species (RCS), and O 3 were the main reactive species for degradation of atenolol (ATL). Bezafibrate and ibuprofen, were used for the first time to jointly quantify the concentrations of Cl 2 − and ClO. Notably, O 3 contributed most to the degradation of ATL (38.9%), following by OH (30.2%) and RCS (27.6%) at pH 7.0 by the UVA-LED/chlorine at 385 nm. ATL degradation increased with the decrease of wavelengths, due to the higher quantum yields of chlorine. The k obs of ATL was positively correlated to the quantum yield of chlorine at the UVA wavelength band. Higher light intensity could enhance the photolysis of chlorine, leading to enhanced ATL degradation. The protonated chlorine is more conducive to the degradation of ATL. Specifically, the contributions of OH, O 3 , and RCS to ATL degradation changed from 40.9%, 6.53%, and 41.0% at pH 4.0 to 11.6%, 59.9%, and 26.6% at pH 9.0, respectively. Cl− had no significant influence on ATL degradation, mainly due to the synergistic effect of different reactive species. HCO 3 − and HA inhibited ATL degradation owing to the quenching effect for reactive species and/or UV filtering effect. The primary transformation pathway of ATL included hydroxylation, chlorination, and bond-cleavage pathways based on the structures of the eight identified transformation products. Seven chlorinated disinfection by-products decreased as wavelengths and pH increased. The above results show that UVA-LED/chlorine might be an efficient process for water treatment. [ABSTRACT FROM AUTHOR]

Outbreaks of fungi in groundwater sources of drinking water can produce taste and odor problems, and cause ill health in immunocompromised individuals. The groundwater treatment process is simple; generally, only disinfection is used in China. Efficient disinfection methods to control fungi are required. In the present study, we investigated the inactivation efficiency of 4 dominant genera of fungal spores (a Trichoderma sp., Acremonium sp. , Penicillium sp., and Cladosporium sp.) using ultraviolet irradiation (UV) and UV-based advanced oxidation processes, and explored the mechanisms of inactivation by monitoring the leakage of intracellular contents and changes in spore morphology. The inactivation of fungal spores is consistent with first-order Chick–Watson kinetics. The resistance of each of the fungi to UV ( Cladosporium sp. > Penicillium sp. > Acremonium sp. > Trichoderma sp.) was greater than that of E. coli , due to their larger sizes and more complex structures. UV/peroxymonosulfate (UV/PMS) treatment had a markedly better inactivation rate constant than UV alone. Furthermore, UV/PMS exhibited similar effects on fungal inactivation in phosphate buffer and in groundwater, whereas UV inactivation efficiency markedly decreased in groundwater. UV/PMS treatment resulted in cell wall and cell membrane damage, the leakage of intracellular contents, and the shriveling of fungal spores, due to the reactive radicals produced by the treatment. Thus, UV/PMS is a promising method to control fungi in drinking water sources. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1O 2 can be generated in the anodic oxidation of H 2 O 2 in the presence of Cl−. • 1O 2 was directly confirmed by a near infrared imaging system. • 1O 2 plays an important role in E. coli inactivation in the presence of 1 mM H 2 O 2. • The formation of Cl-DBPs was mitigated considerably in the presence of H 2 O 2. • The implications for electrochemical water treatment were discussed. Due to its potential applications in decentralized water treatment systems, electrochemical synthesis of H 2 O 2 for water decontamination has been widely investigated in recent years. In this study, it is found that the anodic oxidation of the residual H 2 O 2 in the presence of Cl− can be an efficient electrochemical disinfection technology to guarantee the microbiological safety of the treated water. H 2 O 2 can be oxidized by HOCl generated at the anode to form singlet oxygen (1O 2). 1O 2 has been recognized as an important disinfectant in solar disinfection (SODIS) but it has not yet been reported in electrochemical disinfection. The generation of 1O 2 was directly confirmed by the detection of 1O 2 monomol emission using a near infrared imaging system. The concentration of 1O 2 can reach up to 1.64 pM in the anodic oxidation of H 2 O 2 with Cl−. 1O 2 plays an important role in Escherichia coli (E. coli) inactivation, and HOCl only plays a subordinate role in the presence of 1 mM H 2 O 2 due to its low concentration. For example, by adding up the inactivation of E. coli by sole H 2 O 2 and micro-concentration HOCl together only attribute to about 2 log in 60 min but 1O 2 itself can account for about 3 log. Besides, the formation of the chlorinated disinfection by-products (Cl-DBPs) was mitigated considerably benefited from the fast reduction of HOCl by H 2 O 2. These findings have potential implications for H 2 O 2 -based decentralized water treatment systems and provide a novel strategy for electrochemical disinfection because electrochlorination is having the same problems that chlorination has. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1O 2 can be generated in the anodic oxidation of H 2 O 2 in the presence of Cl−. • 1O 2 was directly confirmed by a near infrared imaging system. • 1O 2 plays an important role in E. coli inactivation in the presence of 1 mM H 2 O 2. • The formation of Cl-DBPs was mitigated considerably in the presence of H 2 O 2. • The implications for electrochemical water treatment were discussed. Due to its potential applications in decentralized water treatment systems, electrochemical synthesis of H 2 O 2 for water decontamination has been widely investigated in recent years. In this study, it is found that the anodic oxidation of the residual H 2 O 2 in the presence of Cl− can be an efficient electrochemical disinfection technology to guarantee the microbiological safety of the treated water. H 2 O 2 can be oxidized by HOCl generated at the anode to form singlet oxygen (1O 2). 1O 2 has been recognized as an important disinfectant in solar disinfection (SODIS) but it has not yet been reported in electrochemical disinfection. The generation of 1O 2 was directly confirmed by the detection of 1O 2 monomol emission using a near infrared imaging system. The concentration of 1O 2 can reach up to 1.64 pM in the anodic oxidation of H 2 O 2 with Cl−. 1O 2 plays an important role in Escherichia coli (E. coli) inactivation, and HOCl only plays a subordinate role in the presence of 1 mM H 2 O 2 due to its low concentration. For example, by adding up the inactivation of E. coli by sole H 2 O 2 and micro-concentration HOCl together only attribute to about 2 log in 60 min but 1O 2 itself can account for about 3 log. Besides, the formation of the chlorinated disinfection by-products (Cl-DBPs) was mitigated considerably benefited from the fast reduction of HOCl by H 2 O 2. These findings have potential implications for H 2 O 2 -based decentralized water treatment systems and provide a novel strategy for electrochemical disinfection because electrochlorination is having the same problems that chlorination has. [ABSTRACT FROM AUTHOR]

Abstract: The isonicotinic acid (4-picolinic acid) served as a functional monomer firstly to prepare Mo(VI) oxy ion-imprinted particle (Mo-IIP) by the surface metal ion imprinting technique with a sol–gel process on the surface of amino-silica, and TEOS acted as a cross-linker monomer. The prepared Mo-IIP was characterized and its proper selectivity recognition ability was investigated by single binding experiments comparing to Mo(VI) oxy ion non-imprinted particle (Mo-NIP). Furthermore, the reuse was carried out. A possible imprinting mechanism was put forward for the Mo-IIP. The binding process fitted well to the pseudo-second-order kinetic model, the Langmuir model, and the Weber–Morris model. The results suggested that a multi-step with the film and intraparticle diffusion process might dominate this chemical sorption for Mo(VI) binding onto Mo-IIP. The Mo-IIP exhibited selectivity for Mo(VI) with a remarkably high binding capacity 2171.46μmolg−1, which was 7.6 times higher than that of the Mo-NIP. Such efficient selectivity might be due to the complexation ability of nitrogen atom in the 4-picolinic acid with supper memory sites after imprinting process. The excellent affinity and exclusive selectivity make the Mo-IIP become an potential material for Mo(VI) removal and concentration from the water environment. [Copyright &y& Elsevier]

• Facile in-situ biomineralization for preparing biocatalytic composite menbranes. • The membrane provides confined microenvironment for enzymatic oxidation of bisphenol A. • Ultra high bisphenol A removal efficiency of 98% under continuous flow is achieved. • Enhanced stability and reusability of biocatalytic membranes offered by the metal–organic framework scaffolds. The micropollutants in water sources are harmful to the aquatic environment and human health, and remain a significant challenge to be completely eliminated by conventional processes. Here, an original biocatalytic enzyme/metal–organic framework (MOF) composite membrane is developed to facilitate continuous and efficient removal of micropollutants from aqueous solution. In this work, an in-situ biomineralization strategy of simultaneous MOF (zeolitic imidazolate framework-8 or ZIF-8) nucleation and immobilization of horseradish peroxidase (HRP) is employed to form an enzymatic reactive HRP@ZIF-8 layer on modified ultrafiltration membrane. Such a hybrid structure design successfully integrates selective separation with stable enzymatic catalysis to prepare a reactive molecular sieve membrane, which realizes desirable decontamination performance toward micropollutants under low pressure. The as-prepared membrane sets a new record of bisphenol A (BPA) removal efficiency of 98% accompanied with high permeance (~33.32 L/m2.h.bar) at continuous mode. The removal mechanism is considered to be a combination of enhanced adsorption by MOFs enriching BPA molecules near the enzymes, catalytic oxidation by enzymes breaking the adsorption saturation limitation, and also membrane retention that reduced the enzymatic burden. In addition, the biocatalytic membrane displays enhanced stability and reusability due to the protection effect by the ZIF-8 exoskeleton, demonstrating good potential for stable and efficient removal of micropollutants for water treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • ABTS enhanced diclofenac elimination in Fe(II)/PAA process under acidic conditions. • ABTS remarkably accelerated the redox cycle of Fe(III)/Fe(II) in Fe(II)/PAA process. • Reactive species of FeIVO2+, R-O• and ABTS•+ existed in ABTS/Fe(II)/PAA process. • ABTS•+ was identified as primary reactive species for rapid elimination of diclofenac. • Trace Fe(II) was enough for rapid diclofenac elimination in ABTS/Fe(II)/PAA process. Fe(II)/peracetic acid (Fe(II)/PAA) process exhibits a great potential in abatement of micropollutants because of the fast reaction between Fe(II) and PAA. Similar to Fenton system, the slow reduction from Fe(III) to Fe(II) leads to the high dosage of Fe(II) in Fe(II)/PAA process. This study introduced 2,2′-azino-bis(3-ethylbenz- -othiazoline-6-sulfonate) (ABTS) as electron shuttle to improve the oxidation capacity of Fe(II)/PAA process by accelerating the redox cycle of Fe(III)/Fe(II). ABTS/Fe(II)/PAA process possessed high elimination efficiency of diclofenac in acidic conditions. Alcohols quenching experiments confirmed that ABTS•+ was the primary reactive species responsible for diclofenac elimination, although FeIVO2+ and carbon-centered radicals (R-O•) also existed in ABTS/Fe(II)/PAA process. ABTS•+ was generated via various pathways, including the reactions of ABTS with Fe(III), FeIVO2+ and R-O•. ABTS was not an ideal electron shuttle because R-O• could decompose partial ABTS•+ to sulfoxides and sulfones. Two possible degradation pathways of diclofenac were proposed based on the detected transformation products. ABTS/Fe(II)/PAA process was highly-efficient for diclofenac elimination in underground water and reservoir water, while high concentration of humic acid had inhibition effect on diclofenac degradation. The present study provides a promising way to alleviate the intrinsic drawbacks of Fe(II)/PAA process and might advance its potential application in water treatment. [ABSTRACT FROM AUTHOR]

• One-step polyphenol deposition strategy was applied to prepare multifunctional MF membranes. • Modified membranes with large pore sizes exhibited >6 log pathogenic reduction. • Metal ions were in-situ captured and reduced by polyphenol-based surface chemistry. • The membrane system showed effective biofouling prevention under gravity filtration. • Improved hydrophilicity and antimicrobial effects promote antibiofouling performance. In remote industrial areas, access to safe drinking water is often hindered by local water contamination and unreliable infrastructure. Hence, energy-effective water treatment and safe storage technology is vital and highly desirable to tackle complex water pollution caused by heavy metals and pathogenic contaminants for boundary circumstances. Here, we originally engineered a multifunctional gravity-driven membrane system to provide a household-level approach to pathogenic disinfection and biofouling prevention. Facile one-step polyphenol deposition strategy was applied on microporous membranes, tailoring the membrane surface with enhanced positive charge, favorable hydrophilicity and metal-binding ability. When applied in gravity-driven filtration of simulated multi-component wastewater containing heavy metals and pathogenic contaminants, the as-prepared membrane achieved >6 log pathogenic reduction. Metal ions could be in-situ captured and stabilized at membrane interface via natural binding and reduction by polyphenol-engineered surface chemistry, endowing ensuing membranes with improved antibacterial activity. By virtue of enhanced membrane surface properties and antimicrobial synergy, such engineered membrane platform showed potent efficacy in biofilm prevention with 97% reduced ATP content and easy permeation recovery (>90%) in cyclic operation. This study is promising for developing low-energy and easy-to-use membrane system to improve contaminated water sources in remote and underdeveloped areas at household level. [ABSTRACT FROM AUTHOR]

• The most efficient route was designed for 3D mesoporous α-Co(OH) 2 on Ni foam (NF). • Extraordinary catalytic activity of Co(OH) 2 /NF for peroxymonosulfate was observed. • The cobalt leaching was alleviated by the macroscopic Co(OH) 2 /NF. • The readily recyclable monolith catalyst benefits the practical application. Cobalt-based catalysts with high stability and facile recovery for heterogeneous peroxymonosulfate (PMS) activation are still rather sparse and therefore highly desirable. Herein, 3D mesoporous α-Co(OH) 2 nanosheets was created on robust nickel foam (NF) via facile electrodeposition approach at 6 mA/cm2 for only 400 s. Almost complete removal of phenol can be achieved within 7 min with a degradation rate of 0.39 min−1, 2 times higher than that with ever-prevalent Co 3 O 4 derived from direct calcination of α-Co(OH) 2 /NF. This can be attributed to the hydrotalcite-like hexagonal structure of α-Co(OH) 2 with large interlayer spacing for enhancing the catalytic performance. The low activation energy of Co(OH) 2 /NF (53.8 kJ/mol) indicates its lower reaction energy barrier for PMS activation. Moreover, the influences of electrodeposition parameters (i.e. current density, deposition time), PMS dosage, initial pH and coexisting anions (HCO 3 −, SO 4 2−, Cl−) on the phenol degradation were systematically evaluated. The recycling tests revealed the prominent stability of Co(OH) 2 /NF. The quenching tests verified that SO 4 − radicals acted as the predominant reactive species for phenol decomposition. The possible reaction mechanisms were proposed based on the intermediates identification. The findings of this work suggest the great potentials of the 3D macroscopic Co(OH) 2 /NF in water purification, and open up new avenues for scalable preparing recyclable heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

• TCs could be efficiently degraded by unactivated PMS. • Dimethylamino group and phenolic D ring of TCs were the main reaction sites. • Oxidation of TCs yielded O-addition, demethylation, and deamination products. • PMS oxidation could greatly eliminate the antibacterial activity of TCs. • Ca2+ and Mg2+ accelerated the oxidation of TCs by PMS due to their complexation effect. Tetracyclines (TCs) as a group of widely used antibiotics are frequent detected in aqueous environments. The transformation of tetracycline (TTC), oxytetracycline (OTC), and chlorotetracycline (CTC) as model TCs by unactivated peroxymonosulfate (PMS) during water treatment is examined in this study for the first time. Degradation of TCs by PMS showed a strong pH-dependency. The apparent second-order rate constants were in the range of 0.07–150.10 M−1s−1 (pH 5.0–10.0). Products analysis showed that PMS primarily reacted with TCs at their unprotonated dimethylamino group and deprotonated phenolic-diketone group, leading to the formation of O-addition, demethylation, and deamination products. Water hardness Ca2+ and Mg2+ appreciably accelerated the degradation of TCs by PMS due to their strong complexation with TCs, while chloride, bicarbonate, and natural organic matter at environmental relevant concentrations had negligible impacts. Transformation products of TCs showed negligible antibacterial activity comparing with the parent TCs by using Escherichia coli. as test bacteria. The degradation of TCs by PMS in real waters was appreciably faster than that in pure water, and the presence of background Ca2+ and Mg2+ in real waters accounted for this enhancing effect. Unactivated PMS exhibits great potential for the removal of TCs and their antibacterial activity from contaminated waters. [ABSTRACT FROM AUTHOR]