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Efficient removal of heavy metals complexed with organic ligands from water is still an important but challenging task now. Herein, a novel combined process, i.e., Fe(III)-displacement/UV degradation/alkaline precipitation (abbreviated as Fe(III)/UV/OH) was developed to remove copper–organic complexes from synthetic solution and real electroplating effluent, and other processes including alkaline precipitation, Fe(III)/OH, UV/OH were employed for comparison. By using the Fe(III)/UV/OH process, some typical Cu(II) complexes, such as Cu(II)–ethylenediaminetetraacetic acid (EDTA), Cu(II)–nitrilotriacetic acid (NTA), Cu(II)–citrate, Cu(II)–tartrate, and Cu(II)–sorbate, each at 19.2 mg Cu/L initially, were efficiently removed from synthetic solution with the residual Cu below 1 mg/L. Simultaneously, 30–48% of total organic carbon was eliminated with exception of Cu(II)–sorbate. Comparatively, the efficiency of other processes was much lower than the Fe(III)/UV/OH process. With Cu(II)–citrate as the model complex, the optimal conditions for the combined process were obtained as: initial pH for Fe(III) displacement, 1.8–5.4; molar ratio of [Fe]/[Cu], 4:1; UV irradiation, 10 min; precipitation pH, 6.6–13. The mechanism responsible for the process involved the liberation of Cu(II) ions from organic complexes as a result of Fe(III) displacement, decarboxylation of Fe(III)-ligand complexes subjected to UV irradiation, and final coprecipitation of Cu(II) and Fe(II)/Fe(III) ions. Up to 338.1 mg/L of Cu(II) in the electroplating effluent could be efficiently removed by the process with the residual Cu(II) below 1 mg/L and the removal efficiency of ∼99.8%, whereas direct precipitation by using NaOH could only result in total Cu(II) removal of ∼8.6%. In addition, sunlight could take the place of UV to achieve similar removal efficiency with longer irradiation time (90 min). [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical filtration using three-dimensional carbon nanotube (CNT) networks has been reported to increase the electrooxidation rate of aqueous pollutants due to convective mass transfer enhancements resulting from the flow through the electrode. In regards to the long term application of this novel electrochemical technology, electrode passivation is one of the most important challenges to overcome. Here, electrochemical filtration of aqueous phenol in a sodium sulfate electrolyte is utilized to investigate the primary passivation mechanisms and electrode regeneration methodologies, in which chronoamperometry and effluent total organic carbon measurements are utilized to monitor the passivation process in real-time, and electrochemical impedance spectroscopy, linear sweep voltammetry, and scanning electron microscopy are utilized to examine the CNT networks before passivation, after passivation and after regeneration. Finnaly, the carbon nanotube electrode passivation mechanisms and regeneration methods are discussed. Generally it is better choice to run system at higher potential in order to avoid generating polymer firstly other than regenerate complicatedly it after its passivation. Polymer formation can be prevented by application of an anode potential ≥2.1V, which can completely mineralize phenol to carbon dioxide etc. and prevent polymerization of phenol. If there is still a bit of polymer formed inevitably, washing electrodes with suitable solvents is an effective alternative. [Copyright &y& Elsevier]

Perfluoroalkyl substances (PFASs) are persistent and toxic to human health. It is demanding for high‐efficient and green technologies to remove PFASs from water. In this study, a novel PFAS treatment technology was developed, utilizing polytetrafluoroethylene (PTFE) particles (1–5 μm) as the catalyst and a low frequency ultrasound (US, 40 kHz, 0.3 W/cm2) for activation. Remarkably, this system can induce near‐complete defluorination for different structured PFASs. The underlying mechanism relies on contact electrification between PTFE and water, which induces cumulative electrons on PTFE surface, and creates a high surface voltage (tens of volts). Such high surface voltage can generate abundant reactive oxygen species (ROS, i.e. O2⋅−, HO⋅, etc.) and a strong interfacial electrostatic field (IEF of 109~1010 V/m). Consequently, the strong IEF significantly activates PFAS molecules and reduces the energy barrier of O2⋅− nucleophilic reaction. Simultaneously, the co‐existence of surface electrons (PTFE*(e−)) and HO⋅ enables synergetic reduction and oxidation of PFAS and its intermediates, leading to enhanced and thorough defluorination. The US/PTFE method shows compelling advantages of low energy consumption, zero chemical input, and few harmful intermediates. It offers a new and promising solution for effectively treating the PFAS‐contaminated drinking water. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFASs) are persistent and toxic to human health. It is demanding for high‐efficient and green technologies to remove PFASs from water. In this study, a novel PFAS treatment technology was developed, utilizing polytetrafluoroethylene (PTFE) particles (1–5 μm) as the catalyst and a low frequency ultrasound (US, 40 kHz, 0.3 W/cm2) for activation. Remarkably, this system can induce near‐complete defluorination for different structured PFASs. The underlying mechanism relies on contact electrification between PTFE and water, which induces cumulative electrons on PTFE surface, and creates a high surface voltage (tens of volts). Such high surface voltage can generate abundant reactive oxygen species (ROS, i.e. O2⋅−, HO⋅, etc.) and a strong interfacial electrostatic field (IEF of 109~1010 V/m). Consequently, the strong IEF significantly activates PFAS molecules and reduces the energy barrier of O2⋅− nucleophilic reaction. Simultaneously, the co‐existence of surface electrons (PTFE*(e−)) and HO⋅ enables synergetic reduction and oxidation of PFAS and its intermediates, leading to enhanced and thorough defluorination. The US/PTFE method shows compelling advantages of low energy consumption, zero chemical input, and few harmful intermediates. It offers a new and promising solution for effectively treating the PFAS‐contaminated drinking water. [ABSTRACT FROM AUTHOR]

Safe and clean freshwater harvesting from (organic‐containing) saline or wastewater holds great potential for mitigating water scarcity and pollution, but remains challenging. Herein, a floating photothermal/catalytic‐integrated interfacial micro‐evaporator (g‐C3N4@PANI/PS) is reported as a proof‐of‐concept multifunctional scavenger evaporator system (MSES) to achieve both solar‐driven complete desalination and organic degradation. The spherical porous lightweight polystyrene core, incorporated with a black surface functional layer (g‐C3N4@PANI), enables the hybrid micro‐evaporator to naturally float and thereby collectively self‐assemble under surface tension for interfacial evaporation, which achieves preeminent self‐cleaning for complete salt/solute separation and efficient organic photodegradation under rotation. Remarkably, the floating micro‐evaporator achieves a high solar‐vapor conversion efficiency of ≈90% with high interfacial energy localization and provides abundant active photocatalytic sites on the interface, which is further enhanced by interfacial photothermal cooperation. High photo‐driven degradation efficiencies of 99% for nonvolatile organic compounds (non‐VOC) bisphenol A and 95% for VOC phenol in wastewater are achieved. An outdoor comprehensive solar water treatment test toward organic‐containing high‐salinity sewage verifies the feasibility of MSES for sustainable freshwater harvesting (1.3 kg m−2 h−1), downstream salt recovery, and organic degradation. This strategy may inspire an integrated solution of water scarcity, clean energy, and environmental pollution toward carbon neutrality. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction sustainably produces ammonia and alleviates water pollution, yet is still challenging due to the kinetic mismatch and hydrogen evolution competition. Cu/Cu2O heterojunction is proven effective to break the rate‐determining NO3−‐to‐NO2− step for efficient NH3 conversion, while it is unstable due to electrochemical reconstruction. Here we report a programmable pulsed electrolysis strategy to achieve reliable Cu/Cu2O structure, where Cu is oxidized to CuO during oxidation pulse, then regenerating Cu/Cu2O upon reduction. Alloying with Ni further modulates hydrogen adsorption, which transfers from Ni/Ni(OH)2 to N‐containing intermediates on Cu/Cu2O, promoting NH3 formation with a high NO3−‐to‐NH3 Faraday efficiency (88.0±1.6 %, pH 12) and NH3 yield rate (583.6±2.4 μmol cm−2 h−1) under optimal pulsed conditions. This work provides new insights to in situ electrochemically regulate catalysts for NO3−‐to‐NH3 conversion. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction sustainably produces ammonia and alleviates water pollution, yet is still challenging due to the kinetic mismatch and hydrogen evolution competition. Cu/Cu2O heterojunction is proven effective to break the rate‐determining NO3−‐to‐NO2− step for efficient NH3 conversion, while it is unstable due to electrochemical reconstruction. Here we report a programmable pulsed electrolysis strategy to achieve reliable Cu/Cu2O structure, where Cu is oxidized to CuO during oxidation pulse, then regenerating Cu/Cu2O upon reduction. Alloying with Ni further modulates hydrogen adsorption, which transfers from Ni/Ni(OH)2 to N‐containing intermediates on Cu/Cu2O, promoting NH3 formation with a high NO3−‐to‐NH3 Faraday efficiency (88.0±1.6 %, pH 12) and NH3 yield rate (583.6±2.4 μmol cm−2 h−1) under optimal pulsed conditions. This work provides new insights to in situ electrochemically regulate catalysts for NO3−‐to‐NH3 conversion. [ABSTRACT FROM AUTHOR]

Abiotic transformation of graphene oxide (GO) in aquatic environments can markedly affect the fate, transport, and effects of GO. The authors observed that ferrous iron (Fe[II])-an environmentally abundant, mild reductant-can significantly affect the physicochemical properties of GO (examined by treating aqueous GO suspensions with Fe2+ at room temperature, with doses of 0.032 mM Fe2+ per mg/L, 0.08 mM Fe2+ per mg/L, and 0.32 mM Fe2+ per mg/L GO). Microscopy data showed stacking of GO nanosheets on Fe2+ treatment. Spectroscopy evidence (X-ray diffraction, Fourier transform infrared transmission, Raman and X-ray photoelectron spectroscopy) showed significant changes in GO surface O-functionalities, in terms of loss of epoxy and carbonyl groups but increase of carboxyl group. The reduction mechanisms were verified by treating model organic molecules (styrene oxide, p-benzoquinone, and benzoic acid) resembling O-containing fragments of GO macromolecules with Fe2+. With sedimentation and adsorption experiments (using bisphenol A as a model contaminant), the authors demonstrated that Fe2+ reduced GOs still maintained relatively high colloidal stability, whereas their adsorption affinities were significantly enhanced. Thus, reduction of GO by mild reductants might be of greater environmental concerns than by stronger reducing agents (e.g., N2H4 and S2-), because the latter can result in too significant losses of surface O-functionalities and colloidal stability of GO. This interesting aspect should be given consideration in the risk assessment of GO. Environ Toxicol Chem 2015;34:1975-1982. © 2015 SETAC [ABSTRACT FROM AUTHOR]

The long-time accumulation of low-rank coal can induce many environmental problems and severe waste of carbon resources. Flotation technology based on gas/liquid/solid interfacial interaction remains an efficient way to recovery combustible matter and realize clean utilization of coal. The traditional collector, kerosene, has demonstrated its low flotation efficiency and environmental hazards for low-rank coal. In this work, the kerosene was highly dispersed through emulsification with the biocompatible surfactant alkyl polyglucosides (APG) and optimized based on HLB of emulsifiers and emulsion phase diagrams. The emulsion with the mixture of hydrophilic APG and hydrophobic Span65 as emulsifier exhibits the strongest dispersibility and stability due to the formation of a stable composite molecular adsorption film of the mixed emulsifiers at oil/water interface. Compared with kerosene, the prepared emulsion collectors exhibited much higher flotation efficiency with combustible matter recovery increasing by 31.4% and simultaneously consumption of kerosene decreasing by 57.8% under optimal operation conditions. The hydrophobicity of coal surface is obviously enhanced after treatment by emulsion with the contact angle increasing from 26.6° to 71.7°. High-speed camera observation showed that only 76.59 ms was taken for the impinging emulsion droplet to adhere to low-rank coal surface followed with a faster spreading, indicating stronger interfacial interaction between emulsion collector and low-rank coal surface. The proposed 'bridging action' of emulsifier molecule between oxygen-containing groups at coal surface and kerosene in emulsion could remarkably enhance the differences in surface hydrophilicity between combustible coal and other contents, resulting in high flotation efficiency. These results constitute a substantial step forward in technical development for resource recycling of low-rank coal. [Display omitted] [ABSTRACT FROM AUTHOR]

• Piezoelectric ceramic membrane was used for oily wastewater treatment. • The inherent transmembrane pressure can induce a high membrane electric field. • In situ high membrane electric field enables demulsification. • DEP force ensures continuous membrane demulsification and oil/water separation. Recovering oil from oily wastewater is not only for economic gains but also for mitigating environmental pollution. However, demulsification of oil droplets stabilized with surfactants is challenging because of their low surface energy. Although the widely used oil/water separation membrane technologies based on size screening have attracted considerable attention in the past few decades, they are incapable of demulsification of stabilized oil emulsions and the membrane concentrates often require post-processing. Herein, the piezoelectric ceramic membrane (PCM), which can respond to the inherent transmembrane pressure in the pressure-driven membrane processes, was employed to transform hydraulic pressure pulses into electroactive responses to in situ demulsification. The pulsed transmembrane pressure on the PCM results in the generation of considerable rapid voltage oscillations over 3.2 V and a locally high electric field intensity of 7.2 × 107 V/m, which is capable of electrocoalescence with no additional stimuli or high voltage devices. Negative dielectrophoresis (DEP) force occurred in this membrane process and repelled the large size of oil after demulsification away from the PCM surface, ensuring continuous membrane demulsification and oil/water separation. Overall, PCM provides a further opportunity to develop an environmentally friendly and energy-saving electroresponsive membrane technology for practical applications in wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Mesoporous wall-structured TiO2 on reduced graphene oxide (RGO) nanosheets were successfully fabricated through a simple hydrothermal process without any surfactants and annealed at 400 °C for 2 h under argon. The obtained mesoporous structured TiO2-RGO composites had a high surface area (99 0307 m2 g−1) and exhibited excellent electrochemical cycling (a reversible capacity of 260 mAh g−1 at 1.2 C and 180 mAh g−1 at 5 C after 400 cycles), demonstrating it to be a promising method for the development of high-performance Li-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to develop a novel integrated active capping system and to investigate its efficiency in the remediation of nitrobenzene-contaminated sediment. An integrated Fe(0)–sorbent–microorganism remediation system was proposed as an in situ active capping technique to remediate nitrobenzene-contaminated sediment. In this system, nitrobenzene was reduced to aniline by Fe(0), which has a much better biodegradability. The sorption capacity and structural properties of cinder was measured to examine its applicability as the sorbent and matrix for this integrated capping system. Indigenous microorganisms from Songhuajiang River sediment, which was contaminated by nitrobenzene and aniline in Chinese Petrochemical Explosion in Jilin, were acquired one month after the explosion and used in this active capping system to degrade nitrobenzene and its reduced product, aniline. A bench-scale remediation experiment was conducted on a mimicked nitrobenzene-contaminated sediment to investigate the efficiency of the integrated capping system and the synergistic effects of the combined components in the active capping system. The results show that this integrated active capping system can effectively block the release of target pollutants into the upper-layer water and remove the compounds from the environment. [ABSTRACT FROM AUTHOR]

Abstract: In this study, photodegradation of 2,4-dichlorophenol (2,4-DCP) in aerated aqueous solution at pH 13 in the presence of hydrogen peroxide catalyzed by polydivinylbenzene-supported zinc phthalocyanine (PDVB-ZnPc) prepared from chloromethylated polydivinylbenzene and zinc phthalocyanine via a Friedel–Crafts reaction has been investigated. The reaction intermediates were identified by gas chromatography–mass spectrometry (GC–MS). The reactive oxygen species involved in the reaction were determined by electron paramagnetic resonance (EPR) technique. Based on the experimental results obtained, PDVB-ZnPc was found to be effective for removing and mineralizing the toxic 2,4-DCP in aqueous solution. The removal yield amounted to 98% after 4h of irradiation. The reaction followed pseudo-first-order kinetics, and was well fitted into the Langmuir–Hinshelwood-type equation. The optimal concentration of PDVB-ZnPc was 1.0g/l. The reaction intermediates were some biodegradable organic acids which were subsequently mineralized to CO3 2− and Cl− in alkaline solution. Hydroxyl radical and superoxide anion radical other than singlet oxygen were probably generated during the photodegradation of 2,4-DCP in our reaction system. [Copyright &y& Elsevier]

The employment of electrochemical technology in membrane filtration promises high separation efficiency with minimal membrane fouling. Herein, we fabricated single cobalt atom and nitrogen atom codoped graphene (NG-Co) as a conductive membrane, and showed that it achieved 99.5% rejection at a small voltage of 2.5 V and exhibited excellent reusability. The turnover frequency of the single Co site was about 13.5 times larger than that of traditional Co-based nanocatalysts, because the single Co site served as the key electrochemical active site to degrade the organic pollutants, while the nitrogen-doped groups of graphene served as efficient binding sites for the immobilization of the single Co site to improve the intrinsic catalytic activity of the Co sites. This study has important implications for the design of graphene-based conductive membranes in the electrochemical remediation of wastewater. • Single cobalt grafted onto nitrogen-doped graphene as a superior conductive membrane. • Electrochemical degradation of >90% of methylene blue over repeated cycles. • Single Co immobilized by nitrogen-doped graphene were key active sites. • Mild synthesis conditions of NG-Co eases large-scale synthesis. • NG-Co outperformed NG, G-Co and traditional Co 3 O 4 -based catalysts. [ABSTRACT FROM AUTHOR]

Porous graphene represents promising electrocatalysts or substrates of composite electrocatalysts for various electrochemical reactions, and is well-established for renewable energy conversion and environmental remediation. Unfortunately, the lack of comprehensive understanding on the active sites of porous graphene hinders the further development of high-performance electrocatalysts. Herein, porous graphene was established for electrochemical filtration of wastewater, with results indicating that porous graphene exhibited excellent electrochemical activity in terms of high efficiency of oxidation or reduction of organic pollutants. It was experimentally and theoretically demonstrated that the –OH groups generated on the edge of porous graphene served as the active sites for the electrocatalytic reactions. The augmentation of –OH groups at the edges of graphene benefited the inner-sphere electron transfer of the electrocatalytic reactions, improving the electron transfer rates by nearly four times (from 0.034 s−1 to 0.135 s−1). Through providing these fundamental insights into the role of the active sites on the pores of porous graphene, this work furnishes future directives for the design of porous graphene-based electrocatalysts. Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ce201 enabled catalytic H 2 O 2 oxidation and sorption for synergistic As(III) removal. • Stoichiometric H 2 O 2 (H 2 O 2 /As(III) = 1–2) greatly enhanced As(III) removal by Ce201. • As(III) was oxidized by Ce-OOH and resultant As(V) was fixed by –N+(CH 3) 3 groups. • As-laden Ce-201 could be well regenerated by NaOH−NaCl solution for cyclic runs. • Fixed-bed working capacity of Ce-201/H 2 O 2 was 20 times HFO-201 or twice of Ce-201. Abstract Aiming at efficient As(III) removal, a millimetric nanocomposite Ce-201, with dual functionalities of catalytic H 2 O 2 oxidation and sorption, was synthesized by confined growth of hydrous nanoceria in macroporous anion-exchanger host D201. The removal of As(III) by Ce-201 was significantly enhanced by H 2 O 2 at stoichiometric dosage (H 2 O 2 /As(III) molar ratio = 1–2), during which the catalytic oxidation of As(III) into As(V) played a vital role. The surface peroxide species formed on the surface of the embedded hydrous nanoceria induced by H 2 O 2 were proved the predominant reactive species for As(III) oxidation, and the resultant As(V) was mostly sequestered by the quaternary ammonium groups of the D201 host. The removal of As(III) by Ce-201/H 2 O 2 was favorable over wide pH range of 5–9, whilst the presence of chloride, carbonate (up to 10 mM), sulfate, silicate, nitrate (up to 1 mM), and humic acid (up to 30 mg DOC/L) posed negligible adverse effect on As(III) removal. The As-laden Ce-201 could be well regenerated by NaOH−NaCl binary solution for sustainable utilization without significant capacity loss. In fixed-bed mode, the working capacity of Ce-201 with H 2 O 2 spiked into the influent at trace level (2.67 μM) for continuous As(III) removal (∼6500 BV) was over twenty times that of the classic nanocomposite HFO-201 or twice of Ce-201 without H 2 O 2. Therefore, the Ce-201/H 2 O 2 technique showed great potential for full scale application of highly efficient decontamination of As(III) from water. [ABSTRACT FROM AUTHOR]

Abstract Sulfate ions (SO 4 2−) are ubiquitous in aqueous environments and are generally considered to be inert due to their chemical stability. For the first time, we found that SO 4 2− can be activated into SO 4 2--type radicals (e.g., SO 3 -, SO 5 -, SO 4 -) in the presence of phenolic compounds under simulated or natural solar irradiation. In turn, the radicals promoted the transformation and mineralization of phenolic compounds compared to that in the absence of SO 4 2− with reaction rate constants ranging from 0.008 h−1 to 0.021 h−1. In addition, the activation mechanisms of inert SO 4 2− in the photochemical transformation of phenolic compounds were elucidated. A hydrated electron (e aq −) is first generated during the photolysis of phenolic compounds and is the most important step in the activation of SO 4 2−. Then, the e aq − reduces SO 4 2− to SO 3 2−, and SO 3 2− is further photochemical activated to become a reactive species (e.g., e aq − and SO 3 -), which can evolve into strong oxidants (e.g., SO 5 - and SO 4 -), via a series of radical chain reactions. These oxidants are responsible for the enhanced phenolic compound degradation. The photochemical activation of seemingly inert SO 4 2− sheds new light on studies on the transport, transformation and environmental impact of matter (e.g., phenolic compounds) in specific water environments and provides a novel strategy for the generation of SO 4 - and photochemical removal of phenolic pollutants. Graphical abstract Image 1 Highlights • SO 4 2− can be activated into SO 4 2− radicals in the presence of phenolic compounds. • The activation mechanism for SO 4 2− activation were investigated in waterbody. • This study provides a novel strategy for the generation of SO 4 2--related radicals. [ABSTRACT FROM AUTHOR]

Enhanced removal of trace toxic metals (ppm level) from high-salinity wastewater is crucial to ensure water safety but still a challenging task. In this study, we fabricated a new hybrid ultrafiltration membrane (PAA/ZIF-8/PVDF) by immobilizing zeolitic imidazolate framework-8 (ZIF-8) particles onto the surface of trimesoyl chloride (TMC)-modified polyvinylidene fluoride (PVDF) membrane under protection of polyacrylic acid (PAA) layer. The resultant PAA/ZIF-8/PVDF membrane exhibited relatively high water flux of 460 L·m −2  h −1 and outstanding nickel ion (Ni(II)) capacity (219.09 mg/g) from a synthetic high-salinity ([Na + ] = 15000 mg/L) wastewater. X-ray photoelectron spectroscopic studies revealed that preferable Ni(II) uptake was mainly attributed to the specific interaction between Ni(II) and hydroxyl groups on ZIF-8 frameworks and carboxyl groups in PAA layer as well. Compared to PAA, ZIF-8 could selectively bind Ni(II) with negligible effect exerted by concentrated sodium ion. The filtration study showed that the 12.56-cm 2 membrane could effectively treat 5.76 L high-salinity wastewater ([Ni(II) 0  = 2 mg/L, [Na + ] 0  = 15000 mg/L) to conspicuously reduce Ni(II) below the maximum contaminant level of China, 0.1 mg/L. Moreover, the hybrid membrane could be regenerated by HCl-NaCl solution (pH = 5.5) for repeated use under direct current electric field. Generally speaking, the newly developed ZIF-8 hybrid ultrafiltration membrane showed a very promising potential in enhanced removal of toxic metals from high-salinity wastewater treatment. [ABSTRACT FROM AUTHOR]

In this study we reported that the presence of functionalized multi-walled carbon nanotubes (FCNT-H) would greatly enhance the degradation of atrazine (ATZ), a model contaminant, in the Fe(III)-mediated Fenton-like system. Efficient ATZ degradation (>90%) was achieved within 30 min in the presence of 20 mg.L −1 FCNT-H, 2.0 mg.L −1 Fe(III), and 170 mg.L −1 H 2 O 2 , whereas negligible ATZ degradation occurred in FCNT-H free system. The structure and surface chemistry of FCNT-H and other CNTs were well characterized. The formed active species were determined based on ESR analysis, and the mass balance of Fe species during the reaction was monitored. In particular, a new method based on ferrozine complexation was proposed to track the formed Fe(II). The results indicated that ATZ was mainly degraded by the generated hydroxyl radical (HO·), and Fe(III)/Fe(II) cycling was still the rate-limiting step. Besides a small fraction of Fe(III) reduced by FCNT-H, a new pathway was revealed for fast reduction of most Fe(III), i.e., reaction of FCNT-H-Fe(III) complexes with H 2 O 2 . Comparison of different CNTs-mediated Fe(III)/H 2 O 2 systems indicated that such enhanced effect of CNTs mainly resulted from the surface carboxyl group instead of hydroxyl and carbonyl group. Combined with X-ray photoelectron spectroscopy (XPS) analysis, the electron density migration from Fe(III) to FCNT-H possibly resulted in the fast reduction of FCNT-H-Fe(III) complexes by H 2 O 2 . This study enables better understanding the enhanced Fe(III)-mediated Fenton-like reaction in the presence of MWCNTs and thus, will shed new light on how to develop more efficient similar Fenton systems via Fe(III) complexation. [ABSTRACT FROM AUTHOR]

Efficient removal of heavy metal-EDTA complexes from water remains a challenge because of their good solubility and chemical stability. Herein, we employed a proprietary process, i.e., the Fe(III) displacement/UV irradiation/alkaline precipitation (denoted as Fe(III)/UV/OH), to enable an efficient removal of Cu(II)-EDTA complex from 19.2 mg Cu(II)/L to <1 mg Cu(II)/L. The combined process includes Fe(III) replacement with the complexed Cu(II) to form Fe(III)-EDTA and release the free Cu(II), UV-mediated catalytic decarboxylation of EDTA to form amine ligands and reduction of Fe(III) to Fe(II), and the final removal of Cu(II) through precipitation. The in situ formed Fe(II) is crucial to the final Cu(II) removal because it tends to form stable complexes with amine ligands (EDTA and its decarboxylation products), thereby inhibiting their re-complexation with the released Cu(II) and facilitating the formation of copper precipitates. Consequently, the methods capable of prolonging the life of Fe(II), e.g., increasing the Fe(III) addition or direct addition of Fe(II) into the Cu(II)-EDTA solution and deoxygenating the solution, could dramatically enhance the final Cu(II) removal. We also optimized the operational conditions of the process at the initial Cu(II)-EDTA of 19.2 mg Cu(II)/L. [ABSTRACT FROM AUTHOR]

Adsorption is a classical process widely used in industry and environmental protection, and the regeneration of exhausted adsorbents, as the reverse process of adsorption, is vital to achieving a sustainable adsorption process. Chemical and thermal regeneration, which feature high costs and environmental side effects, are classical but not environmentally friendly methods. Herein, a new regeneration method based on an electrochemical process using graphene aerogel (GA) as a model conductive adsorbent was proposed. First, 3D GA was prepared to adsorb organic and inorganic pollutants, avoiding the inconvenience of using powdered graphene. Then, the exhausted GA was cleaned by the electrochemical desorption and degradation of adsorbed organic pollutants if undesired and the electrorepulsion of adsorbed metal ions in the absence of any additional chemicals, showing a high processing capability of 1.21 L g-1 GA h-1 and low energy consumption (~0.2 kWh m~3 solution). The mechanisms involved in the electrochemistry-induced desorption process cover a decline in the GA adsorption performance depended on the electrochemically adjustable surface charge conditions, and the further repulsion and migration of adsorbates is subject to the strong in situ electric field. This work has important implications for the development of environmentally friendly regeneration processes and qualified adsorbents as well as the application of a green and efficient regeneration concept for traditional adsorption processes. [ABSTRACT FROM AUTHOR]

Iron is one of the most abundant elements in aquatic environments, and plays important roles in the fate and transport of environmental contaminants. Previous studies on the photochemical properties of Fe(III) species have largely focused on complexes formed between Fe(III) and environmental ligands such as natural organic matter (NOM) under UV irradiation, whereas the potentially important roles of hydrolysis species of Fe(III) in Fe(III)-mediated photo-transformation of environmental contaminants under solar light are not fully understood. In this study, the solar light-driven photochemical activities of hydrolysis species of Fe(III) were further explored, using a system containing only 0.5 mM Fe 2 (SO 4 ) 3 and bisphenol A. The important role of colloidal [Fe(OH) 3 ] m , formed from the hydrolysis of Fe 3+ , as a core photochemical species of Fe(III) was proposed and verified. Interestingly, O 2 − , rather than OH, was identified (via electron spin resonance) as the key active radical responsible for the degradation of bisphenol A. We propose that unlike Fe(OH) 2+ , which under UV irradiation can yield OH (Fe(OH) 2+ + hv → Fe 2+ + OH), colloidal [Fe(OH) 3 ] m produces O 2 − even in sunlight ([Fe(OH) 3 ] m + 2O 2 + hv → Fe(II) + 2O 2 − + H 2 O). The fact that Fe(III) can produce strong radicals in sunlight may have important environmental implications. [ABSTRACT FROM AUTHOR]

• A novel hierarchical cubic Li x TiO 2 -based hollow Li-ion sieve was constructed. • A prelithiation concept at a mild temperature is proposed to engineer active Li+ sites. • ZIF-8 with unique 6-ring window is employed as Li+ channel for selective recovery. • The hollow TiO 2 -based core–shell hybrid yields high Li+ capture capacity against competing ions. Sustainable lithium supply significantly matters the healthy development of electric vehicles markets. Selective adsorption plays an important role in aqueous lithium recovery due to low energy consumption and easy processing. We here report a prelithiation concept to generate active Li+ sites in TiO 2 forming Li x TiO 2 at a mild temperature for lithium recovery. A hollow protonated Li x TiO 2 matrix with nanosheets surface was built to provide abundant active sites for specific Li+ capture with fast matter transfer. And a biomimetic metal–organic framework (ZIF-8) gate layer, acting as Li+ channel, was engineered to regulate cation solvation structure for selective transport of Li+. Consequently, the resultant TiO 2 -based hybrid lithium-ion sieve demonstrates fast and homogenous Li+ chemisorption with a high Li+ uptake capacity (∼14 mg g−1 for 24 h at pH = 12), high Li+ selectivity against competing cations in both simulated and natural brine, and acceptable reusability in simulated brine, indicating further application potential. [ABSTRACT FROM AUTHOR]

Metal oxides are often anchored to graphene materials to achieve greater contaminant removal efficiency. To date, the enhanced performance has mainly been attributed to the role of graphene materials as a conductor for electron transfer. Herein, we report a new mechanism via which graphene materials enhance oxidation of organic contaminants by metal oxides. Specifically, Mn 3 O 4 –rGO nanocomposites (Mn 3 O 4 nanoparticles anchored to reduced graphene oxide (rGO) nanosheets) enhanced oxidation of 1-naphthylamine (used here as a reaction probe) compared to bare Mn 3 O 4 . Spectroscopic analyses (X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy) show that the rGO component of Mn 3 O 4 –rGO was further reduced during the oxidation of 1-naphthylamine, although rGO reduction was not the result of direct interaction with 1-naphthylamine. We postulate that rGO improved the oxidation efficiency of anchored Mn 3 O 4 by re-oxidizing Mn(II) formed from the reaction between Mn 3 O 4 and 1-naphthylamine, thereby regenerating the surface-associated oxidant Mn(III). The proposed role of rGO was verified by separate experiments demonstrating its ability to oxidize dissolved Mn(II) to Mn(III), which subsequently can oxidize 1-naphthylamine. The role of dissolved oxygen in re-oxidizing Mn(II) was ruled out by anoxic (N 2 -purged) control experiments showing similar results as O 2 -sparged tests. Opposite pH effects on the oxidation efficiency of Mn 3 O 4 –rGO versus bare Mn 3 O 4 were also observed, corroborating the proposed mechanism because higher pH facilitates oxidation of surface-associated Mn(II) even though it lowers the oxidation potential of Mn 3 O 4 . Overall, these findings may guide the development of novel metal oxide–graphene nanocomposites for contaminant removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • More efficient Joule heating production were obtained at higher voltage. • Nearly 100% Benzoic acid (BA) was desorpted from CNTs film at an optimium voltage. • Electrothermal regeneration has extremely lower energy consumption. Thermal-desorption has been considered as an environmentally friendly approach to regenerate the exhausted adsorbents to achieve a sustainable adsorption process. However, the traditional thermal desorption method suffers from the demanding contradiction between the desorption efficiency and energy consumption. Herein, we developed an efficient and economical thermal-desorption strategy based on the Joule heating by employing a three-dimensional carbon nanotubes (CNTs) film as the model adsorbent. The features of CNTs film with negative temperature coefficient endow the impressive heat production for the electrical resistance decreased from 341.0 Ω at 25.7 °C to 36.7 Ω at 76.5 °C. The desorption ratio of target pollutant (i.e., benzoic acid) in the continuous Joule heat induced thermal desorption process could be reached to 93.2% with the energy consumption of 0.25 kW h, which is two orders of magnitude lower than that in the indirect thermal desorption process for one ton of wastewater at the specified scale. This study proposed a green and energy-efficient strategy for thermal regeneration, and provide a method guidance for the development of green regeneration technology. [ABSTRACT FROM AUTHOR]

The leachate generated from the sanitary landfill or incineration poses serious environmental threats and it's difficultly disposed due to its complexity containing high concentration of organic matters and inorganic salts etc. Membrane technology stands out as a potential solution for leachate because of its beneficial advantages. Nanofiltration (NF) can reject organic compounds and separate divalent ions from mixed salts, which alleviates fouling and increases separation efficiency and flux of reverse osmosis (RO) in the popular combined processes (MBR-NF/RO) applicable for leachates. However, NF is often subject to low water permeance and membrane fouling for traditional polyamide thin film composite (PA-TFC) membranes. This work develops a high-performance NF membrane by grafting bipyridinium derivative monomer (BBD), an alternative antibacterial by interfering with the bacterial metabolism and reproduction and a hydrophilic compound endowing membrane hydrophilicity, onto PA-TFC membranes through the esterification reaction toward the leachate treatment. Resultantly, the BBD-TFC membrane achieves a reasonably high pure water permeability of 31.6 ± 2.1 L m−2 h−1 bar−1, ∼ 4 times higher than that of the pristine polyamide membrane. Notably, the resultant membrane exhibits excellent antifouling and antibacterial properties in the treatment of the leachate benefiting from the more hydrophilic surface and negative potential on BBD-TFC. Meanwhile, high rejection ratio of divalent ions and organic matter (R > 95%) was also attained companying with high separation efficiency of divalent/monovalent ions. The current work may provide an effective strategy to design high performance NF membranes for the leachate treatment or other wastewater treatment. [Display omitted] • TFC NF membranes grafted by bipyridinium derivative monomer (BBD) was developed. • Water flux of BBD-TFC was ∼ 4 times higher than that of the pristine TFC membrane. • BBD-TFC exhibited excellent antifouling and antibacterial properties toward leachate treatment. • Organic matter was highly retained companying with high separation of mono/divalent ions. [ABSTRACT FROM AUTHOR]

The energy-induced peroxydisulfate (PDS) activation is a green and effective approach for pollutant degradation, while the huge energy consumption would significantly increase the cost of wastewater treatment. In this study, by taking carbon nanotubes (CNTs) membrane as the light to heat (LTH) conversion materials, we developed a photothermal PDS activation process for degradation of organic contaminants in a flow-by reactor, with hydroxyl radicals (•OH) and sulfate radicals (SO 4 •−) as the main reactive species. This system has excellent in-situ LTH conversion performance and heat transfer ability. As a result, various pollutants are degraded with an efficiency higher than 90%. More importantly, the LTH device exhibits satisfying stability and could be used for pollutant (i.e., methyl orange (MO)) removal under solar irradiation. In addition, some important factors (i.e., irradiation distance, residence time, solution pH, and PDS dosage) that might significantly influence the removal efficiency of pollutants are optimized. This work provides a novel perspective for the activation of PDS via CNTs as photothermal materials for pollutant degradation with a flow-by reactor. [Display omitted] • CNTs membrane exhibits excellent light to heat conversion property and thermal conductivity. • In-situ PDS activation and pollutant degradation are achieved in a flow-by reactor. • Pollutants can be effectively removed under solar irradiation. • The operation factors are systematically optimized. [ABSTRACT FROM AUTHOR]

Magnetic stir bars are routinely used by most of researchers in the fields of chemistry, biology and environment etc. An incredible phenomenon, in which the magnetic stirring increased reaction rate by tens of times under ultrasound irradiation, impelled us to explore roles of magnetic stirring. Unexpectedly, the thimbleful nano PTFE particles, from shell of magnetic stir bar, were exfoliated during magnetic stirring and account for ultrahigh tribocatalytic and piezocatalytic activities under ultrasonic irradiation. Reactive oxygen species (ROS), such as hydroxyl radical (OH), superoxide radicals (O 2 −) and singlet oxygen (1O 2) were generated in the present of PTFE under ultrasound irradiation, which is desired in the pollution control. The newly discovered PTFE activity, against the conventional wisdom that PTFE is inert, which also reminds the researchers that the trace amount of PTFE ground during magnetic stirring may inadvertently botch our experiments and introduce false positive results, especially involving routine magnetic stirring and ultrasound irradiation operation in laboratory. In addition, the safety and inertness of PTFE may require further review in PTFE-based commercial, industrial and biomedical settings. [Display omitted] • The thimbleful nano PTFE particles were exfoliated from magnetic stir bar during stirring. • Ultrasound can induce PTFE to generated strong aqueous reactive oxygen species. • The safety and inertness of PTFE may require further review. [ABSTRACT FROM AUTHOR]

Magnetic stir bars are routinely used by most of researchers in the fields of chemistry, biology and environment etc. An incredible phenomenon, in which the magnetic stirring increased reaction rate by tens of times under ultrasound irradiation, impelled us to explore roles of magnetic stirring. Unexpectedly, the thimbleful nano PTFE particles, from shell of magnetic stir bar, were exfoliated during magnetic stirring and account for ultrahigh tribocatalytic and piezocatalytic activities under ultrasonic irradiation. Reactive oxygen species (ROS), such as hydroxyl radical (OH), superoxide radicals (O 2 −) and singlet oxygen (1O 2) were generated in the present of PTFE under ultrasound irradiation, which is desired in the pollution control. The newly discovered PTFE activity, against the conventional wisdom that PTFE is inert, which also reminds the researchers that the trace amount of PTFE ground during magnetic stirring may inadvertently botch our experiments and introduce false positive results, especially involving routine magnetic stirring and ultrasound irradiation operation in laboratory. In addition, the safety and inertness of PTFE may require further review in PTFE-based commercial, industrial and biomedical settings. [Display omitted] • The thimbleful nano PTFE particles were exfoliated from magnetic stir bar during stirring. • Ultrasound can induce PTFE to generated strong aqueous reactive oxygen species. • The safety and inertness of PTFE may require further review. [ABSTRACT FROM AUTHOR]

Despite of the advanced progress made in membrane techniques, cleaning of membrane fouling remains challenging in membrane filtration process, especially during water purification, chemical and food production, etc. Existing techniques for alleviating membrane fouling such as ultrasound treatment can achieve limited improvement. Thus, developing more environmental-friendly, low-cost, and convenient cleaning strategies is highly desired. Here, we propose a self-cleaning concept of self-vibrating membrane with piezoelectric characteristics and demonstrate its feasibility in membrane anti-fouling. A well-designed piezoelectric membrane (ZnO-CNT/PVDF) has been constructed, where the in situ synthesized zinc oxide (ZnO) nanoparticles are served as a nucleation seed promoting the β-phase formation of poly (vinylidene fluoride) (PVDF) and the percolation network structure is formed by carbon nanotubes (CNTs) to achieve piezoelectric vibration. Encouragingly, the piezoelectric membrane resonated to external AC stimulus at 8 kHz and showed the highest vibration amplitude. The resultant ZnO-CNT/PVDF membrane demonstrated strong antifouling properties and excellent permeation recovery efficiency of 98.0% (AC, 12.5 V, 8 kHz), compared to 58.5% of the control ZnO-CNT/PVDF (0 V) and 53.0% of bare PVDF membrane (AC, 12.5 V, 8 kHz). The improved antifouling capacity benefited from that piezoelectric vibration could reduce the filtration resistances caused by concentration polarization (CP) layer and membrane fouling. Moreover, this antifouling mode of piezoelectric vibration is effective toward different charged foulants. This work demonstrates a novel and effective self-cleaning strategy for employing piezoelectric membrane in high-efficiency anti-fouling. [Display omitted] ● An in situ synthesized piezoelectric ZnO-CNT/PVDF membrane was proposed. ● ZnO-CNT/PVDF showed strong antifouling property with water recovery ratio of 98.0%. ● Piezoelectric vibration made R cp and R f of ZnO-CNT/PVDF membrane decrease. ● Piezoelectric vibration was an effective cleaning strategy against different charged foulants. [ABSTRACT FROM AUTHOR]

In this paper, sphere-like NiS was synthesized by solvothermal method. Furthermore, the electrocatalytic performance of NiS was tested as counter cells (CEs) of Dye-sensitized solar cells (DSSCs). Resulting from the inherent catalytic property and charge transfer ability, NiS exhibited excellent electrocatalytic performance towards I − / I 3 - redox reaction. And the power conversion efficiency of NiS CE (PCE=7.39%) was better than that of commercial Pt CE (PCE=7.06%). [ABSTRACT FROM AUTHOR]

• Novel charged membranes were firstly proposed based on spontaneous polarization of ferroelectric BaTiO 3. • Ferroelectric membrane was featured with high surface charge and well antifouling performance. • Ferroelectric membrane showed excellent permeability and As(V) rejection. Membrane filtration is widely applied, but often subject to a trade-off between permeability and selectivity, an inherent challenge in membrane processes. Charged membranes are a promising alternative to address this challenge. Here, ferroelectric BaTiO 3 nanoparticles, with a spontaneous electric polarization, were assembled into the traditional polyamide nanofiltration membranes by interfacial polymerization then charged by corona poling. Importantly, charges of ferroelectric BaTiO 3 nanoparticles sealed in polymers were hardly affected by ambient aqueous environment. The polarized ferroelectric membrane (TFN-mBTO-E) showed higher permeability (2.4 and 1.5 times) and favorable rejection ratio about 97% for arsenic removal, a strictly controlled contaminant, compared with common membranes and unpolarized TFN-mBTO membranes, due to strong hydrophilicity and increased surface potential derived from ferroelectric charges. Thereby, it could provide new insight into charged membrane, laying a foundation for the application of ferroelectric materials in membrane filtration. [ABSTRACT FROM AUTHOR]

• A solid lithiothermic reduction method is used to produce oxygen vacancies in P25. • Plasmonic metals of Ag and Cu nanoparticles are deposited onto the reduced P25. • Synergistic effect of oxygen vacancies and plasmon-induced hot carriers. • High NO 3 − removal efficiency of 93% and N 2 selectivity of 68% yielded without HCOOH. Photoreduction has been proven effective to remove NO 3 − from water, as NO 3 − has severely damaged water quality over decades. However, the typical photoreduction of NO 3 − usually requires sufficient hole scavengers (mostly formic acid) to produce strong reducing carboxyl radical (CO 2 −) species for the elementary conversion of NO 3 −. The excessive employment of hole scavengers increases the cost of water treatment, and further results in secondary chemical pollution. Here, a novel hole-scavenger-free efficient NO 3 − photoreduction route is developed by using a novel oxygen-deficient photocatalyst (R-P25@Ag/Cu nanoparticles). Graded oxygen vacancies are introduced into P25 nanocrystals via lithiothermic reduction approach, significantly promoting the photocatalytic capability. Subsequently, bimetal (Ag and Cu) nanoparticles are stepwise anchored onto the reduced P25 particles to improve the separation of the photogenerated carriers from the reduced P25 particles; more importantly, the plasmonic nanoparticles trigger the initial elementary step of NO 3 − reduction to NO 3 2− [E0(NO 3 −/ NO 3 2−) = −0.89 V versus SHE] with plasmon-induced hot carriers. Consequently, the optimized R-P25@Ag/Cu catalyst shows an outstanding NO 3 − removal performance with a high removal efficiency of 93% and a N 2 selectivity of 68% (mercury lamp, 180 min) by a synergistic effect without hole scavengers. [ABSTRACT FROM AUTHOR]

Selective reduction of nitrate to N 2 is attractive but still a difficult challenge in the water treatment field. Herein, we established a flow-through electrochemical system packed with polymeric beads supported nZVI (nZVI@D201) for selective nitrate reduction. Consequently, efficient nitrate reduction in the flow mode was achieved on nZVI@D201 under electrochemical regulation with N 2 selectivity of up to 95% for at least 60 h. Otherwise, nZVI was gradually exhausted after 20 h, and the product was mainly the undesired NH 4 +. Through a series of comparative experiments, we clarified that the enhanced nitrate reduction on nZVI under electrochemical regulation was mainly attributed to electrons (from cathode) and active hydrogen ([H]) rather than the previously speculated H 2. Combining the characterizations of nZVI during nitrate reduction by X-ray diffraction and X-ray photoelectron spectrometry, we found that nitrate reduction under electrochemical regulation was mediated by nZVI along with the resultant Fe0@Fe x O y -Fe(II) structure and was sustained by electrons (from cathode) and [H] via the in situ reduction of Fe(III) back to Fe(II). Meanwhile, the undesirable product NH 4 + was efficiently oxidized to N 2 by the active chlorine generated on the anode. This study not only clarifies the mechanism of enhanced nitrate reduction on nZVI via electrochemical regulation but also advances the technological coupling of nZVI reduction with electrochemistry. Image 1 • Selective nitrate reduction was achieved in a flow-through electrochemical system. • Nitrate was reduced with N 2 selectivity up to 95% via electrochemical regulation. • Enhanced nitrate reduction was attributed to electrons (from cathode) and [H]. • The study advances technological coupling of nZVI reduction with electrochemistry. [ABSTRACT FROM AUTHOR]

• Simultaneous removal of Cr(VI) and MB was achieved even in high saline medium. • The synergistic removal of Cr(VI) and MB was realized in coexisting system. • Cr(VI) and MB was classifiably recovered via electrochemically assisted desorption. Heavy metal ions, dyes and high concentrations of salt are three kinds of representative compounds in the wastewater produced from dyeing processes. An integrated technical process with multifunctional adsorbents for the simultaneous removal of pollutants, e.g., inorganic heavy metal ions and organic dyes, is highly desired. Moreover, classification of the recycled adsorbates on the exhausted adsorbents is also important and necessary. Herein, we have developed a new strategy to synergistically remove and electrochemically classify the recycled Cr(VI) and dyes from synthetic dyeing wastewater. First, polyaniline (PANI) was used to decorate the spherical resin (PS) by one-step in situ polymerization, and the as-synthesized composite (PANI@PS) was used as an adsorbent for simultaneous removal of Cr(VI) and methylene blue (MB) in high saline medium mainly based on PANI and PS, respectively. The synergistic adsorption removal capacities of Cr(VI) and MB on PANI@PS reached 183.0 mg Cr(VI) g−1 PANI and 40.3 mg MB g−1 PANI@PS in a coexisting system, in contrast to 94.0 mg Cr(VI) g−1 PANI and 27.5 mg MB g−1 PANI@PS in a single-component system. These increases are attributed to the additional adsorption sites and electrostatic attractions between the adsorbed Cr(VI)(−) and MB(+). Noticeably, the adsorbed Cr(VI)(−) and MB(+) can be recovered and classified via electrochemically assisted desorption, with a maximum recovery ratio of 90.3% (Cr(VI)(−)) and 91.9% (MB(+)). This study is of great significance for introducing novel adsorbent composites for the simultaneous removal and classified recovery of specific coexisting pollutants. [ABSTRACT FROM AUTHOR]

Charged ultrafiltration (UF) membranes can repel electrically charged molecules that are smaller than the size of the membrane pores and display high rejection of solutes, high flux, and low operation pressures compared to uncharged UF, nanofiltration (NF) and reverse osmosis (RO). Here, a charged UF membrane composite (PANI/PVDF) was prepared and regulated via electrochemically reversible control in portions of amine/imine functional groups of PANI. As a result, the permeability and rejection ratios of CR2− on charged PANI/PVDF, with PVDF as a control, increased from 19.6 to a maximum of 183.3 L m−2 h−1 bar−1 and from 3.4% to 74%, which expands the trade-off confine benefited from surface potential change from −12.21 mV to −25.26 mV, furtherly, the rejection ratio of CR2− on PANI/PVDF reached up to 93% via the electrochemical regulation. Finally, a fixed-charge model was built that well describes the steric and electric repulsion effects on membrane performance and the important roles of the electrochemically controllable surface charge. Moreover, the contour map of rejection ratios containing the ratio of molecular size vs the average pore size of the membrane (r/R = 0.2–1.0) and the zeta potential (−10 to −60 mV) were taken into account, which can be used to visually understand the rejection performance of membranes. This model is also appropriate for varying molecular sizes and for molecules with different charges. Our work opens a new horizon for the design of electrochemically controllable charged membranes to remove charged compounds. Image 1 • Charged UF membranes can repel electrically charged dyes with high rejection of solutes and high flux. • The charges play a key role in rejecting charged molecules smaller than the membrane pores diameter. • Fixed-charge model that combines both electrostatic repulsion and static sieving effects was established. • Our work opens a new horizon for the design of electrochemically controllable charged membranes. [ABSTRACT FROM AUTHOR]