Search

[Display omitted] • Novel concentration-pressure co-driven AAME for solute separation was elucidated. • The Δ P can promote the organics transmembrane mass transfer in AAME. • Volatilization-diffusion occurred for volatile compound in porous membrane. • Increases in r and Δ P would increase organics permeation and membrane wetting risk. • The permeation of SDS was only observed after membrane wetting with NaCl invasion. Aqueous-aqueous membrane extraction (AAME) has great potential to revolutionize industrial wastewater treatment, achieving the value-added organic product recovery with low operation cost. Here, we first reported the feasibility, performance and mechanism of selective separation of three typical organics (phenol, ethanol and sodium dodecyl sulfate (SDS)) from salty solution not only in common concentration-difference driven but also in novel concentration-pressure-difference co-driven AAME using porous polyvinylidene fluoride (PVDF), non-porous polydimethylsiloxane (PDMS) and composite PVDF/PDMS membranes. In concentration-difference driven AAME, phenol and ethanol were separated from NaCl solution through three membranes, while SDS permeation only occurred on wetted porous PVDF membrane. Note that, volatile phenol and ethanol transported across the porous PVDF and composite PVDF/PDMS via volatilization-diffusion and solution-diffusion. In concentration-pressure-difference co-driven AAME, highest phenol (10.7) and ethanol fluxes (34.7 g m2 h−1) were obtained through composite PVDF/PDMS membrane (Δ P = 3 kPa) and PVDF membrane (Δ P = 9 kPa), respectively, with complete NaCl rejection. These data showed suitable membrane and high Δ P were beneficial to promote organics transmembrane transport. However, overload Δ P increased the membrane wetting risk on porous membranes. Once membrane was wetted, organics transmembrane mass transfer was simplified to direct pore-flow filtration. These findings provide a crucial step toward understanding the potential of AAME in resource recovery from industrial wastewater. [ABSTRACT FROM AUTHOR]

Highlights • Electrospun TPU/PDMS/PMMA membrane exhibited hydrophobicity and organophilicity. • Membrane tensile strength increased 12.6 times after adding TPU in electrospinning. • Self-bundled fiber yarns and point-bonded structure improved mechanical property. • MARS was developed with ETPPM to achieve phenol separation from saline wastewater. Abstract Electrospun poly(dimethyl siloxane)/poly(methyl methacrylate) (PDMS/PMMA) membrane (EPPM) is an emerging material in membrane aromatic recovery system (MARS) for phenol separation from saline wastewater. However, its application and performance in MARS are hindered by poor mechanical property. To solve this issue, thermoplastic polyurethanes (TPU) was mixed with PDMS and PMMA to fabricate novel electrospun TPU/PDMS/PMMA membrane (ETPPM). Membrane morphologies showed that intrinsically random oriented fibers of EPPM were gradually changed into the self-bundled fiber yarns with point-bonded structure, which led to the tensile strength and elongation at break of ETPPM-3 increased 12.6 times and 89.9%, respectively after 1.5 g TPU addition. Furthermore, ETPPM-3 presented a simultaneous organophilic and hydrophobic surface with phenol static contact angle of 0° and NaCl solution static contact angle of 143.4°, indicating its potential in phenol separation from saline wastewater. After 24 h MARS operation, 498.3 mg L−1 of phenol was separated from the initial phenol saline wastewater (2.0 g L−1 phenol and 10.0 g L−1 NaCl) with a conductivity increase of 21.2 µs cm−1. As a result, 24.9% of phenol recovery and 99.86% of salt rejection were achieved with mean phenol mass transfer coefficient of 7.3 × 10−7 m s−1 and flux of 4.4 × 10−4 kg m−2 s−1. [ABSTRACT FROM AUTHOR]

Phenol recovery from phenol-laden saline wastewater plays an important role in the waste reclamation and pollution control. A membrane aromatic recovery system-like membrane contactor (MARS-like membrane contactor) was set up in this study using electrospun polydimethylsiloxane/polymethyl methacrylate (PDMS/PMMA) membrane with 0.0048 m 2 effective area to separate phenol from saline wastewater. Phenol and water contact angles of 0° and 162° were achieved on this membrane surface simultaneously, indicating its potential in the separation of phenol and water-soluble salt. Feed solution (500 mL) of 0.90 L/h and receiving solution (500 mL) of 1.26 L/h were investigated to be the optimum conditions for phenol separation, which corresponds to the employed Reynolds number of 14.6 and 20.5. During 108-h continuous separation for feed solution (2.0 g/L phenol, 10.0 g/L NaCl) under room temperature (20 °C), 42.6% of phenol was recycled in receiving solution with a salt rejection of 99.95%. Meanwhile, the mean phenol mass transfer coefficient ( K ov ) was 6.7 × 10 −7  m s −1 . As a membrane-based process, though the permeated phenol increased with the increase of phenol concentration in feed solution, the phenol recovery ratio was determined by the membrane properties rather than the pollutant concentrations. Phenol was found to permeate this membrane via adsorption, diffusion and desorption, and therefore, the membrane fouling generated from pore blockage in other membrane separation processes was totally avoided. [ABSTRACT FROM AUTHOR]

Membrane bioreactor with non-woven fabric membranes (NWMBR) is developing into a suitable method for anaerobic ammonium oxidation (anammox). As a carrier, non-woven fabric membrane divided total biomass into biofilm and suspended flocs gradually. Total nitrogen removal efficiency was maintained around 82.6% under nitrogen loading rate of 567.4 mg N/L/d after 260 days operation. Second-order substrate removal and Stover-Kincannon models were successfully used to simulate the nitrogen removal performance in NWMBR. High-throughput sequence was employed to elucidate the underlying microbial community dynamics. Candidatus Brocadia , Kuenenia , Jettenia were detected to affirm the dominant status of anammox microorganisms and 98.2% of anammox microorganisms distributed in biofilm. In addition, abundances of functional genes ( hzs , nirK ) in biofilm and suspended flocs were assessed by quantitative PCR to further investigate the coexistence of anammox and other microorganisms. Potential nitrogen removal pathways were established according to relevant nitrogen removal performance and microbial community. [ABSTRACT FROM AUTHOR]

The major challenges for electrospun membranes used in direct contact membrane distillation (DCMD) process are insufficient pore wetting resistance related with hydrophobicity and pore structure of membrane surface. A novel super-hydrophobization method containing first coating TiO 2 nanoparticles on membrane surface by the low temperature hydrothermal process and then the TiO 2 coated membrane being fluorosilanized with low surface energy material of 1 H , 1 H , 2 H , 2 H -perfluorododecyl trichlorosilane (FTCS) was employed to modify the virgin polyvinylidene fluoride electrospun nanofiber membrane (PVDF ENM). Results showed that this TiO 2 -FTCS modified membrane possessed high hydrophobicity (157.1°), high mean roughness (4.63 μm), considerable wetting resistance (158 kPa), well-distributed pore size (0.81 μm), reasonable surface porosity (57%) and modest membrane thickness (55 μm). These combined properties made the modified PVDF ENM an attractive candidate for DCMD. High flux and stable desalination performances were achieved during short-term DCMD process (73.4 LMH permeate flux, 99.99% salt rejection) using 3.5 wt% NaCl solution. Long-term DCMD process with actual reverse osmosis brine as feed solution also showed high performance (40.5 LMH, 99.98%). These results exceeded those of commercial PVDF membrane and unmodified PVDF ENM significantly, suggesting the potential for PVDF ENM in DCMD applications. [ABSTRACT FROM AUTHOR]

An extractive membrane bioreactor (EMBR) for phenol-laden saline wastewater was set up in this study to investigate the variations of phenol removal, extracellular polymeric substance (EPS) release and microbial community dynamics. The gradual release of phenol and the total separation of salt were achieved by silicon rubber tube membrane. Only phenol (55.6–273.9 mg/L) was extracted into microorganism unit from wastewaters containing 1.0–5.0 g/L phenol and 35.0 g/L NaCl. After 82 d of EMBR operation, maximal 273.9 mg/L of phenol was removed in EMBR. Low concentration of phenol in wastewater (2.5 g/L) played a favorable effect on the microbial community structure, community and dynamics. The enumeration of Proteobacteria (30,499 sequences) significantly increased with more released EPS (82.82 mg/gSS) to absorb and degrade phenol, compared to the virgin data without phenol addition. However, high concentration of phenol showed adverse effects on EPS release, microbial abundance and biodiversity. [ABSTRACT FROM AUTHOR]

Considerable efforts have been devoted to finding economic and simple preparation methods for polydimethylsiloxane (PDMS) superhydrophobic membrane in past decades. This study provides a simple method to electrospin PDMS membrane using poly (methyl methacrylate) (PMMA) as carrier polymer. Effects of PMMA concentration, PDMS/PMMA mass ratio and main parameters of electrospinning process (voltage and injection rate) were investigated to obtain superhydrophobic membrane with high water contact angle (WCA). A highest WCA of 163° could be obtained on the membrane surface fabricated by electrospinning solution containing PDMS: PMMA: tetrahydrofuran (THF): N , N -dimethylformamide (DMF) (mass ratio 1: 1: 8.88: 9.48) under applied voltage of 11 kV and injection rate of 0.1 mm/min. The superhydrophobic PDMS/PMMA membrane was further applied in membrane distillation process for desalination, and a high permeation flux of 39.61 L/m 2 h and an excellent salt rejection of 99.96% were achieved during long-term MD process (24 h). [ABSTRACT FROM AUTHOR]

The separation of hardness ions such as calcium and magnesium from hard water can improve water quality, which is important but technically challenging. Nanofiltration (NF) has attracted much attention because of its efficiency, environmental friendliness and low cost. However, common NF membranes with a singly (either positively or negatively) charged layer have insufficient water softening capacity. In this work, two types of dual-layer Janus charged polyamide NF membranes composed of oppositely charged inner and outer layers were developed for the first time by sequential electrospray polymerization strategy for efficient water softening. The effect of the microstructure of the dually charged barrier layer on the separation performance of divalent salt ions was explored. Detailed mechanistic studies revealed that the microstructure of the outer layer of the barrier layer played a crucial role in the ion separation of the Janus membrane due to its control of the reverse transport of ions. Janus charged polyamide NF membrane with a loose outer layer exhibited better water softening performance (93.6% of hardness removed) compared to the singly charged NF membranes due to the simultaneous dual electrostatic effect and no ion reverse transport confinement. This Janus charged NF membrane also possessed good antifouling performance, mainly due to its negatively charged outer layers. The mechanistic insights gained in this study reveal the huge potential of microstructural design toward high-performance Janus charged NF membranes, and provide important guidance on the future development of high-efficiency water softening NF membranes. [Display omitted] • Janus membranes are firstly prepared via a sequential electrospray polymerization. • Janus membranes exhibit high rejection for both divalent cations and anions. • The transport and separation mechanism of Janus NF membranes are revealed. • Janus membranes exhibit a high hardness removal for water softening. [ABSTRACT FROM AUTHOR]

To further expand the application of anammox biotechnology, a novel zero-valent iron-assembled upflow anaerobic sludge bed reactor was employed to strengthen anammox performance under low temperature and shock load. Packed with sponge iron and polyester sponge, this novel reactor could speed up the recovery of anammox activity in 12 days and improve the adaptability of anammox bacteria at the temperature of 10-15 °C. The high nitrogen loading rate of 1109.2 mg N/L/day could be adapted in 27 days and the new nitrogen pathway under the effect of sponge iron was clarified by batch experiment. Moreover, the real-time quantitative PCR analysis and Illumina MiSeq sequencing verified the dominant status of Candidatus Kuenenia stuttgartiensis and planctomycete KSU-1, as well as demonstrated the positive role of sponge iron on anammox microorganisms' proliferation. The findings might be beneficial to popularize anammox-related processes in municipal and industrial wastewater engineering. [ABSTRACT FROM AUTHOR]

Excessive discharge of saline antibiotics wastewater into aquatic ecosystem is one crucial environmental issue facing the world today. Herein, an eco-friendly nanofiltration (NF) membrane was fabricated based on coordination complexes of tannic acid and ferric ions (TA-Fe) to selectively separate antibiotic and monovalent salt. Optimal membrane with Fe/TA molar ratio of 3/1 and coordination time of 60 s exhibited Zeta potential of −26.0 mV (pH = 7), water contact angle of 45.5o and pore radius of 0.36 nm. Consequently, TA-Fe@M3-T60 membrane showed high ciprofloxacin/NaCl rejection ratio of ~5.9 and considerable water permeability of 20.6 ± 1.2 LMH. Besides, relatively high rejection rates were obtained for ofloxacin (94.1 ± 2.2 %) and ciprofloxacin (91.9 ± 2.5 %), while rejection rate for trimethoprim was much lower (68.2 ± 4.1 %). Effects of static/dynamic membrane adsorption of antibiotics on subsequent removal performance were investigated for the first time. Rejection rate improvements of 7.4–15.2 % were observed on pristine membrane compared with pre-adsorbed membrane in short-term NF process. Electrostatic shielding experiment and rejection rate prediction further distinguished the contributions of steric hindrance, electrostatic interaction and membrane adsorption on antibiotics removal, especially antibiotics in zwitterionic form at pH = 7. The findings of this work imply that this newly developed NF membrane has great potential for efficient treatment of antibiotics-contaminated wastewater. • TA-Fe NF membrane showed high antibiotic/NaCl selectivity and desirable water flux. • Different charged antibiotics removal by TA-Fe NF membrane was explored in detail. • Membrane adsorption effectively promoted the antibiotic removal before equilibrium. • Electrostatic shielding and rejection prediction distinguished removal mechanism. [ABSTRACT FROM AUTHOR]

Thin-film composite polyamide (TFC-PA) nanofiltration membrane is promising in heavy metal removal due to its excellent performance and high economic benefits. However, the common interfacial polymerization (IP) fabrication method requires abundant toxic and harmful solvents, causing harm to the environment and humans. Therefore, novel green, low-carbon and sustainable fabrication methods are urgently needed. Here, we reported a sustainable electrospray polymerization (SEP) technique for TFC-PA membrane preparation via electrospray featuring no toxic solvent, near-complete monomer conversion, and zero waste liquid discharge. In this process, 2-methyl-tetrahydrofuran and ethanol were used as green solvents, and its greenness was assessed by green metrics and toxicity bioassays. Physical features and physicochemical properties of SEP membranes were characterized by SEM, TEM, AFM and XPS. Membranes with different surface charges and pore sizes could be tailored by varying the monomer concentration. The optimal membrane exhibited excellent removal efficiency of toxic heavy metal ions, in which the rejection rates of Cu2+ and Ni2+ were higher than 97.0 %. In addition, the permeability and salt rejection of SEP membranes were better than those of IP membranes. Our sustainable electrospray polymerization method provides a versatile green platform for fabricating TFC membranes and may facilitate the development of sustainable nanofiltration membranes. [Display omitted] • TFC-PA NF membranes are first prepared by sustainable electrospray polymerization. • Membrane fabrication greenness was assessed by green metrics and toxicity bioassays. • Membranes surface charge and pore size could be tailored via monomer concentration. • Optimal membrane shows excellent heavy metal removal and acceptable permeate flux. [ABSTRACT FROM AUTHOR]

[Display omitted] • CMP wastewater was used as a coagulant to accelerate suspended particles settling. • SiO 2 and CaF 2 particles would be attracted by electrostatic interaction. • Increasing n(SiO 2 :CaF 2) reduced the attractive force between membrane and foulant. • Intermediate blocking and cake filtration were observed at n(SiO 2 :CaF 2) = 5 and 8. • The fluoride in UF permeate qualified the median fluoride effluent standard. Fluoride and silica contamination in water is a worldwide issue due to the wastewater discharge from semiconductor industry. Coagulation-ultrafiltration (UF) process is commonly used to treat semiconductor wastewaters, but it requires excessive amounts of coagulant/flocculant. In this study, a clean coagulation-UF process using chemical mechanical polishing (CMP) wastewater as a coagulant to treat fluoride-containing wastewater was firstly proposed. The fluoride-containing wastewater, CMP wastewater, mixed fluoride-containing wastewater and CMP wastewater, and mixed fluoride-containing wastewater and polyaluminium chloride/polyacrylamide were compared to investigate turbidity removal efficiency, fluoride removal efficiency and membrane fouling resistance. The negatively charged SiO 2 particles in CMP wastewater were found to be adsorbed on the positively charged CaF 2 particles surface through electrostatic interaction. Results indicated that CMP wastewater provided a superior turbidity removal efficiency and a minimal membrane fouling resistance compared to conventional coagulant. After UF filtration, the fluoride concentration and turbidity were 2.09 mg L−1 and 0 NTU, respectively, which met the median fluoride effluent standard. The extended Derjaguin-Landau-Verwey-Overbeek theory showed that increasing molar ratio of SiO 2 to CaF 2 improved the interfacial free energy between membrane and suspended particles, thus mitigating membrane fouling. This clean design principle and strategy will broaden the sustainability of coagulation-UF process for wastewater treatment. [ABSTRACT FROM AUTHOR]

High voltage operation is effective to improve salt adsorption capacity (SAC) of capacitive deionization (CDI), while this will cause performance loss during long-term operation. Herein, to address this issue, we report a simple approach to prepare novel membrane coating electrode (MCE) that polyvinyl alcohol/polyethyleneimine membrane was deposited onto activated carbon fiber (ACF) and glutaraldehyde (GA) was used for crosslinking. Compared with ACF (SAC: 13.2–20.9 mg/g, charge efficiency: 63.6%–43.9%), MCE with optimized 5 wt% GA concentration (MCE (5)) showed an improved SAC from 14.6 to 28.4 mg/g and stable charge efficiency at 80.2% when voltage increased from 0.8 V to high voltage of 1.8 V due to suppressed anode oxidation. After forty cycles experiments at 1.8 V, SAC retention of ACF declined to 71.6% caused by degradation of electrode properties, while SAC retention of MCE (5) increased to 124.7%. The deposited membrane was found to act as a barrier and inhibitor to restrict ACF oxidation, and conversions of N-containing groups and reduced charge transfer resistance of cycled MCE (5) led to superb long-term performance. It is reasonable to believe that our work provides new strategy for enhancing CDI performance by using newly developed MCE. [Display omitted] • A novel MCE was prepared firstly by depositing PVA/PEI membrane onto ACF. • MCE (5) exhibited a high SAC and improved SAC retention under a high voltage. • MCE (5) showed a stable E pzc and reduced charge transfer resistance during cycling. • PVA/PEI membrane acted as a barrier and inhibitor to suppress ACF oxidation. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is a promising hybrid thermal/membrane desalination process to treat high salinity industrial wastewater with near-complete rejection of nonvolatile solutes. However, MD membrane still suffers the membrane wetting, which largely affects the desalination performance. In this study, a facile method includes one-step in-situ growth of ZnO nanorods and dip coating of low surface energy 1H,1H,2H,2H -perfluorodecytriethoxysilane (PDTS) was applied to fabricate omniphobic membrane (FZnO-PVDF) with excellent anti-wetting performance. The anti-wetting performance of FZnO-PVDF membrane was systemically evaluated by treating pure water, feed with surfactant and sparingly soluble salts for the first time. Theoretical analysis such as numerical simulation, dynamic liquid entry pressure (LEP) changes and nucleation condition was carried out to explain its anti-wetting mechanism. Results showed that FZnO-PVDF membrane displayed high contact angles towards water droplets with (∼121.1°) or without alcohol (∼164.9°), and low sliding angle for water (10.6°). The resultant membrane not only exhibited excellent resistance for surfactant-induced membrane wetting towards 0.6 mM sodium dodecyl sulfate (SDS) due to its enhanced LEP value (225 kPa), but also remarkable resistance for scaling-induced membrane wetting because of the high energy barrier for CaSO 4 heterogeneous nucleation (34.2 mJ mol−1) and slip boundary condition of membrane. This study provides valuable insights for fabricating omniphobic membrane and comprehending its anti-wetting property in MD application. [Display omitted] • Omniphobic FZnO-PVDF membrane was prepared by facile ZnO growth and fluorination. • Numerical simulation indicated falling droplet rebounded from omniphobic surface. • Enhanced dynamic LEP led to great resistance for anti surfactant-induced wetting. • High ΔG heterogeneous and slip boundary endowed high anti scaling-induced wetting. [ABSTRACT FROM AUTHOR]

The high concentration of fluoride in aqueous, which exacerbated by the discharged wastewater from semiconductor, electroplating, metallurgical and ceramics industries, has gone far beyond the World Health Organization (WHO) standard and seriously affected the health of human life. This study aims to validate the deep removal of fluoride from high fluoride-containing wastewater by using an integrated precipitation/crystallization/ultrafiltration (UF)/reverse osmosis (RO) system. The system enables an extremely low residual fluoride concentration (down to 0.25 mg L−1) qualified WHO standard, which was much lower than those of other reported membrane-based processes. In particular, the application of crystallization rather than conventional coagulation/flocculation was demonstrated to be effective in reducing fluoride, turbidity and sludge water content. Membrane fouling analysis indicated that UF membrane scaling was attributed to the CaF 2 particles deposition at recovery rates of 70%–90%. RO membrane fouling behaviors were identified at recovery rate of 50% (organic fouling), 70% (inorganic scaling occurred and organic fouling) and 80% (inorganic scaling and organic fouling). Meanwhile, UF/RO membrane scaling/fouling could be removed by pure water cleaning (UF) and Na 2 CO 3 /NaOH/HCl cleaning (RO). Results of this work shall provide useful information on the application of a precipitation/crystallization/UF/RO system to purify and recover high fluoride-containing wastewater. [Display omitted] ● A new integrated system for fluoride-containing wastewater treatment was developed. ● Crystallization process reduced fluoride, turbidity and sludge water content. ● UF/RO fouling behaviors were identified along the permeate recovery rates. ● Residual fluoride in integrated system effluent qualified WHO standard. [ABSTRACT FROM AUTHOR]

[Display omitted] • AAO process with novel amPAN adsorbent was developed to treat composite wastewater. • Effects of aniline and antimony on substrate removal in AAO process were explored. • Release of PN was more susceptible than PS in presence of aniline and antimony. • Evolved microbial community was responsible for substrate removal improvement. • COD (94.4%), NH 4 +-N (92.6%), TN (76.4%) and TP (93.4%) were removed in Stage 3. There has been increasing concern over the mixed discharge of municipal-textile composite wastewater, which remains challenging for typical wastewater treatment plant (WWTP) using anaerobic-anoxic–oxic process (AAO). Highly-toxic aniline and antimony, typical co-contaminants in textile wastewater, usually lead to increased chemical oxygen demand (COD) in influent and deteriorated effluent quality. Amidoxime-modified polyacrylonitrile (amPAN) adsorbent was prepared and added to adsorb antimony and facilitate substrate removal. With amPAN dosage at 6.0 g L−1 in oxic bioreactor, 64.2 ± 5.6% of antimony was removed from influent. Extracellular polymeric substance release was simultaneously changed with residual antimony concentration. Meanwhile, amPAN promoted the proliferation of Proteobacteria , Bacteroidetes and Epsilonbacteraeota serving as microorganism carrier. As a result, removal efficiencies of COD (94.4 ± 0.6%), ammonium (NH 4 +-N, 92.6 ± 3.3%), total nitrogen (TN, 76.4 ± 6.3%) and total phosphorus (TP, 93.4 ± 2.1%) were enhanced to meet Class 1A discharge standard in China. These results indicate that AAO with amPAN is promising for municipal-textile composite wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amidoxime-PAN/PLA nanofiber sphere supported TiO 2 (TiO 2 @NFS) was synthesized. • TiO 2 @NFS showed efficient simultaneous removal of hazardous aniline and Sb(V). • Numerous mesopores promoted "dark reaction" adsorption prior to photodegradation. • Amidoxime groups increased adsorption sites for Sb(V). Removal of organic aniline and antimony (Sb(V)) in textile wastewater was usually studied individually in cost-ineffective way. In this study, novel amidoxime-PAN/PLA nanofiber sphere (NFS) supported TiO 2 (TiO 2 @NFS) was fabricated to remove aniline and Sb(V) simultaneously. Results of scanning electron microscope (SEM), fourier infrared spectrometer (FTIR), X-ray diffractometer (XRD) and photoluminescence spectrometer (PL) demonstrated that TiO 2 nanoparticles were uniformly dispersed and immobilized on NFS. With 6 h of UV light exposure, aniline and Sb(V) reductions of TiO 2 @NFS were 86.3% and 78.5%, respectively, both of which were higher than those of plain commercial TiO 2 (48.6% and 6.3%). This was attributed to that numerous mesopores in TiO 2 @NFS could facilitate "dark reaction" adsorption prior to photodegradation for aniline and abundant amidoxime groups could increase adsorption sites for Sb(V). Kinetics for aniline and Sb(V) removal could be well modeled by Langmuir-Hinshelwood and pseudo-second-order equation, respectively, according to high correlation coefficients (R2 greater than 0.90). In addition, TiO 2 @NFS could well deposit after 10 min of standing, indicating excellent sedimentation performance. Recycling experiment showed good recycling stability of TiO 2 @NFS. These findings indicated that aniline and Sb(V) were promising to be simultaneously removed from textile wastewater by novel TiO 2 @NFS via photodegradation coupled with adsorption technology. [ABSTRACT FROM AUTHOR]

Amidoxime-polyacrylonitrile (APAN) nanofiber possesses advantages of adsorbing heavy metals for abundant amidoxime groups. However, it easily suffers from poor mechanical property caused by fiber contraction during amidoximation process. Inspired by high mechanical strength of reinforced concrete, we embedded stiff polylactic acid (PLA) skeletons into PAN matrix to prepare reinforced-concrete structured nanofiber sphere (APAN/PLA NFS) through solution blending. Preparation parameters including polymer concentration and PAN/PLA ratio were optimized as 4.0% and 1:1, and coarse sphere surface, numerous mesopores and large pore volume (19.3 mL/g) were endowed. Scanning electron microscope results showed restricted fiber contraction with nitrile conversion of 58.1%. APAN/PLA NFS showed robust compressive strength of 3.28 MPa with strain of 80%, and X-ray diffraction and differential scanning calorimeter analysis revealed that crystalline PLA reinforced non-crystalline PAN through molecule-level compatibility. Compared with plain APAN sphere, Sb(V) adsorption from water for APAN/PLA NFS showed better performance with superhigh capacity of 949.7 mg/g and fast rate (equilibrium time of 2 h), which was owing to abundant mesopores preserved by PLA skeletons. These findings indicated that PLA was a promising skeletal candidate which could protect APAN from fiber contraction during amidoximation process and could strongly expand adsorption capacity of APAN for heavy metals. [Display omitted] • Novel reinforced-concrete structured nanofiber sphere (APAN/PLA NFS) was prepared. • APAN/PLA NFS showed restricted fiber contraction during amidoximation process. • Reinforcing mechanism was explored using XRD and DSC analysis. • APAN/PLA NFS showed superhigh adsorption capacity of 949.7 mg/g for Sb(V). [ABSTRACT FROM AUTHOR]

High-performance thin film composite polyamide (TFC-PA) membranes with controllable structure and transport properties are of great significance. However, TFC-PA membranes prepared by interfacial polymerization are far from ideal due to their quick and uncontrollable reaction process. In this study, we reported a novel strategy to fabricate TFC-PA membranes via an electrospray interface-less polymerization (EILP) technique with a miscible solvent system. The miscible solvent system facilitated both the stable and fine spraying of monomer solutions and the efficient polymerization of monomers, and thus resulting in the formation of a smooth and defect-free PA skin layer. Moreover, the crosslinking degree and thickness of the EILP membrane skin layer could be controlled easily by regulating the concentration and dose of sprayed monomers. Attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential and mean effective pore size were employed to characterize the EILP membrane and clarify the separation mechanism. The optimum EILP membrane showed excellent filtration performance with a high water flux of up to 17.7 L m−2 h−1 bar−1, high salt rejection (98.2% of Na 2 SO 4) and complete dye rejection for Congo red. This study provides new insights into the understanding of electrospray procedures and enlightens the design and manufacture of advanced membrane materials through electrospray. [Display omitted] • TFC-PA membranes were firstly prepared by electrospray interface-less polymerization. • Electrospray process parameters were systematically investigated for optimization. • Controllable growth of PA skin layer with nanometer-level precision was achieved. • The optimal membrane exhibited high removal rates of dye/salt. [ABSTRACT FROM AUTHOR]

The traditional adsorbents for antimonate (Sb(V)) in industrial effluent suffered from poor adsorption capacity due to the lack of pores or adsorption sites. Three-dimensional (3D) amidoxime-polyacrylonitrile sphere (APANS) with hierarchical pores and abundant amidoxime groups was fabricated via nanoscale thermally induced phase separation (TIPS). The effects of fabrication parameters including diluent type, PAN concentration and amidoximation time on pore structure were studied with scanning electron microscopy (SEM), mercury intrusion instrument (MIP), fourier transform infrared spectrophotometer (FT-IR) and X-ray photoelectron spectroscopy (XPS). Results showed that APANS fabricated from 2% PAN/DMSO solution and amidoximated for 20 min had coarse surface, numerous mesopores, high porosity (88.5%) and large pore volume (20.5 mL/g). The pore formation mechanism revealed that the hierarchical pores were derived from multiscale DMSO crystals shaped by TIPS. Adsorption kinetics results showed that kinetics data were well fitted by pseudo-second-order model (R 2 > 0.99) and the mesopores accelerated the adsorption (equilibrium time of 4 h) due to enormous surface excess and group exposure. Adsorption isotherm could be modeled by Freundlich (R 2 > 0.99) and maximum adsorption capacity was 683.6 mg/g. The adsorption thermodynamics was also investigated, indicating the spontaneous and exothermic adsorption process. APANS exhibited excellent selectivity towards common anions (Cl−, SO 4 2−, NO 3 − and PO 4 3−) and reliable reusability (preserving 80% capacity after five cycles). This adsorbent provided a clean and sustainable strategy for Sb(V) removal from aqueous environment by superhigh capacity, fast rate and reliable reusability. [Display omitted] • Amidoxime-polyacrylonitrile sphere was synthesized via nanoscale TIPS. • The sphere possesses hierarchical pores and abundant amidoxime groups. • The sphere is an efficient adsorbent for antimonate removal from water. • The maximum adsorption capacity was found to be 683.6 mg/g. • Pore formation mechanism was identified using cold scanning electron microscopy. [ABSTRACT FROM AUTHOR]

• Electrostatic spraying was firstly used in COF-LZU1 formation on membrane substrate. • Membrane fouling behavior in DCMD for different ECs was systematically investigated. • COF-based membrane performance in temperature changing DCMD process was studied. Emerging contaminants (ECs) in aqueous ecosystem are becoming a global threat to human beings, which are mainly discharged from industrial wastewater. Direct contact membrane distillation (DCMD) can utilize waste heat to treat industrial wastewater containing ECs, achieving a better balance between removal efficiency and operation cost than other technologies. However, membrane fouling is the major obstacle that impedes DCMD application. Therefore, anti-fouling covalent organic framework COF-LZU1/PVDF composite membranes were prepared via electrostatic spraying and used in DCMD for the first time. Four typical EC compounds (ibuprofen, acesulfame, sulfamethoxazole, and N,N-diethyl-3-methylbenzamide) were selected as targets to investigate the effect of water affinity and charge on membrane fouling. Results showed that COF-1.0 membrane with relatively hydrophilic COF-LZU1 structure exhibited higher permeate flux and salt rejection than commercial PVDF substrate when treating sulfamethoxazole and ibuprofen within pH range of 4–7 and temperature of 40–70 °C. This could be attributed to the weaker hydrophobicity and closer-to-neutral zeta potential of COF-1.0, which weakened the electrostatic and hydrophobic-hydrophobic interactions between membrane and ECs. In addition, the membrane performance comparison in temperature changing DCMD process further showed that COF-1.0 performed better in terms of permeate flux, especially in the gradually decreased temperature condition. Overall, these findings would advance the fundamental understanding and practical application of COF-based membranes in DCMD for ECs treatment. [ABSTRACT FROM AUTHOR]

Nanoparticle doping in membranes is an ideal strategy for improving performance of aqueous-aqueous membrane extraction (AAME). However, its derived adsorption has not been investigated regarding performance enhancement/deterioration of phenol transmembrane mass transfer they might bring, especially in porous membranes. Therefore, supercapacitor-activated carbon (YEC-8)-doped (>30 mg/g) and silica-doped membranes (<0.1 mg/g) only with differentiated adsorption capacity were prepared to identify adsorption impact on phenol extraction from saline-wastewater. Surprisingly, membrane adsorption significantly inhibited phenol transmembrane mass transfer regardless of adsorption saturation rather than enhancement as we hypothesized. Compared to PVDF membrane, extraction performance of silica-doped membrane decreased by 24.0% at 2 g/L phenol. For YEC-8-doped membrane, its extraction performance even decreased by 40%-50% when facing multiple phenol concentrations. These results stated the important role of volatilization-diffusion in phenol transmembrane mass transfer in comparison with solution-diffusion. Membrane characterization and Hagen-Poiseuille model analysis demonstrated that membrane pore complexity would induce partial performance degradation. DFT calculation further confirmed that adsorption of gaseous phenol (−1.7292 eV) within membrane pores was primary limiting step in transmembrane mass transfer. Overall, this study elucidates transmembrane mass transfer pathway, process, and mechanism of phenol in AAME with nanoparticle-doped porous membrane for the first time. [Display omitted] • Impact of doping nano-adsorbent on porous membrane extraction was first studied. • Complexity of membrane pore exacerbated mass transfer resistance of phenol by 24.0%. • Adsorption of gaseous phenol by membrane induced a 44% decrease in mass transfer. • Volatilization-diffusion dominated the mass transfer of phenol in porous membranes. [ABSTRACT FROM AUTHOR]

• A sustainable PAUF process is developed for antimony removal in aqueous solution. • Selection of pH determines antimony rejection (pH = 3) and PEI regeneration (pH = 8). • PES membrane could be reused in cyclic PAUF process after 0.2% NaClO treatment. • PEI with stable antimony rejection performance was regenerated during reverse PAUF. To minimize the health risks from antimony in aqueous environment, a polymer assisted ultrafiltration (PAUF) process with polyethersulfone (PES) membrane was employed to remove antimony for the first time. Effects of polymer, pH value and functional groups/Sb ions quantity ratio on antimony removal were systematically explored. Finally, antimony rejection efficiencies of 85.8 ± 0.9%–94.7 ± 1.9% were obtained with gradually reduced normalized water permeate flux from 1 to 0.61 ± 0.02 in 120 min PAUF process under the optimal conditions of polyethyleneimine (PEI), pH = 3 and functional groups/Sb ions quantity ratio = 8. Relevant mechanism investigations indicated that the macromolecule PEI-Sb complexes were formed mainly due to electrostatic interaction during complexation, and then were rejected in ultrafiltration by pore sieving. Meanwhile, ionic strength experiments indicated that the addition of NaCl resulted in significant decline (4.0 ± 0.8%–49.2 ± 3.2%) in antimony rejection efficiencies due to electric double-layer compressing and competition complexation. Moreover, membrane cleaning of 0.2% NaClO and PEI regeneration under pH value of 8 were performed to achieve sustainable cyclic PAUF with reused membrane and polymer. Simultaneously, antimony also could be recovered for reuse during the regeneration of PEI. Results of steady antimony rejection and water permeation demonstrated that this process is a viable alternative for sustainable antimony removal from aqueous environment. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is an emerging water treatment technology suitable for hypersaline wastewater. However, membrane wetting is a primary obstacle to restrict its widespread industrial use. In this study, a superhydrophobic nanofibrous membrane (labeled as FZP) with high water contact angle of 162.3° and sliding angle of 9.8° was fabricated through fluorinating of zinc oxide (ZnO) blended electrospun polyvinylidene fluoride (PVDF) membrane. In comparison with neat and ZnO blended PVDF (ZP) nanofibrous membranes, FZP membrane has much better anti-wetting property due to its superhydrophobicity and higher liquid entry pressure (LEP) value when desalinating both pure NaCl solution and NaCl solutions with low-surface-tension sodium dodecyl sulfate (SDS) and sparingly soluble salt CaSO 4. LEP values of membranes for SDS and CaSO 4 contained feed solutions were calculated to be smaller than that for pure NaCl solution, accelerating the occurrence of membrane wetting. Temperature gradient across the membrane and Gibbs free energies of CaSO 4 heterogeneous nucleation were further calculated to elucidate the wetting mechanism. Our results provide valuable insights for better developing superhydrophobic membrane and understanding its anti-wetting property in MD process. Image 1 • Superhydrophobic FZP membrane was facilely obtained by ZnO blending and fluorination. • The highest LEP and lowest transmembrane ΔT led to best anti-wetting performance. • The highest ΔG heterogeneous of CaSO 4 is least prone to membrane hydrophilization. [ABSTRACT FROM AUTHOR]

• Porous UAPAN was firstly synthesized and used for Sb (III) and Sb(V) adsorption. • The adsorption conditions (pH, temperature and coexisting anions) were studied. • High adsorption capacities were observed. • Zeta potential, XPS and DFT were adopted to explore adsorption mechanism. Porous modified polyacrylonitrile (PAN) with an ultrahigh percentage of amidoxime groups (UAPAN) was synthesized for the first time and used to adsorb antimonite (Sb(III)) and antimonate (Sb(V)) from aqueous solution. Fourier transform infrared (FT-IR), Zeta potential, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) were adopted to characterize UAPAN and explore adsorption mechanism. Moreover, batch experiments were performed to investigate the influence of various adsorption parameters, including initial pH, contact time, temperature, coexisting ions and reusability on adsorption capacities. Results showed that the maximum adsorption capacities for Sb(III) and Sb(V) were 125.4 and 177.3 mg g−1, respectively, which were much higher than those of other adsorbents reported in literature. The adsorption thermodynamics was evaluated, indicating the spontaneous and endothermic adsorption. The adsorption isotherm was suitable to be modeled by Langmuir isotherm (R2 > 0.96). Results of FT-IR, Zeta potential and XPS indicated that adsorption was involved with electric charge attraction and ligand exchange. DFT further explained that better adsorption of Sb(V) on UAPAN than that of Sb(III) was caused by the higher adsorption energy, more favorable bond lengths and atom charge density. Accordingly, UAPAN is expected to be a compelling candidate for antimony decontamination from aqueous environment. [ABSTRACT FROM AUTHOR]

• External EMBR was set up with superhydrophobic/organophilic electrospun membrane. • External EMBR achieved the salt rejection, phenol permeation and biodegradation. • Phenol and ammonium were simultaneously removed in external EMBR for detoxication. • Microbial community, gene enumeration and EPS release varied with phenol conc. Phenol-laden saline wastewaters can adversely affect water, groundwater, soil, organisms and ecosystems. Given that frequently-used biodegradation process is generally inhibited by salinity, this work aims to solve the problem through a novel configuration of external extractive membrane bioreactor (EMBR) for the objective of simultaneous phenol permeation, salt rejection and biodegradation. Contact angles of 160.9 ± 2.2° (water) and 0.0° (phenol) were observed on the electrospun polydimethylsiloxane/polymethyl methacrylate (PDMS/PMMA) membrane, suggesting this superhydrophobic/superorganophilic membrane was suitable for separating phenol from water-soluble salt. Phenol ranging from 14.1 ± 2.7 to 290.7 ± 10.4 mg/L (stages 1 to 8) was continuously permeated and completely biodegraded in external EMBR under a hydraulic retention time (HRT) of 24 h, which corresponded with detoxification performance improving from 6.3% to 70.5%. After phenol exposure of 8 stages, Proteobacteria and Saccharibacteria became the main phyla for microorganisms. Enumeration of functional genes (phe , amoA , narG , nirS) confirmed that phenol was mainly consumed by denitrifiers and other heterotrophs as the sole carbon and energy source via oxidation and ring cleavage. As bacterial responses, these genes' proliferation was promoted under low phenol concentrations but inhibited under high phenol concentrations. Meanwhile, results of extracellular polymeric substances revealed that protein was the key substance in toxicity resistance, phenol adsorption and transfer. [ABSTRACT FROM AUTHOR]

• Triple layer hydrophobic-hydrophilic composite membrane was firstly fabricated. • The driving force of the composite membrane was theoretically calculated. • Hydrophilic layer could increase the driving force of water vapor across membrane. Electrospinning is a notable technique to prepare nanofibrous membranes with remarkable features required for membrane distillation (MD). However, hydrophobic membrane fabricated by electrospinning alone could hardly ensure a high flux. In this study, triple layer membrane that is composed of a PVDF-PTFE hydrophobic layer, a PET support layer, and a chitosan-polyethylene oxide (CS-PEO) hydrophilic layer, was fabricated by electrospinning. Firstly, the PVDF-PTFE and CS-PEO layers were optimized, whose contact angles and thicknesses were 144.3°, 55 μm and 20°, 75 μm, respectively. Then, the triple layer membrane (TL-M), dual layer membrane without hydrophilic layer (DL-M) were fabricated and tested in a DCMD process using 3.5 wt% NaCl as the feed to illustrate the effect of hydrophilic layer. The triple layer composite membrane (average flux: 19 kg/m−2 h−1, rejection rate: 99.92%) showed better performance in comparison to the dual-layer membrane (average flux: 15 kg/m−2 h−1, rejection rate: 99.88%). In addition, the driving forces of TL-M (from 14.34 to 14.16 kPa) and DL-M (from 13.26 to 12.88 kPa) were calculated. Results suggested the incorporation of hydrophilic layer could increase the driving force, and largely enhance the membrane flux which could ensure the triple layer membrane possesses a good potential for DCMD application. [ABSTRACT FROM AUTHOR]

This study introduced a facile approach for high-performance electrospinning-phase inversion composite membrane, aiming at solving the low mechanical property, low mass transfer and salt leakage in extractive membrane bioreactor (EMBR) for phenol saline wastewater treatment. Composite membrane was fabricated through coating polydimethylsiloxane (PDMS) on electrospun PDMS membrane via dry phase inversion. Its surface was similar to that of phase inversion membrane while the cross section was uniformly distributed electrospun fibers in phase inversion layer, forming interconnected pore. The loose porous structure and high porosity were suitable for phenol permeation, and hydrophobic surface could reject the salt invasion. The tensile strength and elongation at break of composite membrane (56.5 μm thickness) were 1.7 MPa and 60.0%, making it stably operated in EMBR. Effects of different process variables were investigated, including membrane thickness, phenol concentration and wastewater flow rate. Remarkable performance of phenol biodegradation and salt rejection was achieved during EMBR operation, where the maximal phenol removal rate and conductivity variation in microorganism side were 508.9 mg L−1 d−1 and <0.1 ms cm−1, respectively. The highest phenol mass transfer coefficient of 8.8 × 10−7 m s−1 was achieved. It is reasonable to believe that this study fabricate a promising alternative membrane for EMBR application. • High-performance composite PDMS membrane was specially designed for EMBR. • Phase inversion PDMS layer improved the mechanical property of composite membrane. • Internal electrospun PDMS/PMMA fiber decreased the phenol mass transfer resistance. • Remarkable performance of phenol removal and salt rejection was achieved in EMBR. [ABSTRACT FROM AUTHOR]

• Novel E-CDI with catalytic electrodes was developed for phosphonate degradation. • C-MCE with outstanding ORR performance improved the self-generation of H 2 O 2. • A-MCE provided an ideal platform for the reaction between ·OH and phosphonate. • E-CDI exhibited higher degradation efficiency and lower cost than traditional AOPs. Phosphonate is becoming a global interest and concern owing to its environment risk and potential value. Degradation of phosphonate into phosphate followed by the recovery is regarded as a promising strategy to control phosphonate pollution, relieve phosphorus crisis, and promote phosphorus cycle. Given these objectives, an anion-membrane-coated-electrode (A-MCE) doped with Fe-Co based carbon catalyst and cation-membrane-coated-electrode (C-MCE) doped with carbon-based catalyst were prepared as catalytic electrodes, and a novel electrocatalytic capacitive deionization (E-CDI) was developed. During charging process, phosphonate was enriched around A-MCE surface based on electrostatic attraction, ligand exchange, and hydrogen bond. Meanwhile, Fe2+ and Co2+ were self-oxidized into Fe3+ and Co3+, forming a complex with enriched phosphonate and enabling an intramolecular electron transfer process for phosphonate degradation. Additionally, benefiting from the stable dissolved oxygen and high oxygen reduction reaction activity of C-MCE, hydrogen peroxide accumulated in E-CDI (158 μM) and thus hydroxyl radicals (·OH) were generated by activation. E-CDI provided an ideal platform for the effective reaction between ·OH and phosphonate, avoiding the loss of ·OH and triggering selective degradation of most phosphonate. After charging for 70 min, approximately 89.9% of phosphonate was degraded into phosphate, and phosphate was subsequently adsorbed by A-MCE. Results also showed that phosphonate degradation was highly dependent on solution pH and voltage, and was insignificantly affected by electrolyte concentration. Compared to traditional advanced oxidation processes, E-CDI exhibited a higher degradation efficiency, lower cost, and less sensitive to co-existed ions in treating simulated wastewaters. Self-enhanced and selective degradation of phosphonate, and in-situ phosphate adsorption were simultaneously achieved for the first time by a E-CDI system, showing high promise in treating organic-containing saline wastewaters. [Display omitted] [ABSTRACT FROM AUTHOR]

Forward osmosis (FO) membrane fouling is a big obstacle in real textile wastewater treatment. Herein, a series of pretreatments include coagulation (C), microbubbles (Mbs) and their combination process (Mbs + C) were used to alleviate membrane fouling. Their different effects on flux and rejection rate of FO membrane were also investigated. Satisfactory removal efficiencies for UV 254 , dissolved organic carbon (DOC), chemical oxygen demand (COD) and antimony (Sb) of 48.27, 47.80, 40.70 and 41.87% were obtained at the optimum polyaluminum chloride (PAC) dosage of 300 mg L−1 and combined treatment time of 15 min. Compared with C alone, combined Mbs + C resulted in smaller flux decrease (~40%) and higher rejection rate (>98%) of FO membrane. This result confirmed the positive effect of Mbs on the combined processes. Fluorescence excitation-emission matrices coupled with parallel factor (EEM-PARAFAC), gel permeation chromatography (GPC) and gas chromatography mass spectrometry (GC–MS) measurements were further carried out to investigate the mitigation effect of pretreatments on membrane fouling. Results exhibited Mbs + C can significantly remove tryptophan-like substance and aliphatic alcohols due to enhanced coagulation-floatation property and oxidation of hydroxyl radicals. This study provides useful insights for fouling mitigation through Mbs and coagulation in actual FO process when dealing with textile wastewater. [Display omitted] • Microbubble was firstly used to mitigate FO membrane fouling in actual application. • Recovery rate of water after Mbs and coagulation pretreating can reach 75%. • Coagulation and floatation played important roles in alleviating membrane fouling. • Mbs can effectively remove organics with high MW by EEM-PARAFAC and GPC analysis. [ABSTRACT FROM AUTHOR]

• A membrane contactor-like bioreactor was established for phenol-ammonium wastewater. • Phenol-ammonium transmembrane mass transfer was greatly related to pH and temperature. • Established transmembrane mass transfer model fitted well with phenol-ammonium experimental data. • Phenol and ammonium with adjusted concentration were efficiently removed in biodegradation. The development of coal chemical industry usually generates high-concentrated wastewater containing phenol and ammonium, which requires deep treatment before disposal. Herein, a novel combined process of membrane contactor and bioreactor (MCBR) was established for the efficient treatment of phenol-ammonium wastewater for the first time. When pH was in the range of 8–13, the increase of pH weakened the transmembrane mass transfer of phenol and enhanced the mass transfer of ammonia, owing to their different existing forms at different pH values. At a temperature of 20–30 ℃, the transmembrane mass transfer of phenol and ammonia both increased with temperature increasing. Meanwhile, the established transmembrane mass transfer model reflected the same tendencies of phenol and ammonium recovery rates between experiment and theory. The precise control of concentrations of phenol and ammonium by membrane contactor ensured the safety and effectiveness of subsequent biodegradation process. After biodegradation, the concentrations of phenol and ammonium reduced from 120.1 and 78.9 mg/L to 7.8 and 2.5 mg/L, respectively. The volatile solid content of activated sludge remained relatively constant, while the settling ratio decreased from 39 % to 29 %. Overall, this study established a novel MCBR system for green and cost-effective treatment of high-concentrated coal chemistry wastewater. [ABSTRACT FROM AUTHOR]

Janus charged nanofiltration (NF) membranes are appealing for efficient separation of both positively and negatively charged ions/molecules. Nevertheless, polyamide-based Janus charged membranes still face bottlenecks in engineering applications due to their poor fouling and chlorine resistance. To overcome this limitation, herein, bilayer heterostructured Janus charged NF membranes with a negatively charged non-polyamide outer selection layer and a positively charged polyamide inner selection layer were prepared via electrospray polymerization-based strategy for the first time. The evolutionary behavior of the mutually charge neutralization effect between two charged selection layers was explored. Results showed the membrane inner selection layer with denser cross-linked structures and lower positive charge densities exhibited a weak charge neutralization effect, leading to ∼90% rejection for both Na 2 SO 4 and MgCl 2 and >95% rejection for charged dyes. Impressively, the flux recovery rate of Janus NF membrane could reach 91.9% after three bovine serum albumin fouling cycles. More importantly, the non-polyamide outer selection layer could serve as an "armor" to safeguard polyamide inner selection layer, allowing Janus NF membranes to maintain a normalized salt rejection of 0.94 even under 12000 mg L−1 h chlorination conditions. Thus, this work provides an easy strategy for developing Janus NF membranes with high antifouling properties and chlorine resistance. [Display omitted] • Heterostructured Janus NF membranes were developed by coupling electrospray strategy. • The evolving behavior of charge neutralization between charged layers was explored. • Flux recovery ratio of Janus NF membranes reached 91.9% after 3 BSA fouling cycles. • Normalized rejection of Janus NF membranes maintained 0.94 at 12000 ppm h chlorination. [ABSTRACT FROM AUTHOR]

Capacitive deionization (CDI) holds great promise for phosphorus adsorption and recovery from wastewater, while current electrodes exhibit poor salt adsorption capacity (SAC) and selectivity due to co-ion effect and interference of co-existed ions with high concentration. Herein, to overcome these issues, a facile route was proposed to prepare a covalent organic framework-membrane coating electrode (COF-MCE) by depositing polyvinyl alcohol/polyethyleneimine membrane onto activated carbon fiber (ACF) followed by the in-situ growth of COF-LZU1. Compared to ACF and MCE, COF-MCE, with abundant functional groups and specific sites, facilitated electrical double layer (EDL)-based adsorption and induced hydrogen-bond interaction with phosphorus, contributing to a higher SAC of phosphorus (10.5 mg/g) in treating 1 mM NaH 2 PO 4. When treating different mixtures of NaH 2 PO 4 /NaCl, NaH 2 PO 4 /NaNO 3 , and NaH 2 PO 4 /Na 2 SO 4 with molar ratio of 1:5, COF-MCE exhibited the high phosphorus selectivity of 3.62, 5.98 and 7.01, respectively, which was attributed to the synergistic effects of EDL-based adsorption, hydrogen-bond and pseudocapacitance. Desorption experiments revealed that high reversal voltage and alkaline condition can weaken the hydrogen-bond interaction and strengthen the electrostatic repulsion between COF-MCE and phosphorus, thus improving the desorption and recovery of phosphorus. These findings confirmed the high potential of COF-MCE in the effective electrosorption and recovery of phosphorus from wastewater. • COF-MCE was prepared by casting followed by in-situ growth of COF powders. • Inhibited co-ion effect and enhanced EDL formation led to superb P adsorption. • Hydrogen-bond and redox-reaction interaction contributed to high selectivity for P. • A reversal voltage and high pH weakened the interaction and favored P recovery. [ABSTRACT FROM AUTHOR]

Fluoride (F−) pollution in groundwater is an important environmental issue and capacitive deionization (CDI) holds promise for defluorination at moderate concentrations (e.g., 200 −1000 mg L−1). However, existing electrodes suffer from the overlap of electrical-double-layer (EDL) and severe co-ion effects at low (e.g., <200 mg L−1) and high sodium fluoride (NaF) concentrations (e.g., >1000 mg L−1), respectively, exhibiting poor salt adsorption capacity (SAC). Hence, a three-layer structured electrode, "membrane/carbon nanotube (CNT)/activated carbon (AC)" (CNT-MCE), was prepared through electrospinning CNT onto AC, followed by a polymer membrane coating. Compared to AC and membrane coated electrode, CNT-MCE with mesopore-dominated structure prevented EDL overlap, achieving a higher SAC of 40.8 mg g−1 at 100 mg L−1 NaF. At 1500 mg L−1 NaF, the positively charged CNT-MCE exhibited an improved SAC of 58.8 mg g−1 by inhibiting co-ion effects. Meanwhile, CNT-MCE consistently demonstrated superb SACs at 200 − 800 mg L−1 NaF and maintained excellent stability over a wide concentration gradient by inhibiting severe oxidation. Notably, CNT-MCE successfully decreased the F− concentration in simulated groundwater from 3.4 to 1.1 mg L−1. Overall, our work provides an efficient strategy of electrode design to broaden the applicability of CDI for groundwater defluorination over a wide concentration gradient. [Display omitted] • Three-layer structured membrane coating electrode was prepared for F- removal. • High F- adsorption capacities were obtained over the wide concentration gradient. • Mesopore-dominated structure overcame the overlapping of electrical double layer. • Positively charged polymer membrane inhibited the serious co-ion repulsion effect. [ABSTRACT FROM AUTHOR]

• Patterned PA-based dense Janus membrane with high performance was fabricated by a facile R-IP. • PA/PVDF Janus-2.0 showed anti-fouling/-wetting/-scaling properties without compromising flux. • Size-sieving effect, rather than breakthrough pressure, was probably the critical anti-wetting mechanism. • Superhydrophilic and dense enough surface layer was the key to scaling-resistant Janus membrane. Membrane fouling, wetting and scaling are three prominent challenges that severely hinder the practical applications of membrane distillation (MD). Herein, polyamide/polyvinylidene fluoride (PA/PVDF) Janus membrane comprising a hydrophobic PVDF substrate and a patterned dense PA layer by reverse interfacial polymerization (R-IP) was developed. Direct contact MD experiments demonstrated that PA/PVDF Janus membrane could exhibit simultaneously superior resistance towards surfactant-induced wetting, oil-induced fouling and gypsum-induced scaling without compromising flux. Importantly, the size-sieving effect, rather than the breakthrough pressure of the membrane, was revealed as the critical factor that probably endowed its resistance to wetting. Furthermore, a unique possible anti-scaling mechanism was unveiled. The superhydrophilic patterned dense PA layer with strong salt rejection capability not only prevented scale-precursor ions from intruding the substrate but also resulted in the high surface interfacial energy that inhibited the adhesion and growth of gypsum on the membrane surface, while its relatively low surface -COOH density benefited from R-IP process further ensured the membrane with a low scaling propensity. This study shall provide new insights and novel strategies in designing high-performance MD membranes and enable robust applications of MD facing the challenges of membrane fouling, wetting and scaling. [Display omitted] [ABSTRACT FROM AUTHOR]

A distinct shift of bacterial community driven by organic matter (OM) and powder activated carbon (PAC) was discovered in the simultaneous anammox and denitrification (SAD) process which was operated in an anti-fouling submerged anaerobic membrane bio-reactor. Based on anammox performance, optimal OM dose (50 mg/L) was advised to start up SAD process successfully. The results of qPCR and high throughput sequencing analysis indicated that OM played a key role in microbial community evolutions, impelling denitrifiers to challenge anammox’s dominance. The addition of PAC not only mitigated the membrane fouling, but also stimulated the enrichment of denitrifiers, accounting for the predominant phylum changing from Planctomycetes to Proteobacteria in SAD process. Functional genes forecasts based on KEGG database and COG database showed that the expressions of full denitrification functional genes were highly promoted in R C , which demonstrated the enhanced full denitrification pathway driven by OM and PAC under low COD/N value (0.11). [ABSTRACT FROM AUTHOR]

• A novel chemical self-sufficiency zero liquid discharge system was proposed. • Wastewater and waste gas were recovered as fresh water and ionic resources. • Effects of key NF-BMED-MC parameters on the resource recovery were studied. • The scaling-free environment was achieved by the NF-BMED-MC system. Papermaking industry discharges large quantities of wastewater and waste gas, whose treatment is limited by extra chemicals requirements, insufficient resource recovery and high energy consumption. Herein, a chemical self-sufficiency zero liquid discharge (ZLD) system, which integrates nanofiltration, bipolar membrane electrodialysis and membrane contactor (NF-BMED-MC), is designed for the resource recovery from wastewater and waste gas. The key features of this system include: 1) recovery of NaCl from pretreated papermaking wastewater by NF, 2) HCl/NaOH generation and fresh water recovery by BMED, and 3) CO 2 capture and NaOH/Na 2 CO 3 generation by MC. This integrated system shows great synergy. By precipitating hardness ions in papermaking wastewater and NF concentrate with NaOH/Na 2 CO 3 , the inorganic scaling on NF membrane is mitigated. Moreover, the NF-BMED-MC system with high stability can simultaneously achieve efficient CO 2 removal and sustainable recovery of fresh water and high-purity resources (NaCl, Na 2 SO 4 , NaOH and HCl) from wastewater and waste gas without introducing any extra chemicals. The environmental evaluation indicates the carbon-neutral papermaking wastewater reclamation can be achieved through the application of NF-BMED-MC system. This study establishes the promising of NF-BMED-MC as a sustainable alternative to current membrane methods for ZLD of papermaking industry discharges treatment. [Display omitted] [ABSTRACT FROM AUTHOR]