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Abstract Phosphoric acid doped proton exchange membranes often experience performance degradation above 200 °C due to membrane creeping and phosphoric acid evaporation, migration, dehydration, and condensation. To address these issues, here we present gel-state polybenzimidazole membranes with double cross-linked three-dimensional layered structures via a polyphosphoric acid sol-gel process, enabling stable operation above 200 °C. These membranes, featuring proton-conducting cross-linking phosphate bridges and branched polybenzimidazole networks, effectively anchor and retain phosphoric acid molecules, prevent 96% of its dehydration and condensation, improve creep resistance, and maintain excellent proton conductivity stability. The resulting membrane, with superior through-plane proton conductivity of 0.348 S cm−1, delivers outstanding peak power densities ranging from 1.20–1.48 W cm−2 in fuel cells operated at 200-240 °C and a low voltage decay rate of only 0.27 mV h−1 over a 250-hour period at 220 °C, opening up possibilities for their direct integration with methanol steam reforming systems.

Thin film nano-composite polyamide (TFN PA) total heat exchange membranes (THEMs) containing ZIF-7, ZIF-8, ZIF-9 and ZIF-67 particles (PTs) introduced during interface polymerization process were prepared. A novel integrated online testing system was established to simultaneously evaluate their CO2 and moisture exchange rates as well as energy recovery efficiencies. ZIF PTs added in water phase improved the CO2 barrier property of the THEMs due to their good dispersion in water, the coordination of the excess cations on their surfaces with the –NH2 groups of MPD from the PA matrix and partially by increasing the PA layer thickness. Addition of ZIF PTs in organic phase showed variety of effects on the CO2 barrier property of the THEMs depending on their dispersion, structure rigidity, and interaction with the PA polymer matrix. Adding 0.01 g/144 cm2 of ZIF-67 in aqueous phase and 0.02 g/144 cm2 of ZIF-9 in organic phase could form TFN membranes with improved CO2 barrier property without sacrificing energy recovery efficiencies. ZIF-9 addition in organic phase formed ZIF/PA TFN THEMs with the highest total heat recovery rates of 72% and lowest on-line CO2 exchange rates of 1.7%. The newly obtained online CO2 exchange rates (hCO2) were found to have good correlation with the off-line CO2 permeance values (PERCO2), ηCO2 = ln (PERCO2)%-0.005, with a high Pearson's R value of 0.9914. There was also a linear correlation between the permeation selectivity obtained online (DSH2O/CO2) and calculated offline (ISH2O/CO2), ISH2O/CO2 = 0.289*DSH2O/CO2+14.4, with an excellent Pearson's R values of 0.9942. The integrated testing system could give more realistic evaluation for novel THEMs with a lot less efforts.

Polydopamine (PDA) depositions, inspired by mussel foot adhesive proteins, represent a versatile method for preparing separation membranes. However, PDA-based nanofiltration membranes are limited by the long preparation time and moderate flux. This work modulated PDA deposition processes with a spiro-piperazine (SPIP) molecule containing two secondary amine groups and a quaternary ammonium salt. The SPIP could be covalently inserted into PDA coating structures via Michael addition reaction to accelerate the deposition process of PDA and reduce its aggregation. In addition, the rigid and spiro configuration of SPIP molecules provides higher fractional free volume and leads to looser and more uniform structures in the PDA coating. As such, water permeance of PDA/SPIP membranes is 73 ​L ​m−2 ​h−1 bar−1, 4.6 times improved compared with PDA control membranes, while the dye rejection (>99% for Congo red) is maintained high. These results demonstrate that SPIP is an effective molecule for the structure and performance engineering of mussel-inspired PDA nanofiltration membranes.

Summary: Highly effective decontamination of lead is a primary challenge for ecosystem protection and public health. Herein, we report a methodology of ternary cations intercalation to synthesize Ti3C2Tx MXene by structural control with angstrom-level precision through mixed fluorinated salts wet etching-alkalization approach for high-efficient lead adsorption. The successive introduction of lithium, potassium, and sodium ions continuously weakens interaction forces between Ti3C2Tx layers, resulting in achieving fine tailored interlayer distance from 9.8 to 15.9 Å. A high density of complexing groups are formed after ternary cations intercalation, which greatly improve the hydrophilicity of Ti3C2Tx to enhance the accessibility and shorten the mass transfer and provide abundant adsorption sites to exhibit strong complexing effects with lead ions. The prepared ternary cations-intercalated Ti3C2Tx nanosheets exhibited a high adsorption capacity (267.2 mg/g) toward lead ions and sharply cut down lead concentration from 10 to 0.009 mg/L, far below the drinking water standards (0.015 mg/L).

Thin-film composite (TFC) polyamide membranes have a wide range of applications in forward osmosis, but tuning the water flux remains a significant challenge due to concentration polarization. The generation of nano-sized voids within the polyamide rejection layer can change the roughness of the membrane. In this experiment, the micro-nano structure of the PA rejection layer was adjusted by adding sodium bicarbonate to the aqueous phase to generate nano-bubbles, and the changes of its roughness with the addition of sodium bicarbonate were systematically demonstrated. With the enhanced nano-bubbles, more and more blade-like and band-like features appeared on the PA layer, which could effectively reduce the reverse solute flux of the PA layer and improve the salt rejection of the FO membrane. The increase in roughness raised the area of the membrane surface, which led to a larger area for concentration polarization and reduced the water flux. This experiment demonstrated the variation of roughness and water flux, providing an effective idea for the preparation of high-performance FO membranes.

Membrane materials with excellent selectivity and high permeability are the key for high-efficiency membrane separation. New-type porous materials have developed as ideal building blocks for molecular sieving membranes due to their inherent properties, such as permanent porosity, high surface area, structural diversity and low mass transfer barriers. In actual industrial promotion and separation applications, porous materials need to be combined with substrates to prepare porous composite membranes. In order to reduce costs and increase processing flexibility, the combination of organic polymer substrates and porous materials has received more attentions. The multifunctional design strategy of the membrane material and membrane structure of porous composite membranes based on the organic subatrates is the key to realize the further improvement of mass transfer. In this review, we focus on the organic matrix porous composite membrane based on the participation of inorganic-organic hybrid materials and organic-organic composite materials, and conduct an in-depth discussion on the transport mechanism of porous composite membranes, and highlight diverse structural control strategies from the perspectives of macrostructural design and microstructural regulation of membrane structures. Finally, the applications of porous composite membrane based on organic substrate in precise molecular sieving are summarized, and the future opportunities and challenges in this field are discussed briefly.

Developing novel monomers used for aromatic polyamide membranes is one of the promising modifications to tailor the membranes more efficient. Acyl chloride-based compound as the organic phase reactive monomer is vital to the fabrication of membranes. This study focuses on designing and synthesizing a novel acyl chloride monomer 5-(1-pyrrolidinyl)-1,3-benzenedicarbonyl dichloride (PIPC) based on the purpose of improving membrane permeability and anti-fouling, and preliminarily verify its feasibility for the synthesis of aromatic polyamide membranes. PIPC monomer with a rigid pyrrolidinyl group (–NC4H8) was synthesized from three steps of N-alkylation, ester hydrolysis and acylation reaction successively. IR and 1HNMR spectra were employed to demonstrate the successful synthesis of PIPC. The application of PIPC in the membrane field was also implemented via using PIPC alone as the organic phase reactive monomer, the first/second organic phase reactive monomer, and PIPC and trimesoyl chloride (TMC) together act as the organic phase reactive monomer to react with m-phenylenediamine (MPD) by interfacial polymerization (IP). The MPD-PIPC-TMC membrane prepared by PIPC as the first organic phase reactive monomer exhibited the highest water flux (27.89 ​L ​m−2 ​h−1), with the increase of 36.8% than the MPD-TMC membrane (20.38 ​L ​m−2 ​h−1), while maintaining similar salt rejection. The PIPC with a rigid pyrrolidinyl group was demonstrated to be a promising organic phase monomer for further synthesizing high permeability aromatic polyamide membrane, which showed great application prospects in the field of membrane industry.

Nanofiltration (NF) membranes with a high permeability and rejection are of great interest in desalination, separation and purification. However, how to improve the permeation and separation performance still poses a great challenge in the preparation of NF membranes. Herein, the novel composite NF membrane was prepared through the interfacial polymerization of M-phenylenediamine (MPD) and trimesoyl chloride (TMC) on a double-walled carbon nanotube (DWCNT) interlayer supported by PES substrate. The DWCNT interlayer had a great impact on the polyamide layer formation. With the increase of the DWCNT dosage, the XPS results revealed an increase in the number of carboxyl groups, which decreased the crosslinking degree of the polyamide layer. Additionally, the AFM results showed that the surface roughness and specific surface area increased gradually. The water flux of the prepared membrane increased from 25.4 L/(m2·h) and 26.6 L/(m2·h) to 109 L/(m2·h) and 104.3 L/(m2·h) with 2000 ppm Na2SO4 and NaCl solution, respectively, under 0.5 MPa. Meanwhile, the rejection of Na2SO4 and NaCl decreased from 99.88% and 99.38% to 96.48% and 60.47%. The proposed method provides a novel insight into the rational design of the multifunctional interlayer, which shows great potential in the preparation of high-performance membranes.

Inorganic membranes have been developed rapidly in recent years because of excellent anti-fouling performance, high mechanical strength and outstanding resistances to acid and alkali. However, the high production cost still restricts its large-scale industrial application. In this work, an environmental friendly unidirectional freezing method via introducing camphene as a reusable template was adapted to prepare porous cement membranes (PCMs). The naturally formed and highly aligned porous structures of PCMs could be divided into three parts: a dense layer, a transition layer and a supporting layer. With the solid content rising from 40 wt.% to 60 wt.%, the pore size of the PCMs decreased from 3.34 nm to 3.62 nm, the bovine serum albumin (BSA) rejection increased from 81.3% to 93.5% and water flux decreased from 346.8 L·m−2·h−1 to 167.3 L·m−2·h−1 (0.2 MPa). Significantly, the performance of PCMs was maintained; even the camphene was reused 20 times. Additionally, the recovery rate of camphene could be reached up to 97.16%. Therefore, this method is cost effective and environmental friendly, which endowed the PCMs great potential in water treatment.

Abstract Capacitive deionization (CDI) as a novel energy and cost‐efficient water treatment technology has attracted increasing attention. The recent development of various faradaic electrode materials has greatly enhanced the performance of CDI as compared with traditional carbon electrodes. Prussian blue (PB) has emerged as a promising CDI electrode material due to its open framework for the rapid intercalation/de‐intercalation of sodium ions. However, the desalination efficiency, and durability of previously reported PB‐based materials are still unsatisfactory. Herein, a self‐template strategy is employed to prepare a Poly(3,4‐ethylenedioxythiophene) (PEDOT) reinforced cobalt hexacyanoferrate nanoflakes anchored on carbon cloth (denoted as CoHCF@PEDOT). With the high conductivity and structural stability achieved by coupling with a thin PEDOT layer, the as‐prepared CoHCF@PEDOT electrode exhibits a high capacity of 126.7 mAh g−1 at 125 mA g−1. The fabricated hybrid CDI cell delivers a high desalination capacity of 146.2 mg g−1 at 100 mA g−1, and good cycling stability. This strategy provides an efficient method for the design of high‐performance faradaic electrode materials in CDI applications.

Summary: Graphene oxide (GO) nanosheets with unique structure have received much attention in providing opportunity for high-performance membranes in separation. However, the rational design of ultrathin graphene membranes with controlled structures remains a big challenge. Here, we report a methodology to synthesize dual metal-coordinated ultrathin nanoporous graphene nanofilms by tailoring well-aligned nanocrystals as building blocks on heteroatom-doped GO nanosheets with tunable architectures. Manipulation of metal nitrate as bifunctional dopants realizes N-doping of graphene oxide and preferential growth of α-Mn2O3 nanocrystals. Generation of Mn-O-C bond during cross-linking greatly strengthens the stability of membranes for long-term steady operation. Meanwhile, because of spatial confinement effects and high binding energy, N-doped reduced GO nanosheets are desirable supports to construct numerous Mn-N-C bonds, thus generating artificial nanopores to significantly increase nanochannels for ultrafast mass transport. Moreover, the size-selective permeability of ultrathin nanoporous GO-based nanofilms can be optimized by managing the types of metal source for target coordination.

Recently, the fine-grained geolocalization of User-Generated Short Texts (UGST) has become increasingly important. One challenge is that UGST contains relatively little location-indicative information due to such limitations as text length. Therefore, extract and effectively use the location-indicative information is the key issue for improving the effect of geolocalization. The existing works only consider the global weight of the terms and do not distinguish between the importance of identical terms in different locations. In addition, the existing add-one smoothing masks the difference between the features of different locations. In this paper, we propose a fine-grained geolocalization method to predict the PoI-level location of UGSTs based on a weight probability model (FGST-WP). The method mainly includes three parts: 1) Using the reverse maximum match algorithm to filter out UGSTs that do not contain any location-indicative information. 2) Building coupling of terms and locations and adopting a mixed weight strategy to assign weights to terms. 3) Calculating the probability of nongeotagged UGST posted from each location and selecting k locations according to the top-k probabilities. The accuracy of FGST-WP on the three ground-truth datasets reaches 45%, 68%, and 72%, respectively. The results indicate the superior performance of FGST-WP.

A commercial interest in the improvement in the separation performance and permeability of porous materials is driving efforts to deeply explore new preparation methods. In this study, the porous silicate cement membranes (PSCMs) were successfully prepared through an adjustable combination of hot–dry casting and a cement hydration process. The obtained membrane channel was unidirectional, and the surface layer was dense. The physical characteristics of the PSCMs including their pore morphology, porosity, and compressive strength, were diversified by adjusting the solid content and hot–dry temperature. The results indicated that with the solid content increasing from 40 wt. % to 60 wt. %, the porosity decreased by 8.07%, while the compressive strength improved by 12.46%. As the hot–dry temperature increased from 40 °C to 100 °C, the porosity improved by 23.04% and the BET specific surface area and total pore volume enlarged significantly, while the compressive strength decreased by 27.03%. The pore size distribution of the PSCMs exhibited a layered structure of macropores and mesopores, and the pore size increased with the hot–dry temperature. Overall, the PSCMs, which had typical structures and adjustable physical characteristics, exhibited excellent permeability and separation performance.

The realistic resistance zone of water and salt molecules to transport across a TFC-RO membrane is the topmost polyamide nanofilm. The existence of hollow voids in the fully aromatic polyamide (PA) film gives its surface ridge-and-valley morphologies, which confuses the comprehensions of the definition of the PA thickness. The hollow voids, however, neither participate in salt–water separation nor hinder water penetrating. In this paper, the influence of intrinsic thickness (single wall thickness) of the PA layer on water permeability was studied by adjusting the concentration of reacting monomers. It confirms that the true permeation resistance of water molecules originates from the intrinsic thickness portion of the membrane. The experimental results show that the water permeability constant decreases from 3.15 ± 0.02 to 2.74 ± 0.10 L·m−2·h−1·bar−1 when the intrinsic thickness of the membrane increases by 9 nm. The defects on the film surface generate when the higher concentration of MPD is matched with the relatively low concentration of TMC. In addition, the role of MPD and TMC in the micro-structure of the PA membrane was discussed, which may provide a new way for the preparation of high permeability and high selectivity composite reverse osmosis membranes.

Nanofiltration (NF) is a separation technology with broad application prospects. Membrane fouling is an important bottleneck-restricting technology development. In the past, we prepared a positively charged polyethyleneimine/trimesic acid (PEI/TMA) NF membrane with excellent performance. Inevitably, it also faces poor resistance to protein contamination. Improving the antifouling ability of the PEI/TMA membrane can be achieved by considering the hydrophilicity and chargeability of the membrane surface. In this work, sodium chloroacetate (ClCH2COONa) is used as a modifier and is grafted onto the membrane surface. Additionally, 0.5% ClCH2COONa and 10 h modification time are the best conditions. Compared with the original membrane (M0, 17.2 L m−2 h−1), the initial flux of the modified membrane (M0-e, 30 L m−2 h−1) was effectively increased. After filtering the bovine albumin (BSA) solution, the original membrane flux dropped by 47% and the modified membrane dropped by 6.2%. The modification greatly improved the antipollution performance of the PEI/TMA membrane.

In this paper, we used an octadecylamine functionalized graphene oxide (ODA@GO) to induce the confined growth of a polyamide nanofilm in the organic and aqueous phase during interfacial polymerization (IP). The ODA@GO, fully dispersed in the organic phase, was applied as a physical barrier to confine the amine diffusion and therefore limiting the IP reaction close to the interface. The morphology and crosslinking degree of the PA nanofilm could be controlled by doping different amounts of ODA@GO (therefore adjusting the diffusion resistance). At standard seawater desalination conditions (32,000 ppm NaCl, ~55 bar), the flux of the resultant thin film nanocomposite (TFN) membrane reached 59.6 L m−2 h−1, which was approximately 17% more than the virgin TFC membrane. Meanwhile, the optimal salt rejection at seawater conditions (i.e., 32,000 ppm NaCl) achieved 99.6%. Concurrently, the boron rejection rate was also elevated by 13.3% compared with the TFC membrane without confined growth.

Carbon-based materials have attracted intensive attentions for a wide range of energy and environment-related applications. Energy storage/conversion devices with improved performance have been achieved by utilization of metal-organic-framework (MOF)-derived carbon structures as active materials in recent years. However, the effects of MOF precursors on the performance of derived carbon materials are rarely investigated. Here, we report that the incorporation of small amount of Fe or Ni in Co-based MOFs leads to a significant enhancement for the derived carbon nanotube-based frameworks (CNTFs) in Na+/Cl− ion electrosorption. Further investigation revealed the enhanced performance can be attributed to the improved specific surface area, electrical conductivity, and electrochemical activity. Notably, the CoFe-CNTF derived from bimetallic CoFe-MOFs achieves a high ion adsorption capacity of 37.0 mg g−1, superior to most of recently reported carbon-based materials. Furthermore, the CoFe-CNTF also demonstrates high catalytic activity toward oxygen evolution reaction (OER) with a Tafel slope of 87.7 mV dec−1. After combination with three-dimensional graphene foam (3DG), the resultant CoFe-CNTF-coated 3DG is used as air-cathode to fabricate a flexible all-solid-state Zn-air battery, which exhibits a high open circuit potential of 1.455 V. Importantly, the fabricated flexible battery can light a light-emitting diode (LED) even when it is bent. This work provides new insights into designs of high-performance and flexible electrode based on MOF-derived materials.

Developing monovalent cation permselective membranes (MCPMs) with high-efficient permselectivity is the core concern in specific industrial applications. In this work, we have fabricated a series of novel cation exchange membranes (CEMs) based on sulfonated polysulfone (SPSF) surface modification by polyethyleneimine (PEI) and 4′-aminobenzo-12-crown-4 (12C4) codeposited with dopamine (DA) successively, which was followed by the cross-linking of glutaraldehyde (GA). The as-prepared membranes before and after modification were systematically characterized with regard to their structures as well as their physicochemical and electrochemical properties. Particularly, the codeposition sequence of modified ingredients was investigated on galvanostatic permselectivity to cations. The modified membrane (M-12C4-0.50-PEI) exhibits significantly prominent selectivity to Li+ ions (PMg2+Li+ = 5.23) and K+ ions (PMg2+K+ = 13.56) in Li+/Mg2+ and K+/Mg2+ systems in electrodialysis (ED), which is far superior to the pristine membrane (M-0, PMg2+Li+ = 0.46, PMg2+K+ = 1.23) at a constant current density of 5.0 mA·cm−2. It possibly arises from the synergistic effects of electrostatic repulsion (positively charged PEI), pore-size sieving (distribution of modified ingredients), and specific interaction effect (12C4 ~Li+). This facile strategy may provide new insights into developing selective CEMs in the separation of specific cations by ED.

The work briefly introduces the nano-composite reverse osmosis (RO) membrane with more permeability and selective performance, and we adopted the phenyltrichlorosilane precursor with better chemical stability and greater spatial resistance. The phenyltrichlorosilane concentration was mainly discussed in this work. The in-situ hydrolysis of phenyltrichlorosilane and the occurrence of ammonia hydrolysis make it effectively incorporated into the polyamide film. The covalent bond and hydrogen bond of phenyltrichlorosilane and polyamide (PA) can be realized. The phenyl group can extend in the polyamide polymer network and give the film corresponding functions. There will be fewer non-selective defects between phenyltrichlorosilane and PA. Under the premise of maintaining the water-salt selectivity of the membrane, along with the increase of benzene trichlorosilane loading, the 300% pure water flux can be achieved and the desalination rate remains at 98.1–98.9%. This reverse osmosis (RO) is suitable for household water purification.

The advantages of thin film nanocomposite reverse osmosis (TFN-RO) membranes have been demonstrated by numerous studies within the last decade. This study proposes a facile and novel method to tune the microscale and nanoscale structures, which has good potential to fabricate high-performance TFN-RO membranes. This method involves the addition of alkyl capped silica nanoparticles (alkyl-silica NPs) into the organic phase during interfacial polymerization (IP). We discovered for the first time that the high concentration alkyl-silica NPs in organic solvent isopar-G can limit the diffusion of MPD molecules at the interface, therefore shaping the intrinsic thickness and microstructures of the PA layer. Moreover, the alkyl group modification greatly reduces the NPs agglomeration and increases the compatibility between the NPs and the PA matrix. We further demonstrate that the doping of alkyl-silica NPs impacts the performance of the TFN-RO membrane by affecting intrinsic thickness, higher surface area, hydrophobic plugging effect, and higher surface charge by a series of characterization. At brackish water desalination conditions (2000 ppm NaCl, 1.55 MPa), the optimal brackish water flux was 55.3 L/m2∙h, and the rejection was maintained at 99.6%, or even exceeded this baseline. At seawater desalination conditions (32,000 ppm NaCl, 5.5 MPa), the optimized seawater flux reached 67.7 L/m2∙h, and the rejection was sustained at 99.4%. Moreover, the boron rejection was elevated by 11%, which benefits from a hydrophobic plugging effect of the alkyl groups.

This study reported a series of thin film composite (TFC) membranes with single-walled nanotubes (SWCNTs) interlayers for the forward osmosis (FO) application. Pure SWCNTs with ultrahigh length-to-diameter ratio and without any functional group were applied to form an interconnect network interlayer via strong π-π interactions. Compared to the TFC membrane without SWCNTs interlayer, our TFC membrane with optimal SWCNTs interlayer exhibited more than three times the water permeability (A) of 3.3 L m−2h−1bar−1 in RO mode with 500 mg L−1 NaCl as feed solution and nearly three-fold higher FO water flux of 62.8 L m−2 h−1 in FO mode with the deionized water as feed solution and 1 M NaCl as draw solution. Meanwhile, the TFC membrane with SWCNTs interlayer exhibited significantly reduced membrane structure parameters (S) to immensely mitigate the effect of internal concentration polarization (ICP) in support layer with micro-sized pores in favor of higher water flux. It showed that the pure SWCNTs interlayer could be an effective strategy to apply in FO membranes.

A facile membrane surface modification process for improving permselectivity and antimicrobial property was proposed. A polydopamine (PDA) coating was firstly fabricated on pristine anion exchange membrane (AEM), followed by in situ reduction of Ag without adding any extra reductant. Finally, 2,5-diaminobenzene sulfonic acid (DSA) was grafted onto PDA layer via Michael addition reaction. The as-prepared AEM exhibited improved permselectivity (from 0.60 to 1.43) and effective inhibition of bacterial growth. In addition, the result of the long-term (90-h continuous electrodialysis) test expressed the excellent durability of the modified layer on membrane surface, because the concentration of Cl− and SO42− in diluted chamber fluctuated ~0.024 and 0.030 mol·L-1 with no distinct decline. The method described in this work makes the full use of multifunctional PDA layer (polymer-like coating, in situ reduction and post-organic reaction), and a rational design of functional AEM was established for better practical application.

A ternary nanocomposite consisting of N-doped graphene (NGR)/TiO2/activated carbon (NGRT@AC) was prepared, and the components’ synergetic effect on dye degradation was investigated after deposition on the surface of a polysulfone membrane (PSF). As far as we know, this ternary composite catalyst has never previously been used to degrade dyes nor been used as a functional layer for separation membranes. The surface morphology and structure of the as-prepared membranes were analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The NGRT@AC-modified PSF membrane (NGRT@AC-PSF) presents excellent photodegradation efficiency to methyl orange (MO) under both UV (95.2%) and sunlight (78.1%) irradiation, much higher than those values of PSF, TiO2- modified PSF (TiO2-PSF), and N-doped graphene/TiO2 (NGRT)-modified PSF membranes (NGRT-PSF) under the same conditions. The high flux recovery ratio (95.5%) demonstrates that the NGRT@AC-PSF membrane shows improved antifouling performance. The photocatalytic results prove that surface deposition method (95.2%) was better than the blending method (31.1%) for forming high-performance membranes. Therefore, the NGRT@AC-PSF membrane has the potential for broad applications in dye degradation to treat waste water from textile industries.

In this study, polyelectrolyte assembled functionalized graphene oxide (PE-GO) membranes were fabricated through a one-step charge facilitated deposition method for high performance dye/salt separation. According to the intercalation of polydopamine (PDA) and (ionic liquid) IL functional moieties into the GO membranes, the pore size of the resulted PE-pGO and PE-iGO membrane increased from 2.69 nm to 4.13 nm and 6.54 nm, respectively. Correspondingly, a pure water flux of 13.8 ± 2.2, 36.7 ± 3.4, and 52.1 ± 6.7 L m−1 h−1 bar−1 was achieved for PE-GO, PE-pGO and PE-iGO membrane, respectively. PE-iGO membrane with the largest pore size could be operated with significant water permeability (28.3 to 38.3 L m−1 h−1 bar−1) at a low operating pressure range of 0.5–2 bar (dye concentration = 100 ppm, salt concentration = 5 g/L). More importantly, functionalities introduced to the GO nanosheets are found to impact the dye adsorption to the membrane surface. The IL intercalation promotes the elution of dye molecules from the IL moieties at elevated pH, therefore enhancing the efficiency of alkaline washing of the membrane. By contrast, the intercalation of PDA weakens such efficiency due to its strong adhesion force to the dye molecules even at the alkaline condition.

Aquaporin (AQP) based biomimetic membranes have attracted considerable attention for their potential water purification applications. In this paper, AQP1 incorporated biomimetic membranes were prepared and characterized. The morphology and structure of the biomimetic membranes were characterized by in situ atomic force microscopy (AFM), infrared absorption spectroscopy, fluorescence microscopy, and contact angle measurements. The nanofiltration performance of the AQP1 incorporated membranes was investigated at 4 bar by using 2 g l−1 NaCl as feed solution. Lipid mobility plays an important role in the performance of the AQP1 incorporated supported lipid bilayer (SLB) membranes. We demonstrated that the lipid mobility is successfully tuned by the addition of monoolein (MO). Through in situ AFM and fluorescence recovery after photo-bleaching (FRAP) measurements, the membrane morphology and the molecular mobility were studied. The lipid mobility increased in the sequence DPPC < DPPC/MO (RMO = 5/5) < DOPC/MO (RMO = 5/5) < DOPC, which is consistent with the flux increment and salt rejection. This study may provide some useful insights for improving the water purification performance of biomimetic membranes.

A hydrophilic, hydrostable porous metal organic framework (MOF) material-MIL-101 (Cr) was successfully doped into the dense selective polyamide (PA) layer on the polysulfone (PS) ultrafiltration (UF) support to prepare a new thin film nanocomposite (TFN) membrane for water desalination. The TFN-MIL-101 (Cr) membranes were characterized by SEM, AFM, XPS, wettability measurement and reverse osmosis (RO) test. The porous structures of MIL-101 (Cr) can establish direct water channels in the dense selective PA layer for water molecules to transport through quickly, leading to the increasing water permeance of membranes. With good compatibility between MIL-101 (Cr) nanoparticles and the PA layer, the lab made TFN-MIL-101 (Cr) membranes integrated tightly and showed a high NaCl salt rejection. MIL-101 (Cr) nanoparticles increased water permeance to 2.2 L/m2·h·bar at 0.05 w/v % concentration, 44% higher than the undoped PA membranes; meanwhile, the NaCl rejection remained higher than 99%. This study experimentally verified the potential use of MIL-101 (Cr) in advanced TFN RO membranes, which can be used in the diversified water purification field.

The influence of nanocomposite hole-extraction layers on the performance of organic photovoltaic (OPV) cells based on blends of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-61-buytyric acid methyl ester (PCBM) has been investigated. The hole-extraction layers consist of poly(3,4,-ethylene dioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) doped with different concentrations of multiwall carbon nanotubes (MWCNTs). Compared with a pristine device (i.e., without MWCNTs), the MWCNTs-doped OPV cells shows an improved short-circuit current density, fill factor, and power conversion efficiency from 8.82 to 9.03 mA/cm2, 0.43 to 0.474, and 2.12% to 2.39% (i.e., by about 13%), respectively. Reasons for the improved performance of the devices are discussed. It shows that the reduction of series resistance of the devices might be correlated with the improvement of the OPV cells, performance achieved through the incorporation of MWCNTs into the hole-extraction layer of PEDOT:PSS.

Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) doped with multi-walled carbon nanotubes (MWCNTs) films is fabricated on quartz substrates by spin coating method. The effects of MWCNTs on the structure and properties of PEDOT:PSS film have been investigated. X-ray diffractometer (XRD) and Fourier transform Raman spectroscopy (FTRM) show that the crystallization behavior and the main chain of PEDOT:PSS are not changed. Atomic force microscopy (AFM) shows that individual nanotubes are well dispersed in the PEDOT:PSS matrix. Moreover, some nanotubes overlap into a net-like structure, forming new conductive channels, which can enhance efficiently the film conductivity. The conductivity of PEDOT:PSS film doped with a lower percentage of MWCNTs (0.2 wt%) is 9.16 S/cm, higher than that of pure PEDOT:PSS film (0.28 S/cm), although the optical transmission of PEDOT:PSS decreases a little after the addition of MWCNTs. The interaction between MWCNTs and PEDOT:PSS during melt mixing is also given a possible explanation.

Developing ultrafiltration (UF) membranes with excellent anti-biological fouling and overcoming the hydrophobicity of membrane material itself has been a major challenge. While exposing a major drawback of being unstable and easily lost from the membrane, silver nanoparticles (AgNPs) are still used as bactericidal substances in membranes. Polyamic acid (PAA) is a flexible hydrophilic polymer that exhibits strong complexing ability and considerable steric hindrance effect on metal cations. Herein, using PAA as a stabilizer to modify the size and dispersion of silver nanoparticles (AgNPs), we developed a polyethersulfone (PES) UF membrane featuring both hydrophilic and antibacterial dual functions. The AgNPs in the as-prepared membrane were small in size (around 3-10 nm) and highly dispersed in the membrane, exhibiting highly efficient antibacterial ability with 96.82% and 98.29% inhibition towards Escherichia coli and Staphylococcus aureus, respectively. Meanwhile, the partially covered AgNPs by PAA and the high surface energy made them less susceptible to lose in the membrane. The developed membrane retained about 4.5 times more AgNPs than the original membrane for the same membrane area. Moreover, the favorable hydrophilic and pore structure endowed the membrane with high water flux and acceptable rejection of bovine serum albumin (BSA). The PES/PAA-Ag membrane exhibited an excellent water flux, which was 421.47 (L/m2·h) under 1 bar pressure, about 1.4 times of PES and 3.4 times of PES-Ag membrane (with a high BSA rejection, around 90%). This work provided a reference for the development of hydrophilic and antimicrobial membranes, as well as having considerable potential practical value. [ABSTRACT FROM AUTHOR]