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Acid‐alkaline amphoteric water electrolysis (AAA‐WE) can produce green hydrogen under reduced voltage and energy consumption. However, its conflicting demands on ion exchange membranes to have both high ionic conductivity and barrier properties between H+ and OH− have thwarted its own development. Here, the preparation of anisotropic polybenzimidazole (PBI) ion‐solvating membrane (ISM) made of hundreds of 28 nm thick nano‐sheets (PBI‐aNS) from gel state PBI (PBI‐Gel) membranes via 2D‐polarized/1D shrinking process, in which loosely packed multi‐layer PBI nano‐fibrous assemblies are shrunken into hundreds of layers of tight 28 nm thick nano‐sheets, is reported. The resulting PBI‐aNS membranes possess excellent dual‐ion conductivity (H+ and OH−), good acid/alkali barrier capability, and robust mechanical properties. Acid‐alkaline amphoteric water electrolysis (AAA‐WE) using PBI‐aNS separators achieves a high current density of 1 A cm−2 at 1.4 V (with iR‐correction) under a voltage increasing rate of 6.1 mV h−1. This newly designed ISM will lead to new possibilities for the development of next‐generation water electrolysis devices with improved green hydrogen production efficiencies. [ABSTRACT FROM AUTHOR]

Preparation of porous cement-based materials via freeze casting is a process with great potential. However, freeze-drying and steam curing complicate the preparation process and increase the preparation period. To simplify the process, heat-dry curing was used for replacing freeze-drying and steam curing during operation. The new preparation method combined freeze casting and heat-dry curing possesses characteristics of low-energy, simplicity, and time-saving. Compared with the traditional preparation method of porous cement-based materials, the novel preparation process can shorten preparation time by at least 16 % and retrench energy consumption by at least 18 %. As the improvement condition, temperature of heat-drying curing has great influence on the structure and performance of the samples. Therefore, it is of great significance to discuss the relationship between heat-dry temperatures and structural parameters by SEM, N 2 -adsorption/desorption, TG, and ATR-FTIR. Lamellar pores of membranes can be easier observed at low temperatures than that at 100 °C. The separation performance of oil-water is generally improved with the increase of temperature. Meanwhile, the molecular dynamics simulation was operated to illustrate the reaction mechanism of hydration with three temperatures. This study probably provides more theoretical basis for expanding the application of porous silicate cement membranes. [Display omitted] • Novel coupled method simplifies the fabricating process complexity of cement-based samples. • Influences of heat-dry curing temperatures on porous silicate cement membranes are discussed. • Silicate cement membranes own excellent permeation, oil-water separation and mechanical strengths. • Influences of heat-dry curing temperatures are illustrated by using molecular dynamics. [ABSTRACT FROM AUTHOR]

Preparation of porous cement-based materials via freeze casting is a process with great potential. However, freeze-drying and steam curing complicate the preparation process and increase the preparation period. To simplify the process, heat-dry curing was used for replacing freeze-drying and steam curing during operation. The new preparation method combined freeze casting and heat-dry curing possesses characteristics of low-energy, simplicity, and time-saving. Compared with the traditional preparation method of porous cement-based materials, the novel preparation process can shorten preparation time by at least 16 % and retrench energy consumption by at least 18 %. As the improvement condition, temperature of heat-drying curing has great influence on the structure and performance of the samples. Therefore, it is of great significance to discuss the relationship between heat-dry temperatures and structural parameters by SEM, N 2 -adsorption/desorption, TG, and ATR-FTIR. Lamellar pores of membranes can be easier observed at low temperatures than that at 100 °C. The separation performance of oil-water is generally improved with the increase of temperature. Meanwhile, the molecular dynamics simulation was operated to illustrate the reaction mechanism of hydration with three temperatures. This study probably provides more theoretical basis for expanding the application of porous silicate cement membranes. [Display omitted] • Novel coupled method simplifies the fabricating process complexity of cement-based samples. • Influences of heat-dry curing temperatures on porous silicate cement membranes are discussed. • Silicate cement membranes own excellent permeation, oil-water separation and mechanical strengths. • Influences of heat-dry curing temperatures are illustrated by using molecular dynamics. [ABSTRACT FROM AUTHOR]

Isoporous block copolymer membranes with high porosity and narrow pore size distribution have been viewed as ideal membrane platforms for precise separation of similarly sized particles or solutes. However, tailored made fabrication of solvent-resistant isoporous membranes with switchable pores and rigid pores for customizable sieving have been rarely reported. Herein, we show that site-selective hyper-crosslinking is effective and robust to prepare such membranes from polystyrene- block -poly(4-vinylpyridine) (PS- b -P4VP). The selective crosslinking in PS domains endows the membrane with excellent solvent resistance and structural stability. Since not participated in the crosslinking reaction, the P4VP brushes located in pore walls endow the crosslinked membranes with adaptive pore size, switchable permeance and tunable rejections that vary with Hansen solubility parameter of solvents. Moreover, by a facile while complete etching the P4VP from pores, the switchable performance is removed and resultant membranes show rigid pore characteristics and constant rejections. Crosslinked membranes with either switchable pores or rigid-likes pores exhibit superior long-term stability (30 days) in harsh solvents. This work presents a top-down method to construct highly stable isoporous membranes with both switchable and rigid pore characteristics from the same block copolymer, which will shed the light on precisely tailoring the pore size and pore rigidity for crosslinked isoporous membranes that will not only enable the tailored sieving but also the modelling of solvent flowing behaviours in nanopores. [Display omitted] • Site-selective hyper-crosslinking is developed to prepare the solvent-resistant isoporous membranes. • Hyper-crosslinked isoporous membranes display an excellent structural stability in a wide range of polar solvents. • Functional nanopores with solvent-responsiveness and tunable sieving in isoporous membranes are revealed. • Degrade the polymer brushes in nanopores endows the membranes with rigid pores and constant separation behaviors. [ABSTRACT FROM AUTHOR]

The cosolvent-assisted interfacial polymerization (CAIP) has garnered significant attention due to its capacity to easily and effectively modify the performance of polyamide (PA) reverse osmosis (RO) membranes. To gain deeper understanding of the mechanism of a specific type of cosolvents on the IP reaction, namely N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N,N-dimethylpropionamide (DMPr) were used as aqueous-phase cosolvents to systematically investigate their effects on the membrane structures and properties under different conditions. Amide cosolvents in the aqueous phase facilitated the diffusion of the amine monomer and the formation of nanovoids within the PA layer as the C-chain length of amides increased. When 1,2-dichloroethane was also included in the organic phase, the extent of the two-phase miscible zone was further increased with its assistance, which contributed to generating the larger nanovoids within the layer, thicker PA layer and extensive exterior PA layers, as well as significantly enhancing the water permeability and selectivity of membranes. Importantly, this study successfully prepared high-performance RO membranes with multilayer nanovoid structures in situ by introducing cosolvents in the IP reaction with permeability up to 2.26 L·m−2·h−1·bar−1, providing theoretical and experimental bases for further enrichment of CAIP. [Display omitted] • Exploring the effects of different amides on the diffusion of amine monomers. • Longer chain DMPr contributes to the formation of multilayered nanovoid structures. • Correlating amine monomer diffusion rate with PA layer evolution. • TFC a-o -DMPr shows water permeability of 2.26 LMH/bar and NaCl rejection of 98.38 %. [ABSTRACT FROM AUTHOR]

The robust correlation between the performance of thin-film composite (TFC) reverse osmosis membranes and the polyamide (PA) active layer determines the necessity of precise design of the PA layer, and this regulation primarily involves the surface morphology and internal characteristics of the PA layer. In this study, we fabricated honeycomb Turing structure or nanovoid-rich TFC series membranes using polar/nonpolar organic phase additives. Characterization and simulation results confirmed that the enhancement of membrane performance relied more on the abundant nanovoids within the PA layer rather than the ordered honeycomb lattice surface. Notably, the TFC-nDCE membrane with multilayer nanovoids exhibited an approximately 89 % improvement in water permeability while maintaining satisfactory salt rejection (98.29 %). We emphasized the significant role of nanovoids in the diffusion process of amine monomers and investigated the potential relationship between nanovoids and the degree of surface cross-linking. Building upon this, a new insight into the formation of nanovoids induced by PA anisotropic growth was presented through a careful analysis of the amine monomer diffusion rate and the morphological evolution of nanovoids. The structure-property relationship between internal structures, surface morphologies, and performances was systematically and thoroughly investigated, pointing out the direction for the rational design of TFC membranes. [Display omitted] • Revealed effects of nanovoids on the water/salt flow in honeycomb Turing PA layer. • Impacts of nanovoids on the physicochemical structure of PA layer were emphasized. • New insights on the anisotropic growth of PA were provided. [ABSTRACT FROM AUTHOR]

For nanofiltration (NF) membranes, constructing the interlayer between the substrate and polyamide (PA) layer could balance the trade-off effect between the selectivity and permeability. However, the influencing mechanism of the interlayer to the PA layer is mostly indirect, and how to regulate the physicochemical properties of the PA layer to improve the membrane property remains to be investigated. In this study, porous Zn-TCPP nanosheets with active reaction sites were used to construct interlayer and directly participated in interfacial polymerization (IP) reaction through the edge COOH of nanosheets reacting with piperazine (PIP) to further regulate PA layer physicochemical properties. Controlling the amount of nanosheets involved in the reaction, NF membranes with striated Turing structures, higher negatively charged surface and larger effective filtration area were obtained. The NF membrane permeability with Zn-TCPP interlayer was significantly improved by 123 % while the Cl−/ SO 4 2 − selectivity was greatly enhanced to 72.69, meanwhile it showed excellent performance stability. This study presents a new perspective that the interlayer can modulate the NF membrane physicochemical properties to improve its performance by directly participating in the IP reaction. [Display omitted] • Porous Zn-TCPP interlayer directly participates in the IP reaction via peripheral carboxyl groups. • Zn-TCPP interlayer reduces the pore size of substrate and inhibits the downward growth of polyamide. • Surface morphology of NF membranes is changed, and hydrophilicity and electronegativity are enhanced. • Zn-TCPP interlayer improves the selectivity of NF membrane for mono-/di-anions. [ABSTRACT FROM AUTHOR]

Tight ultra-filtration (TUF) membranes were constructed by in situ growing zinc imidazole frameworks micro-crystalline leaves (ZIF-L) in polyethylene imine (PEI) and polydopamine (PDA) deposit layers on porous polyethylene (PE) substrates. The effects of preparation conditions on the surface physical and chemical structures as well as on the dye/salt separation performance of the formed TUF membranes were systematically investigated. By inserting selective water permeation channels and increasing contacting surface areas, in situ-grown ZIF-L arrays tightly cross-linked in the coating matrix greatly increased water permeation without trading off dye/salt retention selectivity. The morphology of the included ZIF-L particles could be varied by adjusting the ligand/Zn molar ratio (α) in the preparation processes. Optimized PDA-PEI/ZIF-L@PE TUF membranes containing ZIF-L of cross-cross block morphology showed very high pure water permeability of 180 ± 20 L·m−2·h−1·bar−1 (LMHB) and retention selectivity (S CR/Na2SO4 and S MB/Na2SO4) of 267 and 43, respectively, as well as excellent stability and anti-fouling properties. [Display omitted] • Lower cost-based TUF membranes were prepared for effective dye/salt separation. • In situ-grown ZIF-L increased water flux without losing dye retention selectivity. • PEI and PDA coating greatly enhanced the stability of ZIF-L in water. • Morphology of ZIF-L was tuned for improving membrane performance. • Protonation of the -NH- groups increased positive charge and water flux. [ABSTRACT FROM AUTHOR]

Organic solvent forward osmosis (OSFO) is a newly developing technology for recovering the organic solvent and concentrating substances. The commercial polyethylene (PE) battery separator is the ideal support for OSFO owing to the low structural parameter, resistance for organic solvents, commercially available and simple preparation process. A novel thin-film nanocomposite (TFN) membrane for OSFO was fabricated on the dopamine (DA)-modified PE support by adding α-cyclodextrin (α-CD) in the polyamide (PA) layer. The inclusion complexes (MPD@α-CD) formed by host-guest chemistry enhanced the stability of the membrane. Because of the Janus path and molecular sieving effect of α-CD, the TFN membrane exhibited superior permeability and selectivity among the recent reports. Moreover, the TFN membrane showed high rejection of Rhodamine B and Oxytetracycline, so it had great potential for solutes concentration. Herein, this work broadens the application of eco-friendly α-CD in membrane field and improves the PE composite membrane for OSFO process. [Display omitted] • PE battery separator can withstand organic solvents and reduce ICP. • α-Cyclodextrin slows down the diffusion of MPD through host guest reactions with MPD. • The ethanol flux of TFN membrane reaches at 3.92 L·m−2·h−1. • TFN membrane show excellent stability and great potential for concentration solutes in organic solution. [ABSTRACT FROM AUTHOR]

Composting is a process of converting potentially harmful organic matter into harmless organic fertilizer through microbial fermentation. This process enables the rational use of resources and represents an embraced technology marked with sustainable development features. Hindering ammonia emissions during composting is vital, as ammonia is a valuable resource and harmful if emitted excessively. Polytetrafluoroethylene (PTFE) membranes are often used as functional covering membranes to prevent ammonia produced by composting from releasing due to its hydrophobicity. However, they are susceptible to oily aerosols in oily composting, which affects microbial decomposition in aerobic composting. Thus, the development of amphiphobic PTFE membrane is necessary and meaningful. For the amphiphobic PTFE membrane, an important issue is the amphiphobic stability of the membrane, especially in the special alkaline environment of composting. Herein, we suggest the use of the polymer to wrap around nanoparticles and PTFE membrane fibers to prepare stable amphiphobic membranes as functional covering membranes for oil-containing composting. Poly(methyl-3,3,3-trifluoropropylsiloxane) (PTFPMS) and 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFTS) entangled with each other and then wrapped the nanoparticles and membrane fibers to form stable amphiphobic membranes with high roughness and low surface energy. The prepared membrane had high liquid repellency to water (～152.8°), diiodomethane (～127.5°), and n-hexadecane (～127.0°). This membrane also possessed a high anti-oil fouling. Moreover, the membrane amphiphobicity exhibited a high stability. This is attributed to the stable fixation of nanoparticles on PTFE membrane fibers with PFTS/PTFPMS. Therefore, the amphiphobicity of the membrane was not affected by ammonia. As for the ammonia filtration efficiency, the amphiphobic membrane had a filtration efficiency of 77.4 % within 10 min, an increase of 6.8 % compared to the PTFE membrane, demonstrating the potential of the membrane we developed toward hindering ammonia emission. This work provides a new way of developing high-performance membrane for the oily composting process. [Display omitted] • An amphiphobic PTFE membrane was developed for oily composting. • The membrane repelled both water and oil highly because of low surface energy and high roughness. • The polymer wrapped the nanoparticles and membrane fibers to form a stable amphiphobic PTFE membrane. • The developed membrane exhibited a good ability for hindering ammonia emission. [ABSTRACT FROM AUTHOR]

The development of reverse osmosis (RO) membranes with both high permeability and selectivity is a key goal for RO technology, the leading water treatment technology. This work presents a simple and cost-effective method for improving RO membrane performance obviously via introducing a hydrophobic small molecule, benzoic acid (BA), in the polyamide (PA) separation layer. The introduction of BA is achieved by adding it in the oil phase of the interfacial polymerization technology because of its oil solubility, which is pretty simple. The hydrophobicity and self-assembly characteristic of BA could establish hydrophobic microenvironments within the PA separation layer. The hydrophobicity of this microenvironment can reduce the number of hydrogen bonds between water molecules, accelerating the rapid transport of water and thereby enhancing membrane performance. Concurrently, BA as a small molecule could moderately increase the space between PA chains and thus enlarge the free volume of hydrophobic microenvironment region, which is also in favour of the improvement of membrane flux. The as-developed RO membrane possessed both high rejection rate (with a NaCl rejection rate of 98.9 %) and high flux (91.7 L m−2 h−1) under the brackish water testing condition, surpassing the performance of many previously reported membranes, and noticeably, a flux increase of 113 % was achieved by utilizing BA. Besides, the performance showed a good long-term stability. It is worth mentioning that small molecules are generally purchasable and cheap, which is beneficial to the large-scale production. This work showcased the great potential of hydrophobic small molecules in improving PA water treatment membrane performance, paving the way for diverse small molecules to develop PA water treatment membrane with both high permeability and selectivity. [Display omitted] • A strategy to improve the RO membrane performance by using small molecule to construct hydrophobic microenvironment in the separation layer was proposed. • The free volume of separation layer was enlarged by the small molecule (benzoic acid). • The microenvironment constructed by benzoic acid had evident hydrophobic characteristic. • The membrane flux was improved obviously by 113 % to 91.7 L m−2 h−1 and meanwhile a high NaCl rejection of 98.9 % was maintained. [ABSTRACT FROM AUTHOR]

Macroporous substrates have great potential in the development of high performance thin film composite forward osmosis (TFC FO) membranes. This paper reports on the preparation of TFC FO membrane via support-free interfacial polymerization (SFIP) technology on a macroporous substrate. SFIP technology can effectively break the bottleneck of conventional interfacial polymerization (IP) technology, which makes it difficult to form a complete polyamide (PA) film on the macroporous substrate. Briefly, the complete PA film is formed at the free water-organic phase interface and then attached to the macroporous substrate by vacuum filtration. The monomer concentration and filtration pressure were adjusted to form the optimal SFIP-PA film. Meanwhile, we chose a macroporous polyvinylidene fluoride (PVDF) microfiltration substrate and screened the pore size to reduce the structural parameters and then the internal concentration polarization, which caused the improvement of water flux. The performance of SFIP-PVDF membranes was investigated and discussed. Under the AL-FS mode with DI water and 1.0 M NaCl solution as the feed solution and draw solution, respectively, the SFIP-PVDF membrane, which used a macroporous PVDF substrate with a pore size of 0.45 μm exhibited a water flux (20 L/m2·h) and a reverse salt flux (2.5 g/m2·h). Besides, the membrane showed good stability in the 72 h test. The specific salt flux (J s /J w) of SFIP-PVDF membranes was much lower than that of IP-PVDF membranes prepared via IP technology, which were incomplete and defective, suggesting that SFIP technology was superior to IP technology. This work effectively exploits the potential of macroporous substrates for the development of high performance TFC FO membranes and provides an insight into the high performance FO membrane design. [Display omitted] • Support-free interfacial polymerization (SFIP) technology was proposed to prepare FO membranes on macroporous substrates. • Macroporous substrates with a pore size of 0.45 μm had high porosity and low tortuosity. • Low ICP, high water flux, and low reverse salt flux were exhibited. • SFIP technology was superior to IP technology on macroporous substrates. [ABSTRACT FROM AUTHOR]