Polyamide Membrane Surface Research Articles

Grafting modification of thin-film composite membrane with quaternary ammonium polyelectrolyte for Mg2+/Li+ separation

The positively charged nanofiltration membrane (NF) has a strong repulsive effect on divalent magnesium ions, thus could be applied for the separation of Mg2+/Li+. Chemical grafting modification is an effective way to prepare positively charged membranes. However, it is difficult to achieve chemical modification on the surface of polyamide membrane as the chemical stability of polyamide. By introducing hydroxyl rich monomers (3-[n-tris(hydroxymethyl)methylamino]−2-hydroxypropanesulfonic, HMAH) as active sites in the interfacial polymerization process, the olefin monomers containing quaternary ammonium salt functional groups (acryloxyethyl trimethyl ammonium chloride, ATA) were reacted onto the surface of NF membrane through radical polymerization initiated by cerium ions to obtain positively charged NF membrane. The successful grafting reaction of quaternary ammonium salt monomer onto the surface of NF membrane was verified by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The membrane with dense and smooth surface layer showed C-N+ characteristic peak in XPS N1s spectra and high isoelectric point. Meanwhile, the as-prepared membrane achieved high MgCl2 rejection of 95.74% and low LiCl rejection of 18.1%, with pure water permeance of 9.43 L·m−2·h−1·bar−1. After 60 hours of mixture filtration experiment, the membrane exhibited good long-term stability, maintaining the ionic separation selectivity over 30, which indicated that the positively charged membrane prepared by grafting method has potential application in the separation of Mg2+/Li+.

Polyamide nanofiltration membranes mediated by mesoporous silica nanosheet interlayers display substantial desalination performance enhancement

Recently, thin-film nanocomposite membranes with interlayered structures (TFNi) have demonstrated great promise for breaking the permeance-selectivity trade-off in nanofiltration (NF). Here, we first report the polyamide (PA) nanofiltration membranes mediated by mesoporous silica nanosheet (MSNS) interlayers. According to the characterizations and chemical analysis, it suggested that the inclusion of MSNS greatly affected the PA membrane surface topography and chemical structure, leading to an enhancement in surface roughness, hydrophilicity, and negative charge and a reduction in crosslinking degree and thickness of the PA layer. Ultimately, the fabricated optimal membrane displayed a favorable combination of high water permeance of 22.5 L m−2 h−1 bar−1 (2.5 times higher than pristine PA) and satisfactory Na2SO4 rejection of 97.8 %, superior to most of the TFNi membranes reported so far when compared by NaCl/Na2SO4 permeation selectivity versus water permeance. Additionally, the MSNS aided design endowed the TFNi membranes with drastically improved antifouling property and high operational stability. Also, the structural advantages of MSNS were highlighted by conducting a control experiment with zero-dimensional (0D) silica nanoparticles. This work is expected to stimulate the use of silica-based nanomaterials for preparing high-performance NF membranes for efficient desalination.

Secondary interfacial reaction of p-aminodiphenylamine enables polyamide reverse osmosis membrane with enhanced and regenerative chlorine resistance

Developing polyamide (PA) reverse osmosis (RO) membrane with chlorine resistance is of great significance for simplifying pretreatment processes and saving operating costs. Herein, we constructed an active layer capable of highly chlorine stability and regenerative chlorine resistance by introducing p-amino diphenylamine (p-ADA) with redox activity via a facile secondary interfacial reaction (s-IR) on PA membrane surface. The calculation of resistance-in-series model indicated that the introduction of p-ADA facilitated the increase of NaCl transmembrane resistance without sacrificing membrane permeance. Chlorination experiments under acid conditions proved the protection effect of p-ADA grafted layer due to its oxidation resistance, avoiding the direct attack by free chlorine to amide bonds of polyamide membrane. By virtue of the convertible modality of the p-ADA molecule between the quinone and benzene structures during redox process, modified membranes presented the capability of regenerative chlorine resistance. After the “chlorination-reduction” cycle experiments, the normalized flux of modified membranes remained 0.522 while contrasted PA membranes showed a flux of 0.278; and the corresponding normalized NaCl rejection of modified membranes maintained at 0.998 significantly higher than that of PA membranes (0.963). This study presents a straightforward and efficient approach to enhance the chlorine resistance of PA RO membranes.

Orientation matters: Measuring the correct surface of polyamide membranes with quartz crystal microbalance

The surface of polyamide reverse osmosis (RO) membranes which regulates interface-dominated phenomena, such as partitioning and fouling, is the one facing the feed during operation. However, the opposite surface of the polyamide selective layer, the one facing the permeate and in contact with the polysulfone porous support, is commonly analyzed in quartz crystal microbalance (QCM) measurements due to limitations of state-of-the-art transfer methodologies. Such measurements on the back surface cannot be generalized because the polyamide layer is chemically and morphologically asymmetric. Herein, we introduce a simple method to coat QCM sensors with polyamide active layers in the correct orientation (i.e., exposing their front surface) and show that interface-dominated phenomena differ significantly between orientations. We start by describing a transfer protocol to coat any surface with a polyamide layer on its front surface orientation. We then systematically analyze the chemical and morphological differences between the two surfaces of the polyamide layer of a commercial RO membrane. Finally, we demonstrate that interface-dominated phenomena depend on the orientation by showing that NaCl partitioning at pH 6 was 1.3 to 2.3-fold higher on the front surface and that organic fouling with humic acid occurred at a lower rate on this surface. The new method presented herein enables measurements on the front surface of polyamide RO membranes, which should be the standard in any future QCM studies.

Microfiltration Membranes Modified with Zinc by Plasma Treatment.

Polymer membranes play an important role in various filtration processes. The modification of a polyamide membrane surface by one-component Zn and ZnO coatings and two-component Zn/ZnO coatings is presented in this work. The technological parameters of the Magnetron Sputtering-Physical Vapor Deposition method (MS-PVD) for the coatings deposition process show an impact on the influence on the membrane's surface structure, chemical composition, and functional properties. The characterization of surface structure and morphology were analyzed by scanning electron microscopy. In addition, surface roughness and wettability measurements were also made. For checking the antibacterial activity, the two representative strains of bacteria Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) were used. The filtration tests showed that polyamide membranes covered with three types of coatings, one-component Zn coatings, ZnO coatings, and two-component Zn/ZnO coatings, presented similar properties. The obtained results show that using the MS-PVD method for modification of the membrane's surface is a very promising perspective in the prevention of biofouling.

Construction of tunable “silica molecular brush” on the polyamide membrane surface for enhancing water permeability and antifouling performance

Surface modification has been widely applied for improvement permeability and antifouling performance of polyamide (PA) reverse osmosis (RO) membrane. A low-cost and easily obtained organoalkoxysilane, γ-Aminopropyl triethoxysilane (APTES), was grafted on PA RO membrane surface via a second interfacial polymerization (SIP) process combined with the activation effect of n-decane solvent, thus to form an antifouling PA surface with different silica brush-like structures, which can effectively weaken the attractive forces between the membrane surface and organic foulants. Meanwhile, n-decane solvent during the SIP process plays a dual function, which can not only minimize hydrolysis of both APTES monomers and unreacted acyl chloride groups on PA surface but also enhance microporosity of the nascent PA (solvent activation of PA), thereby grafting APTES on PA surface via amidation reaction can achieve maximization, and the water permeability of APTES modified PA (APTES-PA) membranes is improved. These APTES-PA membranes showed high water permeability (above 3.47 LMH/bar) with competitive NaCl rejection (above 98.75%), as well as excellent stability during 70 h of cross-flow test. Moreover, the existence of silica brush-like structures via grafting APTES molecules on PA layer can significantly elevate the antifouling performance of membranes against both negatively and positively charged foulants.

A nanofiltration membrane with positively and negatively charged groups by grafted p-aminosalicylic acid-Fe(III) chelation for Li+/Mg2+ efficient separation

High-performance nanofiltration (NF) membrane plays a key role in Li+/Mg2+ separation process. In this work, a new NF membrane with positively and negatively charged groups was prepared by grafting p-aminosalicylic acid (AS) onto the surface of polyamide (PA) membrane followed by chelation with Fe3+ ions for Li+/Mg2+ separation. The AS grafting (PA-g-AS) and Fe3+ chelating (PA-g-AS-Fe) NF membranes had almost same surface and section structure and surface pore size as the PA membrane. But Zeta potential (about −8 mV at pH 7) of the obtained PA-g-AS-Fe membrane was improved in comparison with the PA and PA-g-AS NF (about −20 mV at pH 7) membranes due to Fe3+ addition, suggesting that there were positively and negatively charged groups on the membrane surface. The PA-g-AS-Fe membrane showed a high Mg2+ rejection of 97.7% and high Li+ permeation (negative rejection of −87.6%); while a high Li+/Mg2+ separation factor (SLi,Mg) of about 81.5 was achieved, which is much higher than those for PA and PA-g-AS NF membranes and surpassed those of the results reported in literature. The fluxes of three membranes were about the same. The results demonstrated the NF membrane with positively and negatively charged groups was suitable for efficient separation of Li+/Mg2+ and would have promising applications in recovery of lithium from brine.

Functionalized polyamide membranes yield suppression of biofilm and planktonic bacteria while retaining flux and selectivity

• Ag-MOFs incorporated into the surface of FO polyamide membranes at 0.03–0.06% mass. • Wettability and surface charge characteristics were favorable for antifouling. • Forward osmosis operation demonstrated suitable water flux and low reverse salt flux. • Nearly complete suppression of P. aeruginosa biofilm and planktonic E. coli achieved. • Flux and selectivity retained during organic fouling and biofouling experiments. Biofouling is a major challenge for desalination, water treatment, and water reuse applications using polymer-based membranes. Two classes of novel silver-based metal azolate frameworks (MAF) are proposed to decorate polyamide (PA) forward osmosis membranes and to improve numerous aspects of fouling and transport. Membranes functionalized with two concentrations of each MAF are compared with a pristine control material, with results that clearly highlight their tunability and bio-inhibitory effects. We report for the first time PA membranes yielding near complete suppression of a robust biofilm-forming bacterium ( Pseudomonas aeruginosa ) and inactivation of planktonic bacteria, while maintaining high selectivity. These features improve the long-term water flux performance of the membranes, tested during 24 h of accelerated biofouling and organic fouling conditions, and showing lower than 10% and 20% decline in water flux. These enhancements were achieved with only 0.03–0.06% mass of additives and little generation of hazardous waste products, indicating that low-cost and environmentally benign functionalization can prevent biofouling growth while maintaining selectivity and transport for high-performance desalination, water treatment and reuse.

Construction of Tunable "Silica Molecular Brush" on the Polyamide Membrane Surface for Enhancing Water Permeability and Antifouling Performance

Construction of Tunable "Silica Molecular Brush" on the Polyamide Membrane Surface for Enhancing Water Permeability and Antifouling Performance

How alginate monomers contribute to organic fouling on polyamide membrane surfaces?

Organic fouling of polyamide membrane surfaces with alginate molecules in an aqueous solution is studied through computer molecular simulations. Here, we focus on the molecular binding properties of β-d-mannuronic acid (M) and α-l-guluronic acid (G) alginate monomers on a polyamide membrane surface. Free energy calculations show that M alginate monomers exhibit significant hydrophobic attractions with certain types of benzene ring units in a polyamide chain, though such hydrophobic interactions are not as strong as the ionic bridge binding between the M monomer and the carboxylate group on a polyamide membrane surface. This is in contrast to the fouling behavior of G alginate monomers to which such hydrophobic interactions with a membrane surface do not exist, and the organic fouling is largely attributed to the ionic bridge binding between the G monomer and polyamide carboxylate groups mediated by divalent metal ions. Molecular dynamics simulations of different alginate oligomers near a polyamide surface show that hydrophobic interactions between the M-containing oligomers and polyamide membrane surface result in a much shorter pathway of fouling than that of pure G-oligomers. These hydrophobic interactions, together with the mobility of M monomers on a polyamide chain surface, further reduce the docking time of M-containing oligomers compared to pure G-oligomers, and thus enhance the surface fouling.

Chlorine-resistant positively charged polyamide nanofiltration membranes for heavy metal ions removal

Heavy metal pollution is one of the most serious environmental problems. Nanofiltration (NF) is an effective and potential membrane separation technology for removal of heavy metal ions from water. However, the separation performance and chlorine resistance of NF membranes should be further improved in industry. Herein, to obtain exceptional water permeability and chlorine resistance, novel positively charged polyamide (PA-PDMC) NF membranes were fabricated by surface-initiated atom transfer radical polymerization (SI-ATRP), through which methacryloxyethyltrimethyl ammonium chloride (DMC) was grafted to the 2-bromoisobutyryl bromide (BIBB) exposed on the surface of polyamide (PA-Br1) membrane. The graft length of positively charged polymer chains were controlled by ATRP time, which furtherly exerted influences on the surface structures and properties of PA-PDMC membranes. At the optimal graft content, the retentions to MgCl2, CaCl2, CuCl2, ZnCl2 of the as-prepared PA-PDMC membrane were 92.8%, 90.8%, 93.5% and 96.8% respectively with the flux of 82.5 L m−2 h−1, which maintained stability during the long-term operation process of 168 h. Moreover, the PA-PDMC membrane exhibited exceptional chlorine resistance at the chlorination condition of 12,000 ppm h.

Thin-Film Composite Polyamide Membranes with In Situ Attached Ag Nanoparticles for Fouling-Mitigated Wastewater Treatment

As an ideal membrane for wastewater treatment, desirable separation performance, and fouling resistance are both requisite. Herein we directly in situ attached Ag based nanoparticles on the surface of thin-film composite polyamide (TFC PA) membranes by using benzenediamine (BDA) derivatives with acid functional groups as one aqueous monomer mixed with m-phenylenediamine (MPD) for interfacial polymerization (IP). The acid functional groups in BDA derivatives incorporated in the PA layer facilitated the in situ metallization or mineralization without grafting additional “bridge” linkers. Various characterization techniques were employed to elucidate the modification mechanism. The effects of molecular structures of BDA derivatives on the surface properties, separation performance, and antifouling capacity of resulting membranes were also systematically investigated. Compared with the pristine TFC membrane, the modified membranes exhibited the 85.83% water flux enhancement and 65.25% lower reverse salt flux overcoming the permeability-selectivity trade-off. Moreover, the total Ag loading of modified membranes increases by 8–14 times as compared to that of the pristine one, thereby the enhanced antibacterial and antifouling capacities in wastewater treatment.

A Dopamine/Tannic-Acid-Based Co-Deposition Combined with Phytic Acid Modification to Enhance the Anti-Fouling Property of RO Membrane.

Reverse osmosis (RO) membranes are widely used in the field of water treatment. However, there are inevitably various fouling problems during long-term use. Surface engineering of RO membranes, such as hydrophilic modification, has attracted broad attention for improving the anti-fouling performance. In this work, we constructed a green biomimetic composite modification layer on the surface of polyamide membranes using a dopamine (DA)/tannic acid (TA) co-deposited layer to bridge the polyamide surface and hydrophilic phytic acids (PhA). The DA/TA interlayer could firmly adhere to the RO membranes, reducing the aggregation of DA and providing abundant phenolic hydroxyl sites to graft PhA. Meanwhile, the anchored PhA molecule bearing six phosphate groups could effectively improve the superficial hydrophilicity. The membranes were characterized by the SEM, AFM, XPS, water contact angle test, and zeta potential test. After surface modification, the hydrophilicity, smoothness, and surface electronegativity were enhanced obviously. The flux and rejection of the virgin membrane were 76.05 L·m−2·h−1 and 97.32%, respectively. While the modified D2/T4-PhA membrane showed decent permeability with a water flux of 57.37 L·m−2·h−1 and a salt rejection of 98.29%. In the dynamic fouling test, the modified RO membranes demonstrated enhanced anti-fouling performance toward serum albumins (BSA), sodium alginates (SA), and dodecyl trimethyl ammonium bromides (DTAB). In addition, the modified membrane showed excellent stability in the 40 h long-term test.

Facile Surface Modification of Polyamide Membranes Using UV-Photooxidation Improves Permeability and Reduces Natural Organic Matter Fouling.

A new optimized ultraviolet (UV) technique induced a photooxidation surface modification on thin-film composite (TFC) polyamide (PA) brackish water reverse osmosis (BWRO) membranes that improved membrane performance (i.e., permeability and organic fouling propensity). Commercial PA membranes were irradiated with UV-B light (285 nm), and the changes in the membrane performance were assessed through dead-end and cross-flow tests. UV-B irradiation at 12 J·cm-2 enhanced the pure water permeability by 34% in the dead-end tests without decreasing the mono- or divalent ion rejections, as compared with the pristine PA membrane, and led to less fouling by natural organic matter in the cross-flow tests. Scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) confirmed that UV-B irradiation opened the pore structure and created carboxylic and amine groups on the PA surface, leading to increased membrane surface charge and hydrophilicity. Thus, an optimal UV-B dose appears to modify only a thin layer of the PA membrane surface, which favorably enhances the membrane performance. UV-B did not alter the structure, flux, or salt rejection for cellulose triacetate (CTA)-based membranes. While other membrane surface modifications include oxidants, strong acids, and bases, the UV-B facile treatment is chemical-free, thus reducing chemical wastes, and easy to apply in roll-to-roll fabrication processes of PA membranes. The results also showed that a low UV irradiation dose could be applied to PA or CTA membranes for disinfection or photocatalytic oxidation.

Mussel-inspired surface functionalization of polyamide microfiltration membrane with zwitterionic silver nanoparticles for efficient anti-biofouling water disinfection

Mature microfiltration (MF) membrane is a low-cost, effective, and promising technology to provide affordable purified water for people living in developing countries. However, the lack of disinfection ability and inherent membrane fouling problems have seriously restricted the large-scale application of conventional MF treatment system in producing safe drinking water. In this work, zwitterionic silver nanoparticles (AgNPs) with surface modification of poly(carboxybetaine acrylate-co-dopamine methacryamide) (PCBDA) copolymers were robustly immobilized onto commercial polyamide MF membrane via mussel-inspired chemistry for water disinfection. The designed microfiltration membrane, named as PCBDA@AgNPs-MF, exhibited integrated properties of high and stable payload of AgNPs, broad-spectrum anti-adhesive and antimicrobial activities, and easy removal of inactivated microbial cells from membrane surface. Ascribing to the synergetic effect of anti-adhesive and antimicrobial features brought by zwitterionic PCBDA@AgNPs, the biofilms growth on polyamide membrane surface was significantly inhibited, which showed potential access to achieve long-term biofouling resistance and maintain water flux for conventional MF membrane. As water disinfection device, these attributes enabled PCBDA@AgNPs-MF to effectively disinfect the model and natural bacteria-contaminated water.

Effects of surfactants and oil-in-water emulsions on reverse osmosis membrane performance

Oily wastewater from various industries is a major source of pollution. Membrane-based separation is a promising technique for treating oil-in-water emulsions. However, membrane fouling remains a crucial drawback for wide application of membrane separation in oily wastewater treatment. This study was performed to gain a better understanding of the fouling of two commercial reverse osmosis membranes by oil-in-water emulsions. Cellulose acetate (CA) and polyamide (PA) reverse osmosis (RO) membranes were used in the separation of olive oil-in-water emulsions stabilized by nonionic, cationic, and anionic surfactants in a dead-end separation configuration. Both membranes exhibited high total organic carbon (TOC) rejection. Analysis of the results indicated that the permeate flux from the cellulose acetate membrane did not depend on the surfactant type or oil concentration present, whereas the permeate flux from the polyamide membrane was influenced by the type of surfactant used in the oil-in-water emulsion. It appears that the surfactant was adsorbed onto the polyamide membrane surface due to electrostatic and hydrophilic/hydrophobic interactions. The results of this study provide useful insights into membrane fouling during emulsion separation. The CA membrane exhibited less fouling than the PA membrane, making it a better candidate for oily wastewater treatment. The PA membrane was more effective at treating the emulsion stabilized by an anionic surfactant. Determining the feed composition and membrane properties before separation allows better fouling control, thus reducing treatment costs.

A biomimetic antimicrobial surface for membrane fouling control in reverse osmosis for seawater desalination

Membrane fouling occurs in all membrane processes. Surface modifications have gained popularity for enhancing membrane antifouling capability via introducing a hydrophilic component or reducing membrane surface roughness. In this work, we proposed to develop a green antimicrobial lysozyme nanofilm on the polyamide membrane surface with remarkable antibacterial and antifouling properties to effectively reduce membrane fouling. The nanofilm is rooted in the molecular assembly of a protein which is an extraction of food and natural products. The nanofilm exhibits the combination of various functions including antimicrobial, antifouling and antibiofilm. This protein-based nanofilm is robustly transferred and self-adhered on the membrane surface by a simple one-step aqueous coating. The modified RO membrane exhibited good performance in bacterial reduction of ~50% in comparison to the control membrane and experienced almost zero loss in water flux and salt rejection under SWRO testing condition. The membrane is further evaluated with real seawater for 14 days and the modified membrane showed its superiority in flux and fouling control which were verified by the confocal laser scanning microscopy (CLSM) and quantified by inductively coupled plasma optical emission spectrometer (ICP-OES). This work demonstrates that the protein-based biomaterials offer a safe and environmentally friendly way of antimicrobials, which can reduce membrane fouling significantly in membrane filtration.

Improvement of Hydrophilicity for Polyamide Composite Membrane by Incorporation of Graphene Oxide-Titanium Dioxide Nanoparticles.

In this work, the polyamide (PA) membrane surface has been modified by coating of nanomaterials including graphene oxide (GO) and titanium dioxide (TiO2) to enhance membrane separation and antifouling properties. The influence of surface modification conditions on membrane characteristics has been investigated and compared with a base membrane. Membrane surface properties were determined through scanning electron microscope (SEM) images and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Membrane separation performance was determined through the possibility for the removal of methylene blue (MB) in water. Membrane antifouling property was evaluated by the maintained flux ratios (%) after 120 minutes of filtration. The experimental results showed that the appearance of hydrophilic groups after coating of GO and TiO2 nanocomposite materials with or without UV irradiation onto membrane surface made an improvement in the separation property of the coated membranes. The membrane flux increased from 28% to 61%; meanwhile, the antifouling property of the coated membranes was improved clearly, especially for UV-irradiated PA/GO-TiO2 membrane.

Enhanced efficiency of polyamide membranes by incorporating TiO2-Graphene oxide for water purification

Membrane-based separation processes are very effective in several applications such as purification of drinking water and treatment of wastewater. Polymer-inorganic composite reverse osmosis membrane is a powerful method that opens the door to merge different properties of inorganic materials like mechanical and thermal stability with organic polymer properties including processability and flexibility. This work aims to modify aromatic polyamide membrane surfaces by the simultaneous incorporation of graphene oxide (GO) and TiO2 composite, to enhance the salt rejection and filtration performance of the membrane. 1, 3, 5-benzenetricarbonyl chloride, TiO2-GO composite, and m-phenylenediamine were polymerized on the surface of porous polysulfone support. Fourier Transform infra-red spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were applied to confirm the presence of TiO2-GO composite on the membrane surface. Scanning electron microscopy equipped with energy-dispersive X-ray and atomic force microscopy were carried out to analyze the surface morphology and reveal the smoothening of the modified membrane surface. Water contact angle measurements were carried out to visualize the hydrophilicity improvements of modified membranes. The performance parameters of the membrane, including permeate flux, salt rejection, and oil rejection were evaluated using a laboratory setup. The incorporation of TiO2-GO composite into the membrane matrix enhanced the membrane performance with 62 LMH (Lm−2h−1) permeate flux, 97% salt rejection, and 100% hydrocarbons rejection, due to changes in charge, roughness, and hydrophilicity of the membrane surface.

Atomistic Simulations of Biofouling and Molecular Transfer of a Cross-linked Aromatic Polyamide Membrane for Desalination.

Reverse osmosis through a polyamide (PA) membrane is an important technique for water desalination and purification. In this study, molecular dynamics simulations were performed to study the biofouling mechanism (i.e., protein adsorption) and nonequilibrium steady-state water transfer of a cross-linked PA membrane. Our results demonstrated that the PA membrane surface's roughness is a key factor of surface's biofouling, as the lysozyme protein adsorbed on the surface's cavity site displays extremely low surface diffusivity, blocking water passage, and decreasing water flux. The adsorbed protein undergoes secondary structural changes, particularly in the pressure-driven flowing conditions, leading to strong protein-surface interactions. Our simulations were able to present water permeation close to the experimental conditions with a pressure difference as low as 5 MPa, while all the electrolytes, which are tightly surrounded by hydration water, were effectively rejected at the membrane surfaces. The analysis of the self-intermediate scattering function demonstrates that the dynamics of water molecules coordinated with hydrogen bonds is faster inside the pores than during the translation across the pores. The pressure difference applied shows a negligible effect on the water structure and content inside the membrane but facilitates the transportation of hydrogen-bonded water molecules through the membrane's sub-nanopores with a reduced coordination number. The linear relationship between the water flux and the pressure difference demonstrates the applicability of continuum hydrodynamic principles and thus the stability of the membrane structure.