Multifunctional Membrane Research Articles

Bio-inspired fabrication of adsorptive ultrafiltration membrane for water purification: Simultaneous removal of natural organic matters, lead ion and organic dyes

Conventional ultrafiltration membrane is difficult to achieve the multi-component removal of water contaminants including macromolecules and small ions. Meanwhile, a large number of petrochemical-based polymers as membrane material is raising concerns about environmental risk. In this study, we present a feasible way for the manufacture of multifunctional cellulose-based nanocomposite membranes via bio-fabrication by Acetobacter xylinus for water purification. The harvested bacterial cellulose (BC) pellicle was coated by polydopamine (PDA) as a functional layer and molecular linker to immobilize carboxylated cellulose nanocrystals (C-CNCs) to prepare BC/PDA14h/CNCs membrane (BCM/PDA14h/CNCs). The composited PDA and C-CNCs on the BC nanofibers endowed the membrane with a maximum adsorption capacity of up to 167.80 mg g−1 for Pb2+, and 251.58 mg g−1 for methylene blue (MB). Multiple contaminants (heavy metals, organic dyes, and natural organic matter (NOM)) can also be treated by BCM/PDA14h/CNCs simultaneously during the dynamic filtration process. The removal efficiency of BCM/PDA14h/CNCs against the mixture of metal ions is inversely proportional to the radius of hydrated ions. The selective separation studies on binary dye mixtures showed that the separation efficiency of the membrane is mainly related to the electronegativity of dyes. The BCM/PDA14h/CNCs exhibited preferential adsorption for cationic dyes, with a separation efficiency was up to 98%. Dynamic fouling experiments confirmed that the BCM/PDA14h/CNCs presented excellent antifouling performance and showed a high flux recovery ratio. The multifunctional characteristic, high removal efficiency, excellent reusability and stability as well as environmentally friendly feature of the prepared membrane in the present study provide a sustainable approach for membrane fabrication and promising application in water purification.

Structured electroplating sludge derived membrane for one-step removal of oil, metal ions, and anions from oil/water emulsions

The effective simultaneous treatment of hazardous waste sludge and complex oil/water emulsions in one way is urgently desired but still a challenging issue. Herein, this work for the first time presents a green and efficient strategy to fabricate an electroplating sludge (ES) derived multifunctional self-supporting membrane for the one-step removal of emulsified oils, soluble metal ions, and anions in complex oily wastewater. Due to low cost of ES and sustainability of the solvent selected in fabrication process, the large-scale application of the membrane is easily to promote. The assembled hierarchical nanostructure endowed robust underwater superoleophobicity of the membrane even under various corrosive aqueous environments, as well as excellent ultra-low oil adhesion and anti-oil-fouling performance, without chemical modification. Significantly, the multifunctional membrane possessed desirable simultaneous separation efficiency for five typical oil-in-water emulsions (>99.4%, high oil/water selective wettability), including crude oil-in-water emulsion with high viscosity (>99.6%), Cu2+ (>96.1%, surface complexation and ionic exchange), and Cl- (>92.7%, electrostatic attraction). Therefore, this green, low-cost, and multifunctional membrane not only allows the large-scale resource utilization of hazardous waste sludge, but also effectively solves the problems of complex oily wastewater purification.

Multifunctional electrospun membranes with hydrophilic and hydrophobic gradients property for wound dressing

Achieving sustained and stable release of macromolecular antibacterial agents and unidirectional transport of liquids in targeted environment is still a challenge to be addressed in the management of wounds with large amounts of tissue exudates. In this work, a multilayer electrospun membrane (ethylcellulose-ethylcellulose/gelatin-quercetin/Eudragit L-100/polyethylene glycol, EC-EC/Gel-Q/EL/PEG) was designed with hydrophobic-hydrophilic gradients and drug sustained-release properties controlled by self-pumping effect and prepared using sequential electrospinning technology. The capillary force of different layers in the multilayer membrane could be controlled by precisely tuning the polymer concentrations of the inner and middle layers to extract water directly from hydrophobic inner ethylcellulose (EC) layer to hydrophilic middle ethylcellulose/gelatin (EC/Gel) layer. The droplets could not penetrate the hydrophobic side, but the drug molecules in the outer layer quercetin-loaded Eudragit L-100 (Q/EL/PEG) membrane moved after absorbing a large amount of water. The drug release behavior of multilayer wound dressing mainly followed the Korsmeyer-Peppas model. This multifunctional electrospun membrane could rapidly drive the biofluid outflow, effectively block the invasion of external contaminants and continuously release anti-inflammatory drugs, without any obvious cytotoxicity to mouse fibroblast cells. Hence, the above results indicate the excellent therapeutic potential of the proposed biomaterial as a wound dressing for diabetic patients.

Fabrication of Anatase TiO2/PVDF Composite Membrane for Oil-in-Water Emulsion Separation and Dye Photocatalytic Degradation

At present, the types of pollutants in wastewater are more and more complicated, however, the multifunctional membrane materials are in short supply. To prepare a membrane with both high efficient oil-in-water emulsion separation performance and photocatalytic degradation performance of organic dyes, the bifunctional separation membrane was successfully prepared by electrostatic spinning technology of PVDF/PEMA and in situ deposition of anatase TiO2 nanoparticles containing Ti3+ and oxygen vacancies (Ov). The prepared composite membrane has excellent hydrophilic properties (WCA = 15.65), underwater oleophobic properties (UOCA = 156.69), and photocatalytic performance. These composite membranes have high separation efficiency and outstanding anti-fouling performance, the oil removal efficiency reaches 98.95%, and the flux recovery rate (FRR) reaches 99.19% for soybean oil-in-water emulsion. In addition, the composite membrane has outstanding photocatalytic degradation performance, with 97% and 90.2% degradation of RhB and AG-25 under UV conditions, respectively. Several oil-in-water separation and dye degradation experiments show that the PVDF composite membrane has excellent reuse performance. Based on these results, this study opens new avenues for the preparation of multifunctional reusable membranes for the water treatment field.

Multifunctional polymer electrolyte membrane networks for energy storage via ion-dipole complexation in lithium metal battery

A novel concept of energy storage is presented involving ion-dipole complexation within multifunctional polymer electrolyte membrane (PEM), consisting of polyethylene glycol diacrylate (PEGDA) and succinonitrile (SCN) plasticizer and lithium bis-trifluoromethane sulfonyl imide (LiTFSI) salt. A similar complexation of lithium ions with ether oxygen and amine moieties occurs in the thermally cured poly(ethylene glycol) diglycidyl ether (PEGDGE) - polyether amine (Jeffamine D400, 2-arm) co-network. By virtue of the network functional groups, the ion transport is hindered which may be viewed as temporally holding of the Li ions, reminiscent of ion storage. Although some Li ions may be partially immobilized due to ion-dipole complexation, upon prelithiation via deep discharging the lithium metal/PEM/lithium iron phosphate (LFP) battery assembly to the low potential range of 0.01–0.5 V (i.e., oxidation at the Li metal anode), excess mobile Li ions become available that can travel to the cathode through the Li+ saturated complexation sites at ease, exhibiting high ionic conductivity with energy storage capability within the PEM matrix. Another way of supplying Li ions to PEM is through diffusion driven by ion concentration gradient between the two-layer PEM composite composed of a high salt concentration layer and a no-salt layer. The CV measurement was carried out as a function of aging time on the bilayer composite in the PEM potential range of 0.01 to 2.5 V, which indeed revealed a systematic emergence of redox reaction peaks, thereby validating the energy storing concept of the multifunctional PEM network.

One-pot fabrication of SF-DA@PVDF membrane for dye adsorption and oil-in-water emulsion separation

With industry development, the reuse of water and oil resources has become an urgent problem. At present, the evolution of simple-minded approaches to attain modification on the membrane surface for a more complex circumstance, such as oily wastewater and dyes at the same time, has become a red-hot but challenging topic for research. Membrane separation technology has successfully built up to cope with these issues, such as oil-in-water emulsion separation and dye adsorption owning to its benign mechanical characteristics and low power consumption. Therefore, we report a simple-minded one-step approach for uses in oil-in-water emulsion separation and dye adsorption. In this work, a new multifunctional membrane surface is constructed via the concurrent incorporation of silk fibroin (SF) and dopamine hydrochloride (DA) in co-deposition to reach a large flux for complex wastewater separation. The qualified membrane has super hydrophilic in the air and has brilliant oil adhesion resistance underwater. It works comfortably on oil-in-water emulsions (over 10400 L m−2 h−1 bar−1) or dyes (above 3738.68 mg m−2). More importantly, excellent adsorption efficiency (>99%) and extensive adsorption capability (over 2071.91 mg m−2) were achieved by the oil-in-dye emulsion that stabilized with surfactant. It not only possesses a broad span of use outlooks but also enlightens imports for the evolution of functional coating in the future.

A Novel Multifunctional Photocatalytic Separation Membrane Based on Single‐Component Seaweed‐Like g‐C3N4

AbstractMultifunctional separation membrane is usually realized by multi‐component collaborative construction, which makes the membrane preparation method complicated and uncontrollable. Herein, a novel multifunctional photocatalytic separation membrane is prepared by vacuum self‐assembly of single seaweed‐like g‐C3N4 photocatalyst. The seaweed‐like g‐C3N4 gives membrane certain roughness, large specific surface area, excellent hydrophilicity and abundant transport channels. Through a systematic study, the membrane exhibits excellent separation of five oil‐in‐water emulsions with a maximum flux of 3114.0 ± 113.0 L m−2 h−1 bar−1 for 1, 2‐dichloroethane‐in‐water (Dc/W) emulsion and a maximum efficiency of 97.4 ± 0.1% for chloroform‐in‐water (C/W) emulsion. In addition, the seaweed‐like g‐C3N4 with large specific surface area and narrow bandgap render excellent visible light absorption characteristics and accelerate e−‐h+ pairs transport rate, giving the membrane excellent photocatalytic degradation and antibacterial properties. The membrane shows good degradation for eight different pollutants, among which the degradation effect for rhodamine B (RhB), methylene blue (MB), and crystal violet (CV) were ≈100%. The antibacterial efficiency against E. coli and S. aureus is also close to 100%. After 35 consecutive separations of C/W emulsion and 10 consecutive degradations of RhB, the membrane still maintains excellent separation performance. This long‐lasting multifunctional separation membrane exhibits broad application prospects in complex wastewater purification.

Stretchable, durable and asymmetrically wettable nanofiber composites with unidirectional water transportation capability for temperature sensing

The one-way transportation of liquids plays an important role in smart and wearable electronics. Here, we report an asymmetric nanofibrous membrane (ANM) with unidirectional water transport (UWT) capability by integrating one superhydrophilic MXene/Chitosan/Polyurethane (PU) nanofiber membrane (MCPNM) and one ultrathin hydrophobic PU/Polyvinylpyrrolidone (PVP) layer with a “bead-on-string” structure. The UWT performance shows long-term stability and can be well maintained during the cyclic stretching, abrasion and ultrasonic washing tests. The ANM exhibits negative temperature coefficient and is served as a temperature sensor to monitor the temperature variation of the environment, which can provide efficient alarm signals in a hot or cold condition. When attached on person’s skin, the ANM displays a unique anti-gravity UWT behavior. The stretchable, wearable and multi-functional nanofibrous composite membrane with an asymmetric wettability shows potential applications in flexible and wearable electronics, health monitoring, etc.

1D/2D ZnO nanoneedles/Ti3C2 MXene enrobed PVDF electrospun membrane for effective water purification

To advance the emerging field of wastewater treatment, a novel nanostructure decorated porous electrospun membrane was successfully prepared via a combination of electrospinning, vacuum deposition and hydrothermal techniques. 1D ZnO nanoneedles were uniformly enrobed over Ti3C2 incorporated PVDF electrospun membrane. PVDF/Ti3C2/ZnO membrane displayed superhydrophilicity and stable underwater superoleophobicity with excellent separation performance (∼99%) and reusability. The composite membrane maintained an average flux of about 1585 Lm-2h−1 and 1274 Lm-2h−1 for various types of mixtures and emulsions respectively. The impact of intimate interfacial contact and matched energy level alignment between metallic Ti3C2 MXene and ZnO nanoneedles enhanced the separation and migration of charge carriers. The composite membrane demonstrated an exceptional photocatalytic degradation performance (∼96%) over congo red dye under LED light irradiation which is 2.7 and 7.4 times as that of PVDF/ZnO and PVDF/Ti3C2 membranes respectively. Moreover, the membrane maintained good chemical, thermal and mechanical stability under harsh environments and morphological durability even after many cycles of multi-functional operation; proving it to be an excellent candidate in the domain of water purification. The present study introduces a scalable approach for multi-functional membrane fabrication for water purification.

Enhanced the dielectric and piezoelectric properties of polyacrylonitrile piezoelectric composite fibers filled with ionic liquids

AbstractHere, we demonstrate the design and application of a multifunctional piezoelectric composite nanofiber membrane. In this study, the most widely used electrospinning method, by adding a small amount of 1‐allyl‐3‐butylimidazolium tetrafluoroborate ionic liquids and ferric chloride hexahydrate (FeCl3·6H2O) to regulate the structure and properties of polyacrylonitrile (PAN), the mechanical properties, piezoelectric properties, dielectric properties, and ferroelectric properties of composite nanofibers were improved. The results show that the piezoelectric properties of PAN composite fibers are greatly improved under the action of dual fillers. At 103 Hz, the dielectric constant of the PAN composite fiber is as high as 8.24, which is three times that of the pure PAN fiber. The sensor made from the composite nanofibers exhibits excellent sensitivity and high saturation polarization. At low pressure (<1 kPa), the sensitivity of the composite fiber is as high as 0.51 kPa. When we tap the sensor with our finger, the PAN composite fiber produces high piezoelectric output (5.7 V). The results show that the composite nanofibers have great potential in energy storage devices and flexible piezoelectric sensors, among other fields.

Ultrathin bimodal porous membranes with uniform small pores separated by laminated large pores for efficient water separation

Bimodal pore structure design of separation membranes is a promising way to simultaneously improve permeability and selectivity. However, the thickness limitation of bimodal porous membranes is an obstacle to further improving the separation efficiency. In this study, a novel bimodal porous structure with uniform small pores on the surface and a unique laminated large pore structure in the thickness direction was successfully constructed through biaxial stretching of gel films in ultra-high molecular weight polyethylene membranes. With an increase in the draw ratio to 12 × 12, the uniformly refined small pores increased the rejection rate of the carbon nanoparticle solution (particle size distribution of 60–400 nm) to 99.4%, and the unique laminated large pore structure enabled the permeance to reach 1141.8 L m-2h−1 bar−1. By further increasing the draw ratio to 16 × 16, the membrane thickness decreased to 0.91 μm and the permeance was further increased to 2008.2 L m-2h−1 bar−1 while the selectivity slightly decreased to 98.9%. Furthermore, a bimodal porous membrane with sufficient strength (237 MPa of 16 × 16) was efficient for long-term water separation. This study proposes a new design idea for ultrathin porous membranes, which can be further expanded to prepare various antifouling, self-cleaning, and multifunctional separation membranes.

Brain Capillary‐Inspired Self‐Assembled Covalent Organic Framework Membrane for Sodium–Sulfur Battery Separator

AbstractRoom‐temperature sodium–sulfur (RT/Na–S) batteries are a promising low‐cost energy storage technology. However, the vital role of the separator in the system is often overlooked. Inspired by the maintenance of brain homeostasis by human brain capillaries, this work pioneers a host–guest self‐assembled strategy for covalent organic scaffold membranes, endowing the membrane with multiple functions (sodium ion transport, confinement, and conversion of polysulfides) to maintain the stability of the RT/Na–S battery system. The free‐standing multifunctional covalent organic framework membrane (HB/CNT@COF) maximizes the roles of the host framework and guest molecules. Because of the synergistic effect of hydroxynaphthol blue (HB) and multiwalled carbon nanotubes (CNT), the HB/CNT@COF cell exhibits a capacity of 733.4 mAh g−1 with limited capacity fading after 400 cycles at 4 C. This performance is nearly four times that of commercial glass fiber separators. Additionally, the cell demonstrates excellent performance under electrolyte‐poor conditions.

Multifunctional Heterogeneous Ion-Exchange Membranes for Ion and Microbe Removal in Low-Salinity Water.

Here, multifunctional heterogeneous ion-exchange metal nanocomposite membranes were prepared for surface water desalination and bacterial inactivation under low-pressure (0.05 MPa) filtration conditions. Ultrafiltration (UF) heterogeneous ion exchange membranes (IEMs) were modified with different concentrations of AgNO3 and CuSO4 solutions using the intermatrix synthesis (IMS) technique to produce metal nanocomposite membranes. Scanning electron microscopy (SEM) images revealed that the metal nanoparticles (MNPs) (Ag and Cu) were uniformly distributed on the surface and the interior of the nanocomposite membranes. With increasing metal precursor solution concentration (0.01 to 0.05 mol·L-1), the metal content of Ag and Cu nanocomposite membranes increased from 0.020 to 0.084 mg·cm-2 and from 0.031 to 0.218 m·cm-2 respectively. Results showed that the hydrodynamic diameter diameters of Ag and Cu nanoparticles (NPs) increased from 62.42 to 121.10 nm and from 54.2 to 125.7 nm respectively, as the metal precursor concentration loaded increased. The leaching of metals from metal nanocomposite membranes was measured in a dead-end filtration system, and the highest leaching concentration levels were 8.72 ppb and 5.32 ppb for Ag and Cu, respectively. The salt rejection studies indicated that ionic selectivity was improved with increasing metal content. Bacterial filtration showed higher antibacterial activity for metal nanocomposite membranes, reaching 3.6 log bacterial inactivation.

Improvement in Ammonia, Hydrogen, and Methyl Formate Synthesis Process by Employing Multiobjective Optimization of a Novel Multifunctional Membrane Reactor

This investigation analyzes the simultaneous production of hydrogen and ammonia as carbon-free energy carriers and methyl formate (MF) as a widely used chemical intermediate in a multifunctional membrane reactor (MFMR). The MFMR, based on Le Chatelier’s principle, has the advantage of changing the thermodynamic equilibrium by direct thermal coupling between ammonia synthesis and MF production and shifting the chemical equilibrium with the use of the Pd–Ag membrane. In the innovative configuration, the nitrogen conversion rate has been increased from 38.2 to 41.2% and the methanol conversion from 16.3 to 99.1%. Other benefits of the MFMR include providing the required energy for an endothermic reaction and eliminating a furnace and cooler in methanol dehydrogenation and ammonia synthesis reactors. Furthermore, it has been demonstrated that if the ammonia synthesis reaction is positioned at the center side of the MFMR, the nitrogen and methanol conversion are, respectively, 1.32 and 7.34% higher than when the reaction is located at the outer side of the MFMR. Likewise, the effect of operational process parameters such as inlet flow rates, inlet temperatures, and membrane thickness on the performance of each reaction has been studied. Utilizing multiobjective optimization (MOO), it has been observed that ammonia and MF production yields can reach 20.3 and 24.1%, respectively.

Bidirectional Water‐Stream Behavior on a Multifunctional Membrane for Simultaneous Energy Generation and Water Purification (Adv. Mater. 7/2023)

Renewable Energy Generation In article number 2209076, Ji-Soo Jang, Tae Gwang Yun, and co-workers demonstrate an electricity generation and purification membrane (EPM) model that shows potential applicability for next-generation renewable energy-generation, enabling effective utilization of polluted water resources, laying the foundation for a novel environmentally friendly water-purification and energy-generation system, and overcoming pre-existing functional membrane technology. Further development of the model will contribute to overcoming the world-wide problem of water scarcity and to advancing ecofriendly electricity-generation.

Multifunctional plasmonic Ag–Cu alloy nanoparticles immobilized on reduced graphene oxide for simultaneous solar-driven steam, wastewater purification, and electricity generation

Solar-driven water evaporation is crucial for drinkable water production using cost-effective solar energy and has recently gained more interest through the improvement of heat localization strategies. However, the original water sources may contain oil impurities and other organic pollutants that seriously impair the evaporation process and pose environmental hazards. Here, we developed a multifunctional nanocomposite Ag, Cu-rGO for the production of clean water by simultaneous photocatalysis, oil resistance, adsorption, and water evaporation powered by the sun. The phonon-assisted relaxation process under solar irradiation was effectively accelerated by the incorporation of rGO by Ag and CuNPs alloy, which can alter the bandgap and introduce a significant number of intermediate band (IB) states. We demonstrate that by employing the Ag, Cu-rGO evaporator under solar light irradiation, a high-water evaporation rate of 1.89 kg m−2 h−1 with a high solar-to-heat conversion efficiency of 90.2% can be accomplished. Additionally, the membrane can concurrently purify the raw water during solar evaporation by organic dye degradation, heavy metals adsorption, oil resistance, and pathogenic bacteria disinfection. Meanwhile, the heat dissipation to the bulk water can be recovered by the conversion to electricity using a commercial TE-module which simultaneously generates voltage generation of 17.3 mV with a power density of 5.72 W m−2. For solar-driven water evaporation from multiple sources, such an all-in-one multifunctional membrane is an excellent candidate.

Multifunctional barrier membranes promote bone regeneration by scavenging H2O2, generating O2, eliminating inflammation, and regulating immune response

The injured bone microenvironment is typically characterized by high-level reactive oxygen species (ROS, mainly H2O2) and low content of oxygen. The former can cause cell apoptosis, induce immune imbalance and inflammation, inhibit osteogenic differentiation, and delay bone repair. In this work, barrier membranes made of a combination of hydroxyapatite nanowires (HAp NWs) and polylactic acid (PLA) loaded with manganese dioxide nanosheets (NSs) (HP@Mn) were prepared to guide bone regeneration (GBR). Due to the catalytic function of MnO2, HP@Mn membranes are able to effectively decompose H2O2 to generate O2. In vitro experiments demonstrated HP@Mn membranes inhibited the apoptotic process caused by high level of H2O2, decreased intracellular oxidative stress, suppressed inflammation-related gene/protein expression, and inhibited macrophage M1 polarization. The nanostructured HAp stimulated osteogenic differentiation, and the loading of MnO2 NSs played a synergistic effect. In addition, the barrier function of PLA could hamper the epithelium overgrowth, providing the development space for periodontal regeneration. By scavenging H2O2, generating O2, eliminating inflammation, and regulating immune response, HP@Mn membranes efficiently promoted bone regeneration. Our results confirmed that composite membranes have great potential for application in GBR, and provide a reference for future design of bone repair materials.

STRA6 Promotes Thyroid Carcinoma Progression via Activation of the ILK/AKT/mTOR Axis in Cells and Female Nude Mice.

Metastasis has emerged to be an important cause for poor prognosis of thyroid carcinoma (TC) and its molecular mechanisms are not fully understood. STRA6 is a multifunctional membrane protein widely expressed in embryonic and adult tissues. The function and mechanism of STRA6 in TC remain elusive. We aimed to explore the role of STRA6 in TC progression and provide a therapeutic target for TC. The expression and clinicopathological relevance of STRA6 were explored in TC. Stable STRA6-knockdown TC cells were established and used to determine the biological function of STRA6 in vitro and in vivo. RNA sequencing and co-immunoprecipitation were performed to unveil the molecular mechanism of STRA6 in TC progression. The potential of STRA6 as a therapeutic target was evaluated by lipid nanoparticles (LNPs) containing siRNA. STRA6 was upregulated in TC and correlated with aggressive clinicopathological features, including extrathyroidal extension and lymph node metastasis, which contributed to the poor prognosis of TC. STRA6 facilitated TC progression by enhancing proliferation and metastasis in vitro and in vivo. Mechanistically, STRA6 could interact with integrin-linked kinase (ILK) and subsequently activate the protein kinase B/mechanistic target of rapamycin (AKT/mTOR) signaling pathway. We further unveiled that STRA6 reprogrammed lipid metabolism through SREBP1, which was crucial for the metastasis of TC. Moreover, STRA6 siRNA delivered by LNPs significantly inhibited cell growth in xenograft tumor models. Our study demonstrates the critical roles of STRA6 contributing to TC progression via the ILK/AKT/mTOR axis, which may provide a novel prognostic marker as well as a promising therapeutic target for aggressive TC.

Multifunctional PVDF Membrane Coated with ZnO-Ag Nanocomposites for Wastewater Treatment and Fouling Mitigation: Factorial and Mechanism Analyses

In this study, a multifunctional poly(vinylidene fluoride) (PVDF) membrane was developed through chemical binding with ZnO-Ag nanocomposites to increase wastewater treatment efficiency. The unique characteristics of ZnO-Ag nanocomposites endowed the membrane with high surface hydrophilicity, organic/bio fouling resistance, and photocatalytic antibacterial activity. The significantly decreased water contact angle and increased under-water oil contact angle suggested improved surface hydrophilicity and organic fouling resistance. Through factorial analysis, it was found that the antibacterial activity of the multifunctional membrane could be significantly improved under visible light condition and with ZnO-Ag nanocomposites which obtained under higher Ag concentration and sintering temperature. The increase of Ag composition of ZnO-Ag nanocomposites on modified membrane surface significantly improved the membrane antibacterial activity but had little effect on membrane hydrophilicity. In addition, the photocatalytic antibacterial activity of ZnO-Ag nanocomposites could further improve the membrane biofouling resistance through simple exposure to visible light. The effects of different Ag chemical states on the performances of ZnO-Ag nanocomposites and the corresponding modified membranes were studied, and the relevant mechanism of antibacterial activity under both dark and light conditions was discussed. Filtration experiments with secondary wastewater effluent as feed solution indicated that the developed membrane exhibited one order of magnitude larger permeate flux compared to the pristine PVDF membrane, while maintaining comparable bacteria rejection rates during the filtration process.

A multifunctional composite membrane for high-safety lithium-ion batteries

Thermal runaway and dendrite growth in lithium-ion batteries (LIBs) induce serious safety hazards and impede their further applications.