Improved Chlorine Resistance Research Articles

Effect of antibiotics and antibiotic by-products on the chlorine resistance of biofilms in drinking water distribution systems

This study investigated the effects of tetracycline (TC) and sulfadiazine (SD), along with their degradation products, on biofilm chlorine resistance. The results showed that low concentrations of antibiotics and their degradation products promoted biofilm formation on tube surfaces and increased resistance to chlorine. There was a positive correlation between antibiotic levels, degradation products, and biofilm chlorine resistance within a specific concentration range. SD had a more significant impact on biofilm chlorine resistance compared to TC. The presence of both antibiotics and their degradation products in water led to an increase in biofilm chlorine resistance, especially when combined with 0.3 mg/L sodium hypochlorite. The study shows a positive association between antibiotic and degradation product concentrations and the biofilms' improved chlorine resistance, a phenomenon that could have major consequences for water treatment efforts. Additionally, higher concentrations of antibiotics and their degradation products were associated with reduced biodiversity within the biofilm. Overall, the findings suggest that the presence of antibiotics and their degradation products can influence biofilm formation, alter bacterial species composition, and enhance biofilm resistance to chlorine in drinking water distribution systems. This fresh perspective on the relationship between pharmaceutical residues and microbial communities in water systems could transform our approach to assuring water safety and combatting antimicrobial resistance.

Hydrophilicity and surface charge modulation of Ti3C2T x MXene based membranes for water desalination.

Lamellar membranes obtained by stacking 2D layers possess ample transport pathways due to their intricate network of interlayer gaps. This makes them suitable for molecular separation applications. However, controlling the surface chemistry of the nanochannels within the membrane to tune the desired transport properties of water and ions is challenging. Ti3C2T x has been considered for water desalination because of its hydrophilic surface and negative surface charge. Most of the studies of Ti3C2T x membranes have presented promising salt rejection values in forward osmosis mode, which is less practical for water purification. Here, we investigate two types of reverse osmosis MXene-based lamellar membranes consisting of Ti3C2T x nanosheets hybridized with (i) WS2 nanosheets and (ii) polyvinyl phosphonic acid (PVPA). When hydrophilic and flexible Ti3C2T x nanosheets are interleaved with softer and more hydrophobic WS2 nanosheets in 2 : 1 mass ratio, nano capillaries with Janus chemistry are created with comparable rejection to bare Ti3C2T x membrane and threefold higher permeance values. Further, we find that decorating Ti3C2T x nanosheets with anionic polymers improves salt rejection. Our Ti3C2T x /PVPA composite membranes reject ∼97% of divalent ions and ∼80% of monovalent ions with ∼0.2 Lm-2 h-1 bar-1 of water permeance when tested with brackish water, and exhibit significantly improved chlorine resistance and cost benefits over the commercial Toray membranes.

Improving permselectivity of the polyamide reverse osmosis membrane by a controlled-release sulfate radical modification

The sulfate radical (SO4.-) is an effective reactive oxidative species that can improve the permselectivity of polyamide membranes. However, the coexistence of hydroxyl radicals, which have been previously reported in a thermal-activated persulfate (PDS) system, have detrimental effects on membrane integrity and salt rejection. In this study, we adopted a facile citric acid chelated Fe(II)/PDS modification method to generate a controlled-release SO4.- oxidation condition at room temperature, which enhanced membrane performance. The rapid oxidation by Fe(II)/PDS significantly increased membrane water permeability. However, ferric oxyhydroxides were formed and deposited on the membrane surface, reducing surface hydrophilicity and negative charge. Citric acid was then introduced into the modification as a chelating agent to control the release of Fe(II) and improve the modification efficiency. The modified membrane showed further increased water permeability (from 26.0 to 53.0 L m−2h−1) and maintained a salt rejection of 98.4%. The optimized membrane enhanced surface hydrophilicity and negative charge, slightly improving anti-fouling ability. The membrane chemical composition characterization using ATR-FTIR and XPS indicated the formation of excess oxygenous groups. Furthermore, SO4.- oxidized the chlorine-sensitive sites, endowing the modified membrane with significantly improved chlorine resistance. The results from this study provide a facile SO4.--based modification method for comprehensively improving permselectivity, surface properties, and anti-fouling/anti-chlorine resistances of the polyamide membranes.

Complexation of tannic acid/silver nanoparticles on polyamide thin film composite reverse osmosis membrane for enhanced chlorine resistance and anti-biofouling properties

Reverse osmosis (RO) is a well-established and reliable desalination method that has been widely implemented on a commercial scale to resolve water scarcity issues. Constant efforts have been made to develop thin film composite membranes that can strike a balance between selectivity and permeability, while maintaining high durability towards fouling and chlorine attack. In this work, the surface of thin film composite RO membrane was modified by complexing tannic acid (TA) and silver nanoparticles (Ag NPs). TA was used for enhancing the chlorine resistance while Ag NPs act as a biocide to mitigate biofouling. Upon the formation of PA layer through interfacial polymerization, TA was chemically grafted, proceeded by in-situ reduction of Ag NPs. Transmission electron microscopy (TEM) image revealed that Ag NPs were deposited on top of the TA-PA interlayer and reduced as discrete spherical Ag NPs with diameter <15 nm. The greatest flux of 20.57 L/m2·h was produced by TFC-TA/Ag1, representing a 60 % improvement as compared to neat TFC membrane. The NaCl rejection of TFC-TA membrane was 97.83 %, which was slightly increased compared to neat TFC membrane with rejection of 95.14 %. Improved chlorine resistance and improved antibacterial properties against Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli) were witnessed for the TFC-TA/Ag1 membranes. This study demonstrates a facile chemical grafting and deposition to introduce multiple functionalities for improving the physical and separation properties of TFC RO membrane.

Mechanism of sodium-hypochlorite-induced degradation of cellulose acetate and the enhancement of its degradation resistance by chemical modification

Cellulose acetate, when used in the form of hollow fibers in the ultrafiltration stage of water treatment, is occasionally treated with sodium hypochlorite to remove organic particles such as humic acids. However, prolonged use of sodium hypochlorite reduces the strength of the membrane and facilitates its breakage. The present study was designed to reveal the degradation mechanism of cellulose acetate caused by aqueous sodium hypochlorite and to improve its resistance to this chemical. Filaments of cellulose acetate, prepared using a nonsolvent-induced phase separation method, were exposed to 2000 ppm aqueous sodium hypochlorite at 25°C for 13 days to allow for evaluation of the changes in their tensile strength, elongation at break, molecular weight, degree of substitution, and chemical structure. The tensile strength, elongation at break, and molecular weight decreased as the duration of exposure to sodium hypochlorite increased. No significant changes in the degree of substitution were observed by one-dimensional hydrogen 1 nuclear magnetic resonance, and cleavages of both glycoside bonds and carbon–carbon bonds were detected by two-dimensional nuclear magnetic resonance, revealing that base-catalyzed hydrolysis of ester groups did not play an important role in degradation. The chemical modifications of the cellulose esters, such as the introduction of pentanoyl, stearoyl, and benzoyl groups, were studied in accordance with the degradation mechanism, and cellulose esters with bulky substituents such as benzoyl groups were found to exhibit improved chlorine resistance. Perbenzoylated cellulose, which exhibited high resistance to sodium hypochlorite, is considered to be a potential membrane material for the filtration of foulant-rich raw water.

High-flux polyamide membrane with improved chlorine resistance for efficient dye/salt separation based on a new N-rich amine monomer

• Guanazole was firstly used as diamine monomer to fabricate novel TFC membrane by interfacial polymerization. • The membranes showed optimum separation selectivity for dye and NaCl with higher pure water flux (95.1 L m −2 h −1 bar −1 ). • The membranes maintained outstanding chlorine resistance after 120 h immerse in NaClO solution. Interfacial polymerization is the gold standard for manufacturing thin film composite (TFC) membranes for nanofiltration (NF) and reverse osmosis (RO). However, typical polyamide (PA) thin film composite (TFC) membranes fabricated by interfacial polymerization are inappropriate for dye wastewater zero discharge and are susceptible to oxidizing agents. In this study, by using a new N-rich amine monomer 3,5-diamino-1,2,4-triazole (DAT), a novel PA TFC membrane was fabricated for the separation of dyes and salts. It is speculated that the unique molecular structure of DAT can conducive to the formation of a less compact polyamide layer with improved chlorine resistance. The optimum membrane shows an ultrahigh pure water permeability (95.1 L/m 2 ·h·bar) and an excellent dye/salt separation selectivity for Congo red and NaCl (rejection, 99.1% and 5.8%, respectively). This is superior to that of the two commonly used dye/salt separation commercial membranes (Sepro NF 6 and NF 2A, Ultura). Furthermore, the resultant DAT/TMC TFC membranes maintained their original separation efficacy after 120 h of immersion in NaClO solution, demonstrating their good chlorine resistance. In summary, this study not only expands the application of interfacial polymerization, but also provides a new inspiration for the preparation of advanced membranes for efficient dye/salt separation.

Antifouling and antibacterial β-cyclodextrin decorated graphene oxide/polyamide thin-film nanocomposite reverse osmosis membranes for desalination applications

• β-cyclodextrin-functionalized graphene oxide enhanced membrane properties. • Membrane with improved surface hydrophilicity and pure water permeability obtained. • Superior antibacterial and antifouling properties imparted on membrane. • Potentially a robust reverse osmosis membrane with an improved life-span. Incorporating functional nanomaterials in polyamide-based membranes has opened up new alternative ways to develop reverse osmosis membranes with excellent performance, biological stability, chemical stability and longer life-span. In this study, β-cyclodextrin functionalized graphene oxide nanosheets (β-CD-f-GO) were synthesized and used to fabricate polyamide thin film nanocomposite membranes possessing excellent reverse osmosis performance, antifouling and antibacterial properties. The β-CD functionalized graphene oxide nanosheets were prepared via an amide-mediated coupling reaction between ethylenediamine-grafted β-CD and graphene oxide. The fabricated nanosheets were then embedded in the polyamide thin film composite membranes via interfacial polymerization of m-phenylenediamine in an aqueous solution containing β-CD-f-GO nanosheets with trimesoyl chloride. The influence of the nanosheets on the membrane surface chemistry, permselectivity performance, antibacterial and antifouling properties was investigated. The results revealed that the water permeation flux and antibacterial activity of the β-CD-f-GO incorporated membranes showed an improvement by approximately 38% and 45.9%, respectively, relative to an unmodified polyamide membrane, with an insignificant change in salt rejection. In addition, the nanocomposite membranes exhibited improved antifouling properties with a lower total fouling ratio of 26.2% and a higher flux recovery ratio of 88.3% in comparison to the respective 46.8% and 74.1% obtained with the unmodified polyamide membrane. Additionally, the nanomposite membranes showed long term stability over a period of 144 h of reverse osmosis testing and improved chlorine resistance. With this study, it can be concluded that the β-cyclodextrin-functionalized graphene oxide nanocomposite has a good potential in the fabrication of membranes with improved stability and lifespan for desalination applications.

Enhancing chlorine resistance in polyamide membranes with surface &amp; structure modification strategies

Abstract Higher efficient reverse osmosis (RO) membrane development is a significant issue due to the payoff among salt rejection and water flux and permissive chlorine attacking and fouling potential. Weak chlorine resistance is a distinctive challenge for composite polyamide thin-film reverse osmosis membranes. A commercial aromatic membrane was modified by grafting nitrogen-doped graphene oxide quantum dots (N-GOQDs) to enhance chlorine resistance, embedding two-dimensional MXene Ti3C2Tx, introducing synthetically reductive thioether units and oxidized graphitic carbon nitride (OGCN). In this work, salt rejection, chlorine resistance, and water flux increased compared to the pristine membrane. Comprehensive arrangement of desalination performance and chlorine resistance was achieved by varying time and concentrations of prepared chemicals. For instance, improved chlorine resistance, after 12 hours of grafting time by N-GOQDs doped membrane, was 32.8%, after 6 hours of exposure time by MXene Ti3C2Tx membrane was 27.4%, after 1 hour of exposure time by thioether membrane was 28.1% and after 40 hours of doping time by OGCN membrane was 31.3%. N-GOQDs doped membrane showed a good chlorine resistant property, but on the other hand, thioether nano units showed other properties more effectively, including water flux, salt rejection, and less reaction time.

Self‐doped sulfonated polyaniline ultrafiltration membranes with enhanced chlorine resistance and antifouling properties

AbstractMembranes heavily rely on chlorination to diminish (bio)fouling, but chlorination can also lead to membrane degradation. We developed sulfonated polyaniline (S‐PANI) ultrafiltration (UF) membranes with improved chlorine resistance and intrinsic antifouling properties. The S‐PANI membranes were synthesized through Non‐solvent Induced Phase Separation (NIPS). Membrane performance was evaluated under harsh chlorine conditions (250 ppm sodium hypochlorite for 3 days under different pH conditions). The S‐PANI membranes showed improved chlorine resistance including a stable performance without changes in model foulant BSA rejection. In contrast, PANI membranes suffered critical structural damage with complete leakage and commercial PES membranes showed a 76% increase in pure water flux and a noticeable change in BSA rejection. Small changes in S‐PANI membrane performance could be linked to membrane structural changes with pH, as confirmed by SEM, IR spectroscopy, and contact angle measurements. Additionally, the S‐PANI membranes showed better antifouling properties with a high flux recovery ratio in comparison to PANI membranes using alginic acid, humic acid, and BSA model foulants. Chemical cleaning by sodium hypochlorite re‐instated the transport properties to its initial condition. Overall, the developed S‐PANI membranes have a high chlorine tolerance and enhanced antifouling properties making them promising for a range of UF membrane applications.

Surface modification of reverse osmosis membrane with tannic acid for improving chlorine resistance

In this work, the polyamide reverse osmosis (RO) membrane surface was modified by tannic acid (TA), a cheap and commercial polyphenol, for improving chlorine resistance of membrane. TA was introduced onto the RO membrane surface via an exceptionally simple method, i.e., ethanol/TA solution activation before heat-treatment. Specifically, the membrane obtained after interfacial polymerization was treated with ethanol/TA solution before heat-treatment during the RO membrane preparation process. By surface characterization, the introduction of TA onto the RO membrane surface was confirmed. Besides, a long time (30 h) washing test showed that the modification layer was robust. Furthermore, the introduction process improved the RO membrane flux (by 27.7%) meanwhile retaining a high rejection of 98.82 ± 0.18%. Chlorination experiments were performed under the acidic (pH 4.0), neutral and alkaline (pH 8.0) conditions. The chlorinated RO membranes were characterized systematically by membrane flux and rejection evaluation, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscope. The results showed that TA as a sacrificial layer improved chlorine resistance. Importantly, the membrane modified with TA exhibited a high chlorine resistance after 8000 ppm·h chlorination exposure. This work provides a simple and effective method to improve chlorine resistance of RO membrane.

Highly improved chlorine resistance of polyamide reverse membrane by grafting layers of graphene oxide

Chemical grafting graphene oxide (GO) onto flat polyamide (PA) reverse osmosis membrane surface has been reported as a useful modification method for antibiological fouling. Here, we prepared an excellent chlorine resistance modified membranes by different layers GO grafting onto membrane surface. The influence of the layers number on the membrane separation performance and chlorine resistance was synthetically discussed. All modified membranes have good chlorine resistance, and the chlorine resistance is enhanced with the increase of grafting times. For example, NaCl rejection of pristine membrane drops from 96% to 46.2% while the GO1-grafted membrane drops from 95.7% to 59.2% and GO5-grafted membrane varies from 95.7% to 75.1% after 112 h exposure to chlorine. XPS results further prove that GO can react with chorine free radicals and protect PA fictional layers. Moreover, XPS analysis found that grafting method improved chlorine resistance more effectively than doping method by formation many choline attacking site amido bond.

Thin-film composite polyamide membrane modified by embedding functionalized boron nitride nanosheets for reverse osmosis

Modifying polyamide membranes with nanomaterials has proven effective for enhancing water flux and salt rejection and membrane resistance against fouling and chlorine. In this study, we prepared a novel thin-film nanocomposite reverse osmosis membrane by embedding functionalized boron nitride nanosheets (FBNS) into the polyamide layer via in situ interfacial polymerization process. As a result of the incorporation of FBNS, the expansion of homogeneous leaf-like structure of the polyamide layer, as indicated by the increased surface roughness as well as the thinner and more hydrophilic active layer, enhances the water permeance of membrane by 25% to 4.0 LMH/bar while maintaining a high salt rejection of 96.4%. The FBNS incorporated nanocomposite membranes also demonstrate improved chlorine resistance and performance stability under various stress test conditions when comparing to the pristine membrane. The humic acid fouling test indicates that the modified membrane has a flux recovery of over 96% after one cleaning cycle. This work provides new insights into the effect of boron nitride nanosheets on membrane network structures and separation performance and provides a scalable membrane improvement strategy based on emerging 2D nanosheets.

Chemical grafting N-GOQD of polyamide reverse osmosis membrane with improved chlorine resistance, water flux and NaCl rejection

Poor chlorine resistance shortens service life of polyamide (PA) reverse osmosis membrane. Here, nitrogen-doped graphene oxide quantum dots (N-GOQDs) were firstly applied to graft on PA membrane surface. Most grafting experiments are often accompanied by a decrease in water flux. In this study, the flux of the grafted membrane can be increased compared with commercial pristine membranes. Also, all modified membranes show better chlorine resistance than pristine ones. Specifically, N-GOQDs are integrated onto polyamide membranes through grafting method. Comprehensive regulation of chlorine resistance and desalination performance can be achieved by changing grafting conditions. For example, under the conditions of 12 h grafting time and 0.002 mg/mL of N-GOQD solution, water flux, NaCl rejection, and chlorine resistance of the modified membrane are improved by 11.1%, 2.3% and 32.8% after 280 h chlorine soaking respectively. FTIR analyses show that hydrogen bonded CO groups can be observed in the N-GOQD grafted membrane after chlorine tests, but they are destroyed and weakened in pristine membranes, which indicates that the modified membrane has better resistance to reactive chlorine.

Nanocomposite desalination membranes made of aromatic polyamide with cellulose nanofibers: synthesis, performance, and water diffusion study.

Reverse osmosis membranes of aromatic polyamide (PA) reinforced with a crystalline cellulose nanofiber (CNF) were synthesized and their desalination performance was studied. Comparison with plain PA membranes shows that the addition of CNF reduced the matrix mobility resulting in a molecularly stiffer membrane because of the attractive forces between the surface of the CNFs and the PA matrix. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy results showed complex formation between the carboxy groups of the CNF surface and the m- phenylenediamine monomer in the CNF-PA composite. Molecular dynamics simulations showed that the CNF-PA had higher hydrophilicity which was key for the higher water permeability of the synthesized nanocomposite membrane. The CNF-PA reverse osmosis nanocomposite membranes also showed enhanced antifouling performance and improved chlorine resistance. Therefore, CNF shows great potential as a nanoreinforcing material towards the preparation of nanocomposite aromatic PA membranes with longer operation lifetime due to its antifouling and chlorine resistance properties.

Layer-by-layer assembly of graphene oxide nanoplatelets embedded desalination membranes with improved chlorine resistance

Membranes with polyamide thin film active layer are used in reverse osmosis-based water desalination applications. Incorporation of graphene oxide nanoplatelets (GONPs) in the polyamide layer can alter the surface characteristics, permeability, selectivity, and can enhance the chlorine resistance of these membranes. In this study, a layer-by-layer (LbL) synthesis technique has been developed for embedding GONPs in the polyamide layer. Polyamide layers with GONPs were synthesized in various sequences, such as alternating layers of GONPs and polyamide, and GONPs on top of the polyamide layer. Incorporation of GONPs resulted in an increase of surface hydrophilicity as captured by the change of the water contact angle. Water flux and salt rejection properties of synthesized membranes have been investigated by using a dead-end cell. The salt rejection ability of membranes increased slightly with the incorporation of GONPs, while the water flux found to be similar to that observed for the pristine membranes without GONPs. Upon exposure to chlorine, GONPs embedded membranes retained salt rejection performance better than the pristine membranes. Our approach provides an alternative framework to incorporate nanoparticles in thin film membranes in a precise manner and to investigate the effect of such nanoparticles on the membrane performances.

Toward Enhancing the Chlorine Resistance of Reverse Osmosis Membranes: An Effective Strategy via an End-capping Technology.

Polyamide reverse osmosis (RO) membranes suffer performance decay when exposed to free chlorine because of their unique chemical structure. The decay limits their lifespan and increases operating cost. Herein, the secondary interfacial polymerization method was performed, for the first time, using isophthaloyl chloride (IPC) as the chain-terminating reagent, to eliminate the negative effect when the unreacted amino groups interact with chlorine. The surface zeta potential of the as-prepared membrane remained almost constant over a wide pH range, which greatly demonstrated the high conversion ratio of the end-capping procedure. However, neither the surface morphology nor the separation properties were conspicuously influenced. Because of the absence of the terminated amino groups in the polyamide layer, the IPC-modified membrane exhibited significantly improved chlorine resistance, particularly at high pH. Its desalination performance remained unchanged as the total chlorine exposure approached 10 000 ppm·h, whereas only 80.3% of the NaCl was rejected by the unmodified membrane under the same conditions. Such SIP technology can be applied directly to the commercial SW30 seawater desalination membrane, making it more tolerant to free chlorine. Overall, our results strongly proved the IPC-assisted end-capping process as a promising, practicable, and scalable technology for enhancing the chlorine resistance of an RO membrane.

Lab-scale and pilot-scale fabrication of amine-functional reverse osmosis membrane with improved chlorine resistance and antimicrobial property

Enhancing membrane flux, rejection, antimicrobial and chlorine resistance has been the focus of reverse osmosis membrane research. The permselectivity, chlorine resistance and antimicrobial properties of a polyamide (PA) membrane were improved by immobilization of self-synthesized amine functional hydantoin derivative poly(3-allyl-5,5-dimethylhydantoin-co-vinylamine) (P(ADMH-co-VAm)). The chlorine resistance and antimicrobial property of the modified membrane could be regenerated due to the reversible transition between hydantoin and N-halamine. The lab-scale virgin and modified membranes were systematically characterized, and their performances were evaluated and compared with some representative commercial membranes. The modified membrane showed similar permselectivity, but higher and regenerable chlorine resistance and antimicrobial property as compared with the commercial membrane e.g., BW30FR. Next, a pilot-scale 0.4-m wide continuous membrane production process was performed to fabricate membrane element. The permselectivity of the modified element was also improved. During the six “chlorination-sterilization” operation cycles, the element exhibited high antimicrobial property with small permselectivity changes. Thus, both the lab-scale and pilot-scale testing results demonstrated the improved performances of the modified membrane.

Codeposition of catechol–polyethyleneimine followed by interfacial polymerization for nanofiltration membranes with enhanced stability

ABSTRACTThin‐film composite (TFC) nanofiltration (NF) membranes were fabricated via the codeposition of catechol (CCh) and polyethyleneimine (PEI) followed by subsequent interfacial polymerization with trimesoyl chloride (TMC) on the surface of polysulfone ultrafiltration substrates. The detailed structures and surface properties were characterized by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, ζ potential analysis, and water contact angle measurement. The surface properties, including the roughness, hydrophilicity, surface potential, and NF performances, were facilely tuned through variation of the codeposition time of CCh–PEI for the prepared TFC membranes. The optimized membrane achieved a high rejection (ca. 93%) of MgCl2 with a flux of around 31 L m−2 h−1 under 0.7 MPa. The results also reveal that the codeposition process endowed the final membranes with much better structural stability in alcohol and improved chlorine resistance compared to commonly interfacial polymerized ones with PEI and TMC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45422.

Pressure-assisted preparation of graphene oxide quantum dot-incorporated reverse osmosis membranes: antifouling and chlorine resistance potentials

A GOQD incorporated TFN RO membrane was developed with excellent performance, high antifouling capacity and improved chlorine resistance.

Improved chlorine resistance of polyamide thin-film composite membranes with a terpolymer coating

Abstract Polyamide (PA) thin-film composite (TFC) membranes are easily degraded under the attack of active chlorine in feed water or during chemical washing. In the present work, a random terpolymer of 2-acrylamido-2-methyl propanesulfonic acid, acrylamide and 1-vinylimidazole (P(AMPS-co-Am-co-VI)) was designed as a coating material to improve the chlorine tolerance of PA TFC membrane. The terpolymer was first synthesized via conventional free radical polymerization and then coated onto commercial available PA TFC membrane by dip-coating process. The changes in surface chemistry, morphology, hydrophilicity/hydrophobicity and charge characteristics of the membrane after surface coating were investigated in detail. It was shown that the incorporation of terpolymer coating created a more neutral, hydrophilic, and smooth membrane surface. The chlorine resistance of the membranes was evaluated by comparing the permeation and separation properties of the unmodified and modified membranes after chlorine exposure. And the experimental results indicated that the chlorine tolerance of PA TFC membranes was improved significantly, especially in acid environment. The coating layer prevents the selective layer from the attack of active chlorine as a barrier layer more than a sacrificial layer. The coating material and method developed in this work can facilitate the design and manufacture of highly chlorine resistant TFC membrane for seawater desalination and industrial separation.