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Carbon nanotubes (CNTs) have potential applications in separation membranes and nanofluidic devices. It is well known that the behavior of water molecules confined in CNTs is affected by surface functional groups and external electric fields, leading to structural changes. The understanding of these structural changes of water within various CNTs is crucial, particularly in the context of material separation. While there have been many investigations into the effects of individual specific functional groups, a comprehensive understanding of the effect of these functional groups and the electric fields they generate on water molecules remains elusive. In this study, we investigate the properties of water molecules in tip-charged CNTs of (8,8), (10,10), and (12,12) chiral vectors with positive charges at one tip and negative charges at the other tip. Abstraction of ionized functional groups as tip charges enables a comprehensive understanding that is independent of individual functional groups. The symmetrically arranged tip-charges spontaneously generate a strong and symmetric electric field in the CNTs. However, the strength and directionality of the electric field are non-uniform and complex. In the interiors of (8,8) and (10,10) tip-charged CNTs, helical and square structures, which have disturbances caused by the non-uniformity of the electric field, are observed. The properties of the water molecules differed significantly in the center of the CNTs and near positive and negative charges, despite the electric field symmetry. In (12,12) tip-charged CNTs with 12 charges, a local ring structure is observed in the vicinity of negative charges but not in the vicinity of positive charges. It is concluded that the water structures in tip-charged CNTs have different characteristics from those in plain CNTs under a uniform electric field. [ABSTRACT FROM AUTHOR]

Inspired by biological channels, achieving precise separation of ion/water and ion/ion requires finely tuned pore sizes at molecular dimensions and deliberate exposure of charged groups. Covalent organic frameworks (COFs), a class of porous crystalline materials, offer well-defined nanoscale pores and diverse structures, making them excellent candidates for nanofluidic channels that facilitate ion and water transport. In this study, we perform molecular simulations to investigate the structure and kinetics of water and ions confined within the typical COFs with varied exposure of charged groups. The COFs exhibit vertically arrayed nanochannels, enabling diffusion coefficients of water molecules within COFs to remain within the same order of magnitude as in the bulk. The motion of water molecules manifests in two distinct modes, creating a mobile hydration layer around acid groups. The ion diffusion within COFs displays a notable disparity between monovalent (M+) and divalent (M2+) cations. As a result, the selectivity of M+/M2+ can exceed 100, while differentiation among M+ is less pronounced. In addition, our simulations indicate a high rejection (R > 98%) in COFs, indicating their potential as ideal materials for desalination. The chemical flexibility of COFs indicates that would hold significant promise as candidates for advanced artificial ion channels and separation membranes. [ABSTRACT FROM AUTHOR]

Extreme confinement in nanochannels results in unconventional equilibrium and flow behavior of polymers. The underlying flow physics dictating such paradigms remains far from being understood and more so if the confining substrate is composed of two-dimensional materials, such as graphene. In this study, we conducted systematic molecular dynamics simulations to explore the effect of wettability, confinement, and chain length on polymer flow through graphene-like nanochannels. Altering the wetting properties of these membranes that structurally represent graphene results in substantial changes in the behavior of polymers of disparate chain lengths. Longer hydrocarbon chains (n-dodecane) exhibit negligible wettability-dependent structuring in narrower nanochannels compared to shorter chains (n-hexane) culminating in higher average velocities and interfacial slippage of n-dodecane under less wettable conditions. We demonstrate that the wettability compensation comes from chain entanglement attributed to entropic factors. This study reveals a delicate balance between wettability-dependent enthalpy and chain-length-dependent entropy, resulting in a unique nanoscale flow paradigm, thus not only having far-reaching implications in the superior discernment of polymeric flow in sub-micrometer regimes but also potentially revolutionizing various applications in the oil industry, including innovative oil transport, oil extraction, ion transport polymers, and separation membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The biodegradable surfactant-dodecyl dimethyl betaine (BS-12) was used as metal inhibitor. • Traces of BS-12 (10 mg·L−1) showed high inhibition efficiency (95.3 %) to cold-roll steel (CRS). • The MD simulations showed that the BS-12 adsorbed on the CRS surface horizontally. • The density of state proved that the electron transfer within BS-12 and CRS. • Adding BS-12 had no side effect on the performance of the nanofiltration membrane. The membrane process is an effective way to realize resource reutilization. Most membrane devices are made of cold-roll steel (CRS), which is easy to corrode when operating in acid conditions. Herein, the biodegradable surfactant dodecyl dimethyl betaine (BS-12) was used as the inhibitor to protect the CRS in the trichloroacetic acid (TCA) solution. The long-term stability membrane tests showed that adding BS-12 will not harm the membrane performance. The weight loss experiments proved that adding BS-12 with trace amount (10 mg·L−1) endowed the CRS with good inhibition efficiency (95.3 %). The electrochemical tests indicated that the mixed inhibitor- BS-12 works by inhibiting the anode and cathode simultaneously, and the polarization resistance increased to 21 times. The SEM, AFM, and CLSM tests proved that adding BS-12 enabled the CRS surface to remain stable. The FTIR and XPS tests proved that BS-12 adsorbed on the CRS surface via physical and chemical adsorption. The theoretical calculations proved the horizontal adsorption of BS-12 on the CRS surface and the existence of the electron transfer within the BS-12 and CRS. The BS-12 showed great potential in the CRS inhibition of the membrane separation and purification processing. [ABSTRACT FROM AUTHOR]

Removal of highly toxic chromium ions from water is of utmost necessity. The objective of the present work was to prepare a low‐cost ultrafiltration (UF) membrane for removal of Cr (VI) from water. UF membranes were prepared by phase inversion from the copolymers of acrylonitrile (AN) and partially neutralized acrylic acid (AA)/sodium acrylate (NaAA). Three such copolymers, CP15, CP10, and CP5 were prepared by emulsion polymerization with feed AN: AA/ NaAA molar ratios of 15:1, 10:1 and 5:1, respectively. Silver nanoparticles (AgNP) were incorporated in‐situ during the polymerization by chemical reduction of silver nitrate with ascorbic acid. CP5 and AgNP filled CP5AgNP UF membranes were prepared by varying the polymer concentration in dope solution (Cp), evaporation time (teva) and gelation temperatures (Tgel). Various characterizations confirmed the structure, morphology, presence of AgNP, flux decline and antifouling properties of the membranes. For polymer enhanced ultrafiltration (PEUF), CP5 and CP5AgNP membranes prepared with Cp/teva/Tgel of 13 wt%/90s/30°C with a molecular weight cut off (MWCO) of 7.4 kDa and 5.7 kDa, respectively, showed a pressure normalized flux/rejection of 184.64Lm−2 h−1 bar−1/88.8% and 177.77Lm−2 h−1 bar−1/91%, respectively from a feed containing 100 mg/L of Cr (VI) in the presence of 0.5 wt% PVA. [ABSTRACT FROM AUTHOR]

Nd 2 Ce 2 O 7 is a rare earth oxide with a fluorite structure and exhibits proton conductivity. Alkaline earth metals (Mg, Ca, Sr, Ba) doped Nd 2 Ce 2 O 7 powders were synthesized using the citrate sol-gel method. The doped samples retain the fluorite structure, and enhanced oxygen vacancy concentration. Notably, Nd 1.85 Mg 0.15 Ce 2 O 7-δ exhibited the highest oxygen vacancy concentration, reaching an electrical conductivity of 2.91 × 10−2 S cm−1 in a humid atmosphere of 20%H 2 and 80%N 2 at 900 °C. Hydrogen separation membranes were fabricated using alkaline earth metal-doped Nd 2 Ce 2 O 7 as the proton-conducting phase and Pt as the electron-conducting phase. The results indicated that Pt-Nd 1.85 Mg 0.15 Ce 2 O 7-δ had the optimal hydrogen permeation flux, reaching 8.35 × 10−9 mol cm−2•s−1 at 900 °C. It demonstrated short-term stability in environments containing CO 2 and H 2 O, and an increase in temperature and hydrogen partial pressure on the feed side enhanced hydrogen permeation, highlighting its potential as a hydrogen separation membrane material. [ABSTRACT FROM AUTHOR]

Membrane processes are being considered for carbon dioxide capture from concentrated point sources. The processes often use hollow fiber membranes. Modules are formed by gathering fibers together in a bundle. The fibers may be supplied individually or in small groups (i.e. tows) for module fabrication. The use of tows can introduce nonuniform fiber packing due to the size and spacing of the tows. The potential for flow maldistribution and its detrimental effect on module performance is evaluated by solving the governing conservation equations. For the first time, the performance of a module formed from fiber tows is evaluated. Two performance metrics are reported: 1) recovery and 2) required area as a function of carbon dioxide removal. The effects of tow size and tow spacing are evaluated. The results indicate performance is better for smaller tows. Furthermore, lower packings, both intra- and inter-tow, are preferred. The concept of an equivalent planar bundle (EPB) for fiber tow modules is introduced to potentially reduce simulation time and costs. The simple procedure for creating the EPB is validated by comparing the performance metrics calculated using the EPB to the results obtained from full simulations. [ABSTRACT FROM AUTHOR]

This article examines the effect of CTAB on the interfacial rigidity of silica nanoparticle films at the oil/water interface. The authors demonstrate that increasing CTAB concentrations reduce the rigidity of the nanoparticle layer, which in turn influences the structural integrity of bicontinuous interfacially jammed emulsion gels (bijels). [Display omitted] • CTAB charge screening lowers interfacial rigidity of nanoparticle assemblies. • Modulation of charge screening via ionic strength. • Charge screening also promotes CTAB adsorption on silica nanoparticles. • Interfacial rigidity control enhances bijel uniformity and structure. Functionalizing colloidal particles with oppositely charged surfactants is crucial for stabilizing emulsions, foams, all-liquid structures, and bijels. However, surfactants can reduce the attachment energy, the driving force for colloidal self-assembly at interfaces. An open question remains on how the inherent interfacial activity of cationic surfactants influences the interfacial rigidity of particle-laden interfaces. We hypothesize that charge screening among cationic surfactants regulates the rigidity of oil/water interfaces by reducing the attachment energy of nanoparticles. We investigate the interfacial rigidity of cetyltrimethylammonium bromide (CTAB) functionalized silica nanoparticles (Ludox® TMA) by analyzing the shape deformation of 1,4-butanediol diacrylate (BDA) droplets under varying salt and alcohol concentrations. The nanoparticle packing density is assessed using scanning electron microscopy. Attachment energy is characterized through interfacial tension measurements, three-phase contact angle analysis, and CTAB adsorption studies. We also examine the effects of interfacial rigidities on the structure of bijel films formed via roll-to-roll solvent transfer-induced phase separation (R2R-STrIPS) using confocal laser scanning microscopy. Increasing salt and alcohol concentrations decrease the interfacial rigidity of CTAB-functionalized nanoparticle films by reducing the interfacial tension. The contact angle has a minor influence on the rigidity. These results indicate that CTAB charge screening weakens the nanoparticle attachment energy to the interface. Controlling the rigidity enables the mass production of bijel sheets with consistent flatness, which is crucial for their potential applications in catalysis, energy storage, tissue engineering, and filtration membranes. [ABSTRACT FROM AUTHOR]

Membrane fouling is a major hindrance that restricts the application of membrane bioreactors (MBRs). Bdellovibrio-and-like organisms (BALOs), as obligatory parasitic bacteria, prey upon various bacteria. In this study, the BALO mixtures were screened and found more effective in membrane fouling mitigation compared to the single BALO species and extended the membrane filtration period by as long as 33.3%. The higher BALO diversity reduced the potential foulants generation in the activated sludge by decreasing the sludge viscosity as high as 13.8 ± 0.6% than the pure culture of BALO. Meanwhile, the mixed BALOs demonstrated superior biofilm predation capabilities, with the content of soluble microbial products and extracellular polymeric substances on the biofilm decreasing by 26.1 ± 0.5% and 38.3 ± 0.2% as the most compared to the single BALO species involved system. Additionally, the BALO mixtures expanded the single strains' host lysis spectrum of both the activated sludge and biofilm. The abundance of membrane-fouling-related bacteria such as Flavobacterium, Rhodobacter, and Labilithrix and pioneer bacteria such as Sphingorhabdus and Pseudomonas was significantly reduced. In summary, this study disclosed the significantly better membrane fouling mitigation effects of the BALOs with higher diversity, suggesting that the expansion of the host range is crucial for the further application of BALOs to enhance the anti-fouling performance of the MBR system. [ABSTRACT FROM AUTHOR]

ABSTRACT The demand for lentiviral vectors (LVs) as tools for ex vivo gene therapies is ever‐increasing. Despite their promising applications, challenges in LV production remain largely due to the fragile envelope, which challenges the maintenance of vector stability. Thus, downstream processing optimization to enhance efficiency, yield, and product quality is necessary. This study investigated the influence of membrane types and filtration devices during ultrafiltration (UF). Nine different membrane materials consisting of polyethersulfone (PES), regenerated cellulose, or Hydrosart, with distinct molecular weight cutoffs, were evaluated in stirred cells, centrifugal ultrafilters, and crossflow cassettes. The evaluation was based on the ability to retain infectious LV particles and remove impurities. The analysis revealed that a reinforced 100 kDa PES and a 300 kDa Hydrosart membrane had the best overall ability to concentrate infectious LVs and remove DNA, especially when operated in a stirred cell. Challenges were seen in the nonoptimized crossflow cassette process, where infectious LV recovery was generally lower compared to other devices. We demonstrated that membrane material and filtration device have a direct impact on the efficiency of LV UF. [ABSTRACT FROM AUTHOR]

This study focuses on the fabrication and characterisation of single-walled carbon nanotube (SWCNT) buckypapers and polyethersulfone (PES) flat-sheet membranes using Cyrene, aiming toevaluate its efficacy as a green solvent for these applications. Pristine SWCNTs were dispersed inCyrene without surfactants and compared to N-Methyl-2-pyrrolidone (NMP) dispersions. Buckypapers were fabricated from these dispersions and characterised using Scanning ElectronMicroscopy (SEM), Atomic Force Microscopy (AFM), and infrared spectroscopy. Their performancewas tested in wastewater and oil-water emulsion filtrations and antimicrobial activity. PESmembranes incorporating SWCNTs were prepared using phase inversion and analysed via SEM,optical microscopy, and contact angle. Membrane properties and water permeability were assessed,and bacterial challenge tests evaluated antimicrobial activity. Cyrene enabled the dispersion ofSWCNTs at higher concentrations (0.038 mg mL⁻1) compared to NMP (0.013 mg mL⁻1). Transmission Electron Microscopy (TEM) analysis revealed that Cyrene effectively debundles SWCNTs, yielding better dispersion. Buckypapers fabricated with Cyrene demonstrated dense, uniform networks with enhanced surface smoothness and promising filtration performance for wastewater treatment and oil-water separation. PES membranes made with Cyrene exhibited well-organised finger-like structures, interconnected pores, superior porosity, and higher water permeability than NMP-based membranes. Incorporating SWCNTs further improved membrane performance. However, bacterial challenge tests indicated no significant antimicrobial activity. The findings highlight Cyrene's potential as a sustainable alternative to traditional solvents, offering improved material properties and filtration performance. Despite these advantages, further studies are necessary to address solvent residuals and long-term safety considerations, ensuring its suitability for broader applications. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants have two persistent financial and energetic drains, the carbon dioxide content of biogas, which limits its commercial sale, and the presence of trace organics in the wastewater effluent, which damages the aquatic ecosystem, like the Great Barrier Reef. Biogas is a renewable methane resource that is underutilized due to the variable CO2 content (~40%). Biogas is energy intensive to purify and limited by the economy of scale (> 8.85 GJ/h) to large‐scale purification methods, thus small‐scale processes require development. Electrocatalytic microbes native to wastewater have been shown to convert CO2 to CH4 and acetate, however complete conversion of the CO2 content to CH4 is energy intensive. Here we show a low power bioelectrochemical fuel cell design to purify biogas to pipeline quality methane (98%), manufacture methane and/or acetate, and remove trace organics, using HCO3− as the transport charge carrier from dissolved CO2 from the biogas through an anion exchange membrane. This decreased the power required to separate CO2 from methane in biogas on a molar basis, resulting in a net energy recovery similar to current industrial systems. Magnesium anode use resulted in an energy positive system. Tests evaluated the influence of cathode potential on the current density, HCO3− ion flux and the rates and efficiencies of methane production, resulting in optimization at −0.7 V versus standard hydrogen electrode (SHE). A techno‐economic analysis modeled a positive return on investment for scaled‐up production to purify small biogas streams that are otherwise financially unrecoverable. Carbon sequestration by production of methane, acetate and solid fertilizers demonstrated profitable and energy efficient waste‐to‐resource conversion. Methane is manufactured from carbon dioxide simultaneous to biogas purification for carbon neutral energy production in a biological fuel cell during the final process step of wastewater treatment. Lab tests demonstrate proof of concept during wastewater treatment. The techno‐economic analysis (financial and manufacturing model) demonstrates industrial scale operation can make a profit at manufacturing renewable methane and/or acetate. [ABSTRACT FROM AUTHOR]

The emulsions of water-insoluble organic compounds such as oil and fatty alcohol based solvents, are widely encountered in chemical industries and this type of emulsions have led to significant environmental pollution. Therefore, it is crucial to explore effective approaches for removal of waste oil and other fatty solvents present in aqueous emulsions. In this study two types of aqueous emulsions were studied to separate water; water/oil and 1-decanol/water emulsions. A vacuum membrane filtration system was used to separate the emulsions. Bacterial cellulose (BC) membranes were synthesized using Gluconacetobacter xylinus bacteria. Our findings demonstrate that BC membranes can effectively separate water from oil and fatty alcohol based solvent containing emulsions, thereby providing a viable solution for environmental remediation. [ABSTRACT FROM AUTHOR]

Thin-film composite polyamide (TFC PA) membranes hold promise for energy-efficient liquid separation, but achieving high permeance and precise separation membrane via a facile approach that is compatible with present manufacturing line remains a great challenge. Herein, we demonstrate the use of lignin alkali (LA) derived from waste of paper pulp as an aqueous phase additive to regulate interfacial polymerization (IP) process for achieving high performance nanofiltration (NF) membrane. Various characterizations and molecular dynamics simulations revealed that LA can promote the diffusion and partition of aqueous phase monomer piperazine (PIP) molecules into organic phase and their uniform dispersion on substrate, accelerating the IP reaction and promoting greater interfacial instabilities, thus endowing formation of TFC NF membrane with an ultrathin, highly cross-linked, and crumpled PA layer. The optimal membrane exhibited a remarkable water permeance of 26.0 L m-2 h-1 bar-1 and Cl-/SO42- selectivity of 191.0, which is superior to the state-of-the-art PA NF membranes. This study provides a cost-effective scalable strategy for fabricating ultra-selective and highly permeable NF membrane for precise ion-ion separation and small organic compounds removal. Achieving high permeance and precise separation in thin-film composite polyamide (TFC PA) membranes remains challenging. Here, the authors demonstrate the use of lignin alkali derived from waste of paper pulp as an aqueous phase additive to regulate interfacial polymerization process for achieving high performance nanofiltration membranes. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) combining functional fillers with polymer matrices hold promise for high‐efficiency separation. However, it remains a great challenge to enhance the loading to fully harness the capabilities of the fillers. Herein, we introduced RUB‐15 nanosheets as fillers for MMMs to approach parallel alignment of nanosheets within the matrix, thus achieving a high‐loading rate of up to 55 wt% and constructing fast and continuous mass transfer channels. The parallel orientation reduced the occurrence of defects, which played a critical role in enhancing separation. An optimized membrane with a 50 wt% loading rate exhibited exceptional H2/CO2 gas separation performance with H2 permeability of 1934 Barrer and selectivity of 44.5, maintaining a separation factor of 16.7 at 125°C. This study maximizes the performance of porous functional fillers within the membrane by enhancing gas separation capabilities through the ordered alignment of nanosheets and provides valuable insights for future membrane development. [ABSTRACT FROM AUTHOR]

The recent advancement in mechanically and chemically robust membranes has led to the capabilities of both reverse osmosis (RO) and pervaporation (PV) for separation of water/organic solvent and organic solvent mixtures. However, their performances are evaluated in different permeation formulas. To address this, we have conducted an analysis using a unified parameter: activity‐based permeance. The present study evaluated RO and PV using the same organosilica membrane for the separation of both non‐aqueous solvents (methanol/ethanol, methanol/iso‐propanol [IPA], and methanol/dimethyl carbonate) and organic solvent‐aqueous mixtures (including water with methanol, ethanol, IPA, tert‐butanol, and glucose), at concentrations ranging from 0% to 100%. With the use of activity‐based permeance, we achieved a consistent evaluation of both PV and RO processes. Moreover, this approach provides prediction of separation performance even in RO and PV. [ABSTRACT FROM AUTHOR]

3D covalent−organic framework (3D COF) membranes have unique features such as smaller pore sizes and more interconnected networks compared with 2D COF counterparts. However, the complicated and unmanageable fabrication hinders their rapid development. Molecular simulation, which can efficiently explore the structure‐performance relationship of membranes, holds great promise in accelerating the development of 3D COF membranes. In this study, a series of 3D‐COF membranes (TFPM‐Pa‐X) is designed with different charge densities (fully charged, partially charged, and neutral) and interpenetration numbers (2‐, 3‐, 4‐, and 5‐fold), subsequently investigate their contributions to Li+/Mg2+ separation through molecular simulation. Membrane morphology and pore size are found to strongly depend on the charged density and interpenetration number. The pore size and Cl− ion density play a crucial role in governing membrane separation performance. TFPM‐Pa‐X membrane with a smaller interpenetration number and a higher charge density promotes Li+/Mg2+ separation. The fully charged 2‐fold interpenetrated membrane has superior performance in breaking the trade‐off between the flux of Li+ (JLi+) and the selectivity of Li+ over Mg2+ (SLi+/Mg2+). This study may facilitate the rational design of new 3D COF membranes for high‐performance ion separation. [ABSTRACT FROM AUTHOR]

This study describes the use of the emulsion liquid membrane (ELM) technique to recover thorium (Th(IV)) from an aqueous nitrate solution. The components of the ELM were kerosene as a diluent, sorbitan monooleate (span 80) as a surfactant, bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) as an extractant, and H2SO4 solution as a stripping reagent. Th(IV) was more successfully extracted and separated under the following favorable conditions: Cyanex272 concentration of 0.11 mol/L; 0.65 mol/L H2SO4 as a stripping phase (internal phase); feed phase (external phase) pH of 1; internal-to-membrane phase volume ratio of 1; emulsion-to-external phase volume ratio of 0.4; contact time of 25 min; and agitation speed of 300 rpm. Under these conditions, the membrane transferred Th(IV) selectively from the real leach liquor without appreciable emulsion breakage or swelling. [ABSTRACT FROM AUTHOR]

Zeolite membranes are considered ideal inorganic membrane materials for separating mixtures with molecular‐level differences. However, their complex preparation process with excessive synthesis solutions for traditional hydrothermal heating methods leads to various drawbacks. Here, we describe a membrane preparation strategy involving an in situ interfacial transformation of the protomembrane without solvents. Inexpensive clay powder forms the protomembrane, and the active ingredients subsequently migrate from the interior of this protomembrane to its surface and transform into a zeolite layer. Ultimately, the protomembrane is calcined to obtain the support‐layer integrated zeolite membrane. Systematic research shows that clay not only serves as a raw material for the support but also provides active ingredients for the growth of zeolite crystals; thus, zeolite membranes with zeolite particles inserted into the support are formed. The zeolite membrane calcined at 800 °C possesses a p‐xylene/o‐xylene separation factor approaching 6263 with a permeation flux of 1.21×10−7 mol ⋅  m−2 ⋅  s−1 ⋅  Pa−1. This interfacial transformation method can be applied to other membranes and promote the development of membrane separation technology. [ABSTRACT FROM AUTHOR]