Polyamide Active Layer Research Articles

Two-dimensional fractal nanocrystals templating for substantial performance enhancement of polyamide nanofiltration membrane.

In this study, we report the emergence of two-dimensional (2D) branching fractal structures (BFS) in the nanoconfinement between the active and the support layer of a thin-film-composite polyamide (TFC-PA) nanofiltration membrane. These BFS are crystal dendrites of NaCl formed when salts are either added to the piperazine solution during the interfacial polymerization process or introduced to the nascently formed TFC-PA membrane before drying. The NaCl dosing concentration and the curing temperature have an impact on the size of the BFS but not on the fractal dimension (∼1.76). The BFS can be removed from the TFC-PA membranes by simply dissolving the crystal dendrites in deionized water, and the resulting TFC-PA membranes have substantially higher water fluxes (three- to fourfold) without compromised solute rejection. The flux enhancement is believed to be attributable to the distributed reduction in physical binding between the PA active layer and the support layer, caused by the exertion of crystallization pressure when the BFS formed. This reduced physical binding leads to an increase in the effective area for water transport, which, in turn, results in higher water flux. The BFS-templating method, which includes the interesting characteristics of 2D crystal dendrites, represents a facile, low-cost, and highly practical method of enhancing the performance of the TFC-PA nanofiltration membrane without having to alter the existing infrastructure of membrane fabrication.

Polyamide Nanofiltration Membranes from Surfactant‐Assembly Regulated Interfacial Polymerization: The Effect of Alkyl Chain

AbstractRegulating the monomer diffusion during interfacial polymerization (IP) process is the key for tailoring the pore structure and desalination performance of thin‐film composite polyamide nanofiltration (NF) membrane. Recently a surfactant‐assembly strategy to regulate IP process and NF membranes with sub‐Å separation precision is proposed. However, little is known for the role of the molecular structure of surfactant on IP process and membrane performance. In this work, five sulfate surfactants with different length of alkyl chains are used to construct surfactant monolayer assembly at the water/hexane interface to regulate IP process. The results show that for the sulfate surfactants, the longer the alkyl chain, the more uniform the pore size distribution of polyamide active layer is and the higher the ion separation selectivity of NF membrane is. Among them, the NF membrane prepared from sodium n‐hexadecyl sulfate (SHS) exhibits the highest separation performance with the rejection of Na2SO4, MgSO4, MgCl2, and CaCl2 up to 99.39%, 99.12%, 98.09%, and 97.38%, respectively. Overall, this study further confirms the regulatory role of surfactant‐assembled monolayer during IP process and provides important insights into how the polyamide structure and the resulting NF membranes are influenced by the alkyl chain length of the surfactants.

Electrospun nanofiber based forward osmosis membrane using graphene oxide as substrate modifier for enhanced water flux and rejection performance

Electrospun nanofiber (ENs) membranes with advantages of high porosity and low tortuosity have been considered as the ideal forward osmosis (FO) substrates for the effective mitigation of internal concentration polarization (ICP). However, the rough surface and large surface pores of ENs substrates may have adverse effects on the properties of the polyamide (PA) active layer. In this study, graphene oxide (GO) nanosheet was chosen as the modifier to adjust the characteristics of polyacrylonitrile (PAN) ENs substrate. The structure and properties (e.g., osmotic flux and specific salt flux) of the PA active layer was found be effectively tailored by the GO loading density. The appropriate loading of GO nanosheets might retard the penetration of polyamide into the substrate surface pores and meanwhile enhance the cross-linking degree of the PA active layer, resulting in the improvement of water flux and salt rejection. The optimized FO membrane (TFC-GO2) could achieve a higher water flux (32.7 g/m2·h) and lower specific salt flux (0.26 g/L) than the control membrane (TFC-0) in the FO mode. The appropriate loading of GO nanosheets on ENs substrates was proven to be a competitive strategy for developing high-performance ENs based FO membranes.

Desalination membranes by deposition of polyamide on polyvinylidene fluoride supports using the automated layer-by-layer technique

ABSTRACT Thin-film composite (TFC) membranes with a polyamide (PA) active layer are the industry standard in desalination applications. The layer-by-layer (LbL) approach provides more precise control over the properties of this active PA layer. The automated spin-assisted LbL version of this approach then minimizes human error and improves repeatability. To improve durability of these membranes, more robust supports are desired, such as polyvinylidene fluoride (PVDF). The use of the LbL technique on this support requires an interlayer to enable the deposition onto the PVDF. In this case, levodopa was utilized to coat the PVDF prior to deposition of the PA layer. The membranes exhibited moderate permeability and higher selectivity for sodium chloride under typical brackish water conditions compared to commercially available NF membranes. This novel interlayer further expands on the automated spin assisted LbL approach, enabling deposition of PA onto a support.

High‐flux and solvent‐selective membranes with aromatic functionalities and dual‐layer structures

AbstractEfficient separation of aromatic‐aliphatic hydrocarbon mixtures has long been an important topic in chemical industries. Organic nanofiltration (OSN) has been revealing great promise in separating solvent mixtures that has not been effectively resolved by the state‐of‐the‐art technologies. Herein, novel OSN membranes are designed for the separation of toluene and n‐heptane. Polyamide active layer with diaminonaphthalene as the aqueous phase monomer is prepared by interfacial polymerization for the first time. The addition of polydimethylsiloxane gutter layer, as well as the combination of spin coating technique and macroporous substrate, renders the membranes with loose and defect‐free architectures. The as‐designed membranes achieve a rather high selectivity of toluene over n‐heptane (>4) together with ultra‐high toluene permeance (>180 L m−2 h−1 bar−1). These membranes also present excellent stability in the long‐term operation.

High-performance thin-film nanocomposite (TFN) forward osmosis (FO) membranes incorporated with porous hydrophobic-core/hydrophilic-shell nanoparticles

The current article discusses some unprecedented information about the improvement in forward osmosis (FO) performance of polyethersulfone/polyamide (PES/PA) membranes, mainly focused on water flux and selectivity along with resistance to fouling phenomenon; which itself is brought in by the introduction of pre-modified zeolitic imidazolate framework-8 MOF nanoparticles. An investigation has been conducted on ZIF-8 nanoparticles surface with hydrophilicity feature to evaluate their potential for utilization in active polyamide layer of FO membranes for the first time, free from any decrease in water flux value (when hydrophobic ZIF-8 is exploited solely) and selectivity (when mSiO2 with unselective channels is employed). Correspondingly, to fulfill the desired goal, MOF nanocrystals were coated with a thin mSiO2 shell at first, so they can be modified in the next step by GPTMS and ultimately aspartic acid. Feasibility of applied strategy (using hydrophobic-core/hydrophile-shell nanofillers) in FO membranes' desalination performance was assessed after incorporating ZIF-8@mSiO2-GPTMS-Asp nanoparticles of various concentrations in the polyamide rejection layer throughout the interfacial polymerization (IP) process. The obtained results divulge that the optimal membrane (TFN400) has the highest water flux and selectivity as well as superior resistance to BSA and SA foulant.

Feasibility of H2O2 cleaning for forward osmosis membrane treating landfill leachate

This study reports landfill leachate treatment by the forward osmosis (FO) process using hydrogen peroxide (H2O2) for membrane cleaning. Although chemical cleaning is an effective method for fouling control, it could compromise membrane integrity. Thus, understanding the impact of chemical cleaning on the forward osmosis membrane is essential to improving the membrane performance and lifespan. Preliminary results revealed a flux recovery of 98% in the AL-FS mode (active layer facing feed solution) and 90% in the AL-DS (draw solution faces active layer) using 30% H2O2 solution diluted to 3% by pure water. The experimental work investigated the effects of chemical cleaning on the polyamide active and polysulfone support layers since the FO membrane could operate in both orientations. Results revealed that polysulfone support layer was more sensitive to H2O2 damage than the polyamide active at a neutral pH. The extended exposure of thin-film composite (TFC) FO membrane to H2O2 was investigated, and the active layer tolerated H2O2 for 72 h, and the support layer for only 40 h. Extended operation of the TFC FO membrane in the AL-FS based on a combination of physical (hydraulic flushing with DI water) and H2O2 was reported, and chemical cleaning with H2O2 could still recover 92% of the flux.

Thin-Film Nanocomposite Membrane Incorporated with Porous Zn-Based Metal-Organic Frameworks: Toward Enhancement of Desalination Performance and Chlorine Resistance.

Metal-organic framework (MOF) materials have received extensive attention for the design of advanced thin-film nanocomposite (TFN) membranes with excellent permselectivity. However, the relationship between the unique physicochemical properties and performance of engineered MOF-based membranes has yet to be extensively investigated. In this work, we investigate the incorporation of porous zinc-based MOFs (Zn-MOFs) into a polyamide active layer for the fabrication of TFN membranes on porous poly(phenylsulfone) (PPSU) support layers through an interfacial polymerization approach. The actual effects of varying the amount of Zn-MOF added as a nanofiller on the physicochemical properties and desalination performance of TFN membranes are studied. The presence and layout of Zn-MOFs on the top layer of the membranes were confirmed by X-ray photoelectron spectroscopy, scanning electron microscopy, and ζ potential analysis. The characterization results revealed that Zn-MOFs strongly bind with polyamide and significantly change the membrane chemistry and morphology. The results indicate that all four studied TFN membranes with incorporated Zn-MOFs enhanced the water permeability while retaining high salt rejection compared to a thin-film composite membrane. Moreover, the highest-performing membrane (50 mg/L Zn-MOF added nanofiller) not only exhibited a water permeability of 2.46 ± 0.12 LMH/bar but also maintained selectivity to reject NaCl (>90%) and Na2SO4 (>95%), similar to benchmark values. Furthermore, the membranes showed outstanding water stability throughout 72 h filtration and chlorine resistance after a 264 h chlorine-soaking test because of the better compatibility between the polyamide and Zn-MOF nanofiller. Therefore, the developed TFN membrane has potential to solve trade-off difficulties between permeability and selectivity. Our findings indicate that porous Zn-MOFs play a significant role in the development of a TFN membrane with high desalination performance and chlorine resistance.

Nanofiltration membrane combining environmental-friendly polycarboxylic interlayer prepared from catechol for enhanced desalination performance

The strategy of introducing a hydrophilic interlayer on the porous substrate has been widely applied in the modification of nanofiltration (NF) membranes. Herein, an environmentally friendly polycarboxylic interlayer is prepared from the mixture of catechol and sodium periodate (SP). Catechol is easy to oxidize to generate reactive o-quinones which undergoes phenolic polymerization to form covalent polymer with the carboxyl group, with the effect of SP initiation. Due to the introduction of carboxylic group, the interlayer is hydrophilic and can store more piperazine molecules to provide a more uniform platform for interfacial polymerization, which is conductive to form a thin and dense polyamide (PA) active layer. Compared with the traditional membrane, the modified thin film composite (TFC) membrane exhibits 1.7-fold of permeance (up to 15.4 ± 1 L·m−2·h−1 bar−1), maintaining a high rejection of Na2SO4 (98.42 ± 1.2%). Although the TFC membrane without an interlayer tends to be thick and defective in low PIP concentration, the role of the interlayer can eliminate this limitation. Besides, the modified TFC membrane possesses a high electronegativity with the fact that isoelectric point (3.29) has been lower than that of the traditional membrane, which has the potential to separate negative organic pollutants in the wastewater treatment.

Sustainable Cellulose Nanocrystals for Improved Antimicrobial Properties of Thin Film Composite Membranes

In this study, we were able to impart antimicrobial properties onto the surface of a commercial thin-film composite (TFC) membrane using sustainably derived cellulose nanocrystals (CNC) extracted from elephant grass (Pennisetum purpureum) leaves. Carboxylic acid-containing CNC were chemically bound to the amine-terminated polyamide active layer of TFC membranes using a cross-linking reaction. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy were conducted to confirm the presence of CNC on the membrane surface. TFC membranes functionalized with needle-like and antimicrobial CNC nanoparticles showed robust toxicity to bacteria, inactivating ∼89% of attached Escherichia coli cells under contact. These findings establish that functionalization with CNC is a promising approach for mitigating biofouling on TFC membranes and substantiates the application of sustainable materials for the design of the next-generation membranes for water purification.

Nanofiltration‐like forward osmosis membranes on in‐situ mussel‐modified polyvinylidene fluoride porous substrate for efficient salt/dye separation

AbstractHere, polyvinylidene fluoride (PVDF) membranes were fabricated via non‐solvent induced phase separation (NIPS) using dopamine (DA) and polyethyleneimine (PEI) as the hydrophilic additives, which has a loose surface and somewhat improved hydrophilicity. Then nanofiltration (NF)‐like thin‐film composite forward osmosis (TFC FO) membrane with a loose polyamide (PA) active layer on the blend membrane was synthesized via the interfacial polymerization. The as‐prepared NF‐like TFC FO membrane exhibited a high water flux (Jw) of 29.98 L m−2 h−1 and a much low specific salt flux (Js/Jw) of 0.018 g/L, when 0.6 M NaCl was used as draw solution (DS). It had a superior rejection of malachite green (99.6% ± 0.1%) and a low rejection of NaCl (27.4% ± 4.2%), when filtrated malachite green/NaCl mixture solution in active layer‐facing draw solution (AL‐FS) mode. The results provide new insights on the design and preparation of FO membranes of selective separation for dyes from salty water.

Alleviation of Reverse Salt Leakage across Nanofiber Supported Thin-Film Composite Forward Osmosis Membrane via Heat-Curing in Hot Water.

Electrospun nanofiber with interconnected porous structure has been studied as a promising support layer of polyamide (PA) thin-film composite (TFC) forward osmosis (FO) membrane. However, its rough surface with irregular pores is prone to the formation of a defective PA active layer after interfacial polymerization, which shows high reverse salt leakage in FO desalination. Heat-curing is beneficial for crosslinking and stabilization of the PA layer. In this work, a nanofiber-supported PA TFC membrane was conceived to be cured on a hot water surface with preserved phase interface for potential “defect repair”, which could be realized by supplementary interfacial polymerization of residual monomers during heat-curing. The resultant hot-water-curing FO membrane with a more uniform superhydrophilic and highly crosslinked PA layer exhibited much lower reverse salt flux (FO: 0.3 gMH, PRO: 0.8 gMH) than that of oven-curing FO membrane (FO: 2.3 gMH, PRO: 2.2 gMH) and achieved ∼4 times higher separation efficiency. It showed superior stability owing to mitigated reverse salt leakage and osmotic pressure loss, with its water flux decline lower than a quarter that of the oven-curing membrane. This study could provide new insight into the fine-tuning of nanofiber-supported TFC FO membrane for high-quality desalination via a proper selection of heat-curing methods.

Enhanced Water Permeability and Antifouling Property of Coffee-Ring-Textured Polyamide Membranes by In Situ Incorporation of a Zwitterionic Metal-Organic Framework.

Modulation of the polyamide structure is critically important for the reverse-osmosis performance of thin-film composite (TFC) membranes in the field of water reuse and desalination. Herein, zwitterionic nanoparticles of zeolitic imidazolate framework-8 (PZ@ZIF-8) were fabricated and incorporated into the polyamide active layer through the interfacial polymerization method. A hydrophilic, zwitterionic coffee-ring structure was formed on the surface of polyamide thin-film nanocomposite (TFN) membranes due to the adjusted diffusion rate of m-phenylenediamine (MPD) from the aqueous phase into the organic phase during the interfacial polymerization process. Surface characterization demonstrated that the coffee-ring structure increased the amounts of water transport channels on the membrane surface and the intrinsic pores of PZ@ZIF-8 maintained the salt rejection. Antifouling and bactericidal activities of TFN membranes were enhanced remarkably owing to the bacterial-"defending" and bacterial-"attacking" behaviors of hydrophilic and zwitterionic groups from PZ@ZIF-8 nanoparticles. This work would provide a promising method for the application of MOFs to enhance the bio-/organic-fouling resistance of TFN membranes with high water permeation and salt rejection.

Synthesis of Novel Hybrid NF/FO Nanocomposite Membrane by Incorporating Black TiO2 Nanoparticles for Highly Efficient Heavy Metals Removal

In this study, a hybrid of nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving the efficiency of heavy metal removal. Here, black TiO2 nanoparticles (BNPs) were synthesized first and embedded in the polyamide (PA) active layer of TFC NF membrane to rectify the performance of membranes. The resulting TFN NF membranes were then tested in hybrid NF/FO system properly. The presence of BNPs was confirmed with XPS and FTIR, while the morphological alterations in the synthetized membranes were characterized using FESEM and AFM. Nanofiltration membrane performance was examined using multivalent ions such as of MgSO4, Na2SO4, CaCl2, and NaCl monovalent ion. We demonstrated that the addition of BNPs led to a significant decrease in surface roughness and hydrophilicity, showing a further reduction with increased concentrations of BNPs. In addition, TFC membrane showed a water flux of 25 L/m2h compared to 39, 41, and 66 L/m2h for TFN0.01, TFN0.05, and TFN0.1 membranes, respectively. We also showed that under the FO process, TFN membrane demonstrated the best performance with regards to heavy metal rejection and the highest Cr (III) and Pb (II) rejection was shown in TFN0.05 under the FO process. The ideal heavy metal rejections and acceptable water flux indicate the potential of these developed membranes under FO process for the removal of heavy metals from wastewater.

Channel regulation of TFC membrane with hydrophobic carbon dots in forward osmosis

Zero-dimensional carbon dots have emerged as important nanofillers for the separation membrane due to their small specific size and rich surface functional groups. This study proposed a strategy based on hydrophobic carbon dots (HCDs) to regulate water channels for an efficient forward osmosis (FO) membrane. Thin-film composite (TFC) membranes with superior FO performance are fabricated by introducing HCDs as the nanofiller in the polyacrylonitrile support layer. The introduction of HCDs promotes the formation of the support layer with coherent finger-like hierarchical channels and micro-convex structure and an integrated polyamide active layer. Compared to the original membrane, TFC-FO membrane with 10 wt% HCDs exhibits high water flux (15.47 L m−2 h−1) and low reverse salt flux (2.9 g m−2 h−1) using 1 mol/L NaCl as the draw solution. This improved FO performance is attributed to the lower structural parameters of HCDs-induced water channels and alleviated internal concentration polarization. Thus, this paper provides a feasible strategy to design the membrane structure and boost FO performance.

Effect of Feed Water pH on the Partitioning of Alkali Metal Salts from Aqueous Phase into the Polyamide Active Layers of Reverse Osmosis Membranes.

The partitioning of solutes into the polyamide active layers of reverse osmosis (RO) membranes is a key membrane property determining solute permeation. Quantification of partition coefficients and their dependence on feedwater pH would contribute to the development of predictive transport models of contaminant transport through RO membranes; however, neither solute partitioning nor the effect of feed solution pH on partitioning has been thoroughly characterized in the literature. Accordingly, we characterized the partitioning of all chloride salts of alkali metals (CsCl, RbCl, KCl, NaCl, and LiCl) from the aqueous phase into the polyamide active layers of five polyamide RO membranes, including one prepared in-house and four commercial membranes. We evaluated the effect of pH on the partitioning of alkali metal salts and whether the effect of pH on salt partitioning and rejection is consistent with Donnan theory predictions. Results showed that for all membranes, the partition coefficients of all salts were less than one and did not differ substantially among RO membranes. Results also indicated that for all membranes tested, Donnan theory provided an appropriate theoretical framework to estimate the effect of pH on salt partitioning (evaluated for all chloride salts of alkali metals) and salt rejection (evaluated for NaCl). Thus, we conclude that changes in salt rejection resulting from feed solution pH are primarily driven by changes in salt partitioning with comparatively small changes in salt diffusion coefficients.

Polyamide membrane with an ultrathin GO interlayer on macroporous substrate for minimizing internal concentration polarization in forward osmosis

The conventional polyamide membranes composed of a polyamide active layer on an ultrafiltration (UF) substrate hold a dominant position in forward osmosis (FO). However, the membrane permeation is currently restricted by severe internal concentration polarization (ICP) due to the high resistance of the UF substrate with hierarchical pore structures. Herein, an ultrathin graphene oxide (GO) interlayer on polyethersulfone (PES) macroporous substrate is intentionally constructed to tailor the structure of composite membrane, and thus improve the separation performance. The ultrathin GO interlayer not only inhibits the penetration of polyamide into substrate, but also provides a smooth surface for interfacial polymerization (IP). Besides, it can significantly decrease membrane resistance due to its thickness of only 10 nm. Consequently, a uniform, continuous and defect-free polyamide active layer was formed due to the confined IP reaction upon the PES substrate. It was found that the polyamide membrane with GO interlayer exhibited a favorable water flux of 22 L m−2 h−1 at AL-FS mode with deionized water and 2 mol/L NaCl as feed and draw solutions, respectively, 144% higher than that of the control membrane without GO interlayer. Meanwhile, it achieved a moderate ICP over GO interlayer modified macroporous support. Moreover, it exhibited an excellent stability during 120 h test. The research provides a promising approach to fabricate high-performance polyamide membrane on macroporous substrate for forward osmosis.

Zr-Porphyrin Metal–Organic Framework-Based Photocatalytic Self-Cleaning Membranes for Efficient Dye Removal

The self-cleaning ability and reusability of a membrane are critical in practical applications because they can severely affect the lifespan and the separation efficiency of the membranes. In this work, hydrophilic Zr-porphyrin metal–organic frameworks (MOFs) with different dimensions (2D or 3D) were embedded in the polyamide active layer to develop a self-cleaning membrane with enhanced separation performance. Zr-porphyrin MOF (3D) with excellent photocatalytic activity and uniform 1D open triangular channels can not only endow this membrane with visible-light photocatalytic ability for the degradation of organic dyes deposited on the membrane surface but also provide additional transport channels leading to a high membrane permeate flux. The optimum membrane exhibits a superior water permeate flux of 110.4 L m–² h–¹ (threefold higher than the pristine thin-film composite membrane) while maintaining very high dye rejection (close to 100%) for five dyes (anionic dyes: Congo red, Direct red 23, and Reactive Black 5 and cationic dyes: methylene blue and rhodamine B) and an outstanding photocatalytic degradation self-cleaning ability (the recovery of water permeate flux exceeds 97% after 4 cycles). Overall, this study may offer new inspiration for designing and tuning Zr-porphyrin MOF-based self-cleaning membranes with excellent dye removal ability.

High Flux and Antifouling Thin-Film Nanocomposite Forward Osmosis Membrane with Ingrained Silica Nanoparticles

A novel high flux and antifouling thin-film nanocomposite (TFnC) forward osmosis (FO) membrane containing silica (SiO2) nanoparticles was fabricated using a facile electrospinning technique followed by interfacial polymerization on the surface of an electrospun nanofiber mat. Both the electrospun nylon-6 (N6) substrate and the polyamide (PA) active layer contained superhydrophilic SiO2 nanoparticles enhancing the hydrophilicity of the fabricated FO membrane. The electrospun N6/SiO2-supported TFnC FO membrane with a PA/SiO2 composite active layer was robust (tensile strength of 24.1 MPa) with a water contact angle of 14°. The membrane exhibited a high water flux (27.1 LMH) with a low specific reverse salt flux (5.9 × 10–3 mol L–1) at draw solution concentration of 1 M NaCl at 24 °C. The fabricated membrane also showed antifouling propensities for model foulants of sodium alginate and calcium sulfate. After fouling and cleaning operations, the flux recoveries were 98% and 94% (of the initial water flux) for the membranes fouled with sodium alginate and calcium sulfate, respectively. Moreover, a strong interaction between the active layer and the substrate highlighted the structural stability of the fabricated TFnC membrane.

Effect of different inorganic draw solutes on SiNPs-TFN membrane for forward osmosis desalination

Forward osmosis (FO) is the most promising upcoming desalination technique which requires more detailed researches to reduce its challenges like low pure water flux and high reverse solute flux. This paper represents the fabrication of thin-film nanocomposite polyethersulfone membrane with 0.005 wt% of silica nanoparticle (SiNPs) loading and analysis of FO performance of the fabricated TFN membrane. The nanoparticle was incorporated into the polyamide active rejection layer by interfacial polymerization. Membrane characterizations like ATR-FTIR, SEM, and wettability analysis were done. Successful nanoparticle incorporation was confirmed by ATR-FTIR analysis. Rise in hydrophilicity of TFN membrane was confirmed surface wettability measurements. The effect on draw solution concentration as well as cross-flow rate on membrane performance was analyzed. Comparison of forward osmosis performance with various inorganic draw solutes was also tested. The draw solutes considered were KCl, NaCl, and CaCl2 due to its various applications in fertigation and desalination. The filtration parameters of the fabricated membranes are analyzed and enlisted. The membrane FO performance under AL-FS and AL-DS modes of operation was tested. Results show that fabricated TFN membrane obtains a maximum flux of 23.93LMH in AL-DS mode, and salt rejection was 91%.