Antibacterial reverse osmosis composite membrane and preparation method thereof

Abstract

This invention relates to the field of membrane separation technology, and more particularly to an antibacterial reverse osmosis composite membrane and its preparation method. The preparation method includes: mixing a porous supported membrane with an aqueous solution, then mixing it with an oil solution, reacting the mixture, and drying it to obtain the antibacterial reverse osmosis composite membrane. The aqueous solution is prepared from raw materials including an aqueous monomer, a graphene oxide solution, a surfactant, a pH adjuster, additive a, glucose, and water; additive a includes dimethyl sulfoxide and / or N-methylpyrrolidone; the oil solution is prepared from raw materials including a polyfunctional acyl halide, an alkane solvent, a silver nitrate solution, sodium citrate, and water. This invention enables silver nanoparticles to achieve good dispersibility and prevents aggregation; simultaneously, the immobilized silver nanoparticles can effectively inhibit the stacking between graphene sheets, promoting synergistic antibacterial activity, resulting in a polysulfone porous membrane with excellent antibacterial effect, while also exhibiting superior water flux and desalination rate.

Description

Technical Field

[0001] This invention relates to the field of membrane separation technology, and in particular to an antibacterial reverse osmosis composite membrane and its preparation method. Background Technology

[0002] When aromatic polyamide membranes are applied in advanced water treatment technologies, their operation is affected by the quality of the raw water. Microorganisms in the water can contaminate the polyamide membrane to varying degrees, causing fouling. This leads to an increase in the pressure difference between the inlet and outlet of the water treatment system, which in turn affects the normal operation of the reverse osmosis system. During the cleaning process of polyamide membranes, sodium hypochlorite is added as a disinfectant and membrane cleaning agent to reduce microbial contamination. However, sodium hypochlorite is generally difficult to completely remove from the feed solution. Residual chlorine can damage the separation layer of the polyamide reverse osmosis membrane, resulting in a decrease in separation performance. In actual operation, the system exhibits an increase in membrane element permeate flow and a decrease in desalination rate. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide an antibacterial reverse osmosis composite membrane and its preparation method. The reverse osmosis composite membrane prepared by the present invention has superior antibacterial properties, as well as superior water flux and desalination rate.

[0004] This invention provides a method for preparing an antibacterial reverse osmosis composite membrane, comprising the following steps:

[0005] After mixing the porous support membrane with an aqueous solution, it is then mixed with an oil solution to react and dry, thus obtaining an antibacterial reverse osmosis composite membrane.

[0006] The aqueous solution is prepared from raw materials including aqueous monomers, graphene oxide solution, surfactants, pH adjusters, additive a, glucose and water;

[0007] The additive a includes dimethyl sulfoxide and / or N-methylpyrrolidone;

[0008] The oil phase solution is prepared from raw materials including polyfunctional acyl halides, alkane solvents, silver nitrate solution, sodium citrate and water.

[0009] Preferably, the aqueous monomer comprises at least one of aromatic amines and aliphatic amines;

[0010] The aqueous solution contains 2% to 3% by mass of the aqueous monomer.

[0011] Preferably, the aqueous monomer comprises at least one selected from phenylenediamine, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, N-(2-hydroxyethyl)ethylenediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, diethylenetriamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, mesitylenetriamine, piperazine, and 4-aminomethylpiperazine.

[0012] The mass concentration of the graphene oxide solution is 40–60 mg / L;

[0013] The aqueous solution contains 0.5% to 1% graphene oxide by mass.

[0014] Preferably, the surfactant comprises at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, and hexadecyltrimethylammonium bromide;

[0015] The aqueous solution contains 0.05% to 0.1% surfactant by mass.

[0016] The pH adjuster includes sodium hydroxide; the pH adjuster makes the pH of the aqueous solution 7 to 9.

[0017] Preferably, additive a comprises dimethyl sulfoxide and / or N-methylpyrrolidone;

[0018] In the aqueous solution, the mass content of additive a is 1% to 5%;

[0019] The aqueous solution contains 0.05% to 0.15% glucose by mass.

[0020] Preferably, the polyfunctional acyl halide includes at least one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, and pyromellitic acetonitrile chloride;

[0021] The oil phase solution contains 0.1% to 0.4% by mass of polyfunctional acyl halides.

[0022] Preferably, the alkane solvent includes at least one selected from trifluorotrichloroethane, n-hexane, cyclohexane, and heptane;

[0023] The alkane solvent in the oil phase solution has a mass content of 99.1% to 99.3%.

[0024] Preferably, the pH value of the silver nitrate solution is 10-12;

[0025] The oil phase solution contains 0.2% to 0.5% silver nitrate solution by mass.

[0026] The oil phase solution contains 0.05% to 0.15% sodium citrate by mass.

[0027] Preferably, the reaction temperature is 40–50°C and the reaction time is 0.5–1 min.

[0028] The present invention also provides an antibacterial reverse osmosis composite membrane prepared by the preparation method described above.

[0029] This invention provides a method for preparing an antibacterial reverse osmosis composite membrane, comprising the following steps: mixing a porous supported membrane with an aqueous solution, then mixing it with an oil solution, reacting, and drying to obtain the antibacterial reverse osmosis composite membrane; the aqueous solution is prepared from raw materials including an aqueous monomer, a graphene oxide solution, a surfactant, a pH adjuster, additive a, glucose, and water; additive a includes dimethyl sulfoxide and / or N-methylpyrrolidone; the oil solution is prepared from raw materials including a polyfunctional acyl halide, an alkane solvent, a silver nitrate solution, sodium citrate, and water. The preparation method provided by this invention enables silver nanoparticles to achieve good dispersibility and prevents aggregation; simultaneously, the immobilized silver nanoparticles can effectively inhibit the stacking between graphene sheets, thereby promoting synergistic antibacterial effects between the two, resulting in a polysulfone porous membrane with excellent antibacterial effect, and also exhibiting superior water flux and desalination rate. Attached Figure Description

[0030] Figure 1 The UV-vis spectra of the polysulfone membrane and the antibacterial reverse osmosis composite membrane after being immersed in an aqueous solution in Example 1 of the present invention;

[0031] Figure 2 The images show the Escherichia coli colony effects of the reverse osmosis composite membranes prepared in Example 1 and Comparative Example 1 of this invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides a method for preparing an antibacterial reverse osmosis composite membrane, comprising the following steps:

[0034] After mixing the porous support membrane with an aqueous solution, it is then mixed with an oil solution to react and dry, thus obtaining an antibacterial reverse osmosis composite membrane.

[0035] The aqueous solution is prepared from raw materials including aqueous monomers, graphene oxide solution, surfactants, pH adjusters, additive a, glucose and water;

[0036] The additive a includes dimethyl sulfoxide and / or N-methylpyrrolidone;

[0037] The oil phase solution is prepared from raw materials including polyfunctional acyl halides, alkane solvents, silver nitrate solution, sodium citrate and water.

[0038] In some embodiments of the present invention, the porous support membrane is a polysulfone membrane.

[0039] In this invention, the aqueous solution is prepared from raw materials including an aqueous monomer, a graphene oxide solution, a surfactant, a pH adjuster, additive a, glucose, and water.

[0040] In some embodiments of the present invention, the aqueous monomer comprises at least one of aromatic amines and aliphatic amines, preferably at least one of phenylenediamine, ethylenediamine, propylenediamine, butanediamine, hexamethylenediamine, N-(2-hydroxyethyl)ethylenediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, diethylenetriamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, mesitylenetriamine, piperazine, and 4-aminomethylpiperazine.

[0041] The aqueous solution contains 2% to 3% by mass, for example, 2.2%.

[0042] In some embodiments of the present invention, the mass concentration of the graphene oxide solution is 40–60 mg / L, for example, 50 mg / L. The graphene oxide solution is prepared according to the following method:

[0043] After mixing graphene oxide and deionized water, JFC penetrant was added dropwise, and the mixture was ultrasonically cleaned until the solution turned dark brown, thus obtaining a graphene oxide solution.

[0044] The graphene oxide was prepared by the Hummers method.

[0045] The mass ratio of the penetrant JFC to graphene oxide is 1:90 to 100, for example, 1:100.

[0046] The aqueous solution contains 0.5% to 1% graphene oxide by mass, for example, 1% or 0.5%.

[0047] In some embodiments of the present invention, the surfactant includes at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, and hexadecyltrimethylammonium bromide.

[0048] The surfactant in the aqueous solution contains 0.05% to 0.1% by mass, for example, 0.05%.

[0049] In some embodiments of the invention, the pH adjuster comprises sodium hydroxide. The pH adjuster causes the pH of the aqueous solution to be 7-9, for example, 8.

[0050] The pH adjuster in the aqueous solution contains 0.2% to 1% by mass, for example, 0.3% to 0.5%, specifically 0.4%.

[0051] In this invention, additive a comprises dimethyl sulfoxide and / or N-methylpyrrolidone. Additive a causes the water-oil interface during interfacial polymerization to be recessed towards the oil or aqueous phase, thereby increasing the specific surface area and improving the water flux of the membrane.

[0052] In the aqueous solution, the mass content of additive a is 1% to 5%, for example, 3%.

[0053] In this invention, glucose acts as a stabilizer, chelating and stabilizing silver ions, thus solving the problem of nanoparticle aggregation in the prior art.

[0054] The aqueous solution contains glucose at a mass content of 0.05% to 0.15%, for example, 0.1%.

[0055] In some embodiments of the present invention, the water is deionized water.

[0056] In some embodiments of the present invention, the aqueous solution is obtained by mixing raw materials including an aqueous monomer, a graphene oxide solution, a surfactant, a pH adjuster, additive a, glucose, and water.

[0057] In some embodiments of the present invention, mixing the porous support membrane with the aqueous solution includes immersing the porous support membrane in the aqueous solution. The mixing time is 5 to 20 seconds, for example, 20 seconds.

[0058] In some embodiments of the present invention, after mixing the porous support membrane with the aqueous solution, the method further includes removing excess aqueous solution from the porous support membrane. This removal can be achieved by vacuum dewatering.

[0059] In this invention, the oil phase solution is prepared from raw materials including polyfunctional acyl halides, alkane solvents, silver nitrate solution, sodium citrate and water.

[0060] In some embodiments of the present invention, the polyfunctional acyl halide includes at least one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, and pyromellitic methyl chloride.

[0061] The oil phase solution contains 0.1% to 0.4% by mass, for example, 0.4%.

[0062] In some embodiments of the present invention, the alkane solvent includes at least one selected from trifluorotrichloroethane, n-hexane, cyclohexane, and heptane.

[0063] The alkane solvent in the oil phase solution has a mass content of 99.1% to 99.3%, for example, 99.15%.

[0064] In some embodiments of the present invention, the pH value of the silver nitrate solution is 10-12, specifically 11. The silver nitrate solution is obtained by mixing silver nitrate and deionized water and adjusting the pH value to 10-12; the mass concentration of the silver nitrate solution is 0.2%-0.5%, for example, 0.5%. Sodium hydroxide can be used as the reagent for adjusting the pH value.

[0065] The oil phase solution contains 0.2% to 0.5% silver nitrate solution by mass, for example, 0.3% to 0.5%, specifically 0.5% or 0.35%.

[0066] In some embodiments of the present invention, the mass content of sodium citrate in the oil phase solution is 0.05% to 0.15%, for example, 0.1%.

[0067] In some embodiments of the present invention, the oil phase solution is obtained by mixing raw materials including polyfunctional acyl halides, alkane solvents, silver nitrate solution, sodium citrate and water.

[0068] In some embodiments of the present invention, further mixing with the oil phase solution includes: further immersion in the oil phase solution.

[0069] In some embodiments of the present invention, the temperature of the reaction is 40 to 50°C, for example, 40°C; and the time is 0.5 to 1 min, for example, 1 min.

[0070] In some embodiments of the present invention, the reaction is followed by: removing excess oil phase solution from the porous support membrane. The removal method may be drying. The drying temperature is 70–90°C, for example, 80°C.

[0071] In some embodiments of the present invention, after removing excess oil phase solution from the porous support membrane, rinsing and drying are further included. The rinsing time is 25-35 seconds, for example, 30 seconds. The drying temperature is 70-90°C, for example, 80°C.

[0072] The present invention also provides an antibacterial reverse osmosis composite membrane prepared by the preparation method described above.

[0073] In this invention, a polysulfone porous membrane is immersed in an aqueous solution. Due to the abundance of active oxygen-containing functional groups such as hydroxyl, carboxyl, and carbonyl groups on its surface, the graphene oxide surface carries a negative charge. Under the influence of electrostatic repulsion, graphene oxide exhibits excellent dispersibility in the solvent, is not prone to aggregation, and can directly covalently bind with the polysulfone porous membrane. GO can be firmly adsorbed onto the polysulfone porous membrane.

[0074] The polysulfone porous membrane is then immersed in the oil phase solution, with sodium citrate as the reducing agent and Ag... + It reacts with polar groups such as hydroxyl and carboxyl groups on graphene oxide to reduce silver nitrate.

[0075] The present invention does not impose any special restrictions on the source of the raw materials used above, and they can be commercially available.

[0076] To further illustrate the present invention, the following detailed description of an antibacterial reverse osmosis composite membrane and its preparation method provided by the present invention is provided in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0077] All reagents used in the following examples and comparative examples are commercially available.

[0078] In the examples, the preparation of the graphene oxide solution was as follows:

[0079] Graphene oxide was prepared by the Hummers method.

[0080] After mixing graphene oxide and deionized water, JFC penetrant was added dropwise, and the mixture was ultrasonically cleaned until the solution turned dark brown, resulting in a graphene oxide solution with a mass concentration of 50 mg / L.

[0081] The mass ratio of the penetrant JFC to graphene oxide is 1:100.

[0082] Example 1

[0083] 1) Preparation of aqueous solution: Graphene oxide solution (concentration 50 mg / L), p-phenylenediamine, sodium dodecyl sulfonate, sodium hydroxide, dimethyl sulfoxide, glucose, and deionized water were mixed evenly. In the aqueous solution, the mass content of graphene oxide solution was 1%, the mass content of p-phenylenediamine was 2.2%, the mass content of sodium dodecyl sulfonate was 0.05%, the mass content of sodium hydroxide was 0.4%, the mass content of dimethyl sulfoxide was 3%, and the mass content of glucose was 0.1%.

[0084] 2) Preparation of the oil phase solution: Trimethylbenzene chloride, n-hexane, silver nitrate solution (pH 11, mass concentration of silver nitrate solution 0.5%), sodium citrate and deionized water are mixed evenly; in the oil phase solution, the mass content of trimethylbenzene chloride is 0.4%, the mass content of n-hexane is 99.15%, the mass content of silver nitrate solution is 0.5%, and the mass content of sodium citrate is 0.1%;

[0085] 3) Immerse the polysulfone membrane in an aqueous solution for 20 seconds, remove excess aqueous solution from the polysulfone membrane by vacuum suction; then immerse it in an oil solution, react at 40°C for 1 minute, dry it in an 80°C oven to remove excess oil solution, rinse for 15 seconds, and dry it at 80°C to obtain an antibacterial reverse osmosis composite membrane.

[0086] Figure 1The UV-vis spectrum of the polysulfone membrane and the antibacterial reverse osmosis composite membrane after being immersed in an aqueous solution in Example 1 of the present invention. Figure 1 Figure a shows the polysulfone membrane immersed in an aqueous solution in Example 1 of this invention. Figure 1 Figure b in the figure is the UV-vis spectrum of the antibacterial reverse osmosis composite membrane in Example 1 of the present invention.

[0087] from Figure 1 As can be seen from Figure a, graphene oxide exhibits a strong absorption peak and a weak absorption band at approximately 232 nm and 300 nm, respectively. The absorption peak at 242 nm corresponds to the π→π* transition of the C=C backbone in graphene oxide, while the sharp peak at 300 nm corresponds to the n→π* transition of the C=O backbone, indicating that the synthesized graphene oxide surface contains carboxyl groups.

[0088] from Figure 1 As shown in Figure b, the spectrum changed significantly after loading silver nanoparticles, with a localized surface plasmon resonance (LSPR) absorption peak characteristic of silver nanoparticles appearing at 418 nm. Simultaneously, the π→π* transition of C=C redshifted from 242 nm to approximately 305 nm, likely due to the influence of the silver nanoparticles generated on the surface.

[0089] Example 2

[0090] The difference from Example 1 is that the proportions of each component in the aqueous solution are different.

[0091] In the aqueous solution, the mass content of graphene oxide solution is 0.5%, the mass content of p-phenylenediamine is 2.2%, the mass content of sodium dodecyl sulfonate is 0.05%, the mass content of sodium hydroxide is 0.4%, the mass content of dimethyl sulfoxide is 3%, and the mass content of glucose is 0.1%.

[0092] Example 3

[0093] The difference from Example 1 is that the proportions of each component in the oil phase solution are different.

[0094] In the oil phase solution, the mass content of pyromellitic chloroform is 0.4%, the mass content of n-hexane is 99.15%, the mass content of silver nitrate solution is 0.35%, and the mass content of sodium citrate is 0.1%.

[0095] Example 4

[0096] The difference from Example 1 is as follows:

[0097] Replace dimethyl sulfoxide with N-methylpyrrolidone.

[0098] Comparative Example 1 (Compared to Example 1, the aqueous phase solution did not contain graphene oxide solution, and the oil phase solution did not contain silver nitrate solution)

[0099] 1) Preparation of aqueous solution: p-phenylenediamine, sodium dodecyl sulfonate, sodium hydroxide, dimethyl sulfoxide, glucose and deionized water are mixed evenly; in the aqueous solution, the mass content of p-phenylenediamine is 2.2%, the mass content of sodium dodecyl sulfonate is 0.05%, the mass content of sodium hydroxide is 0.4%, the mass content of dimethyl sulfoxide is 3%, and the mass content of glucose is 0.1%.

[0100] 2) Preparation of the oil phase solution: Trimethylbenzene chloride, n-hexane, sodium citrate and deionized water are mixed evenly; in the oil phase solution, the mass content of trimethylbenzene chloride is 0.4%, the mass content of n-hexane is 99.15%, and the mass content of sodium citrate is 0.1%;

[0101] 3) Immerse the polysulfone membrane in an aqueous solution for 20 seconds, remove excess aqueous solution from the polysulfone membrane by vacuum suction; then immerse it in an oil solution, react at 40°C for 1 minute, dry it in an 80°C oven to remove excess oil solution, rinse for 15 seconds, and dry it at 80°C to obtain an antibacterial reverse osmosis composite membrane.

[0102] Comparative Example 2 (compared to Example 1, both the silver nitrate solution and the graphene oxide solution were in an aqueous phase)

[0103] 1) Preparation of aqueous solution: Graphene oxide solution (concentration 50 mg / L), p-phenylenediamine, sodium dodecyl sulfonate, sodium hydroxide, dimethyl sulfoxide, silver nitrate solution (pH 11, mass concentration of silver nitrate solution 0.5%), glucose, and deionized water were mixed evenly. In the aqueous solution, the mass content of graphene oxide solution was 1%, p-phenylenediamine was 2.2%, sodium dodecyl sulfonate was 0.05%, sodium hydroxide was 0.4%, dimethyl sulfoxide was 3%, silver nitrate solution was 0.5%, and glucose was 0.1%.

[0104] 2) Preparation of the oil phase solution: Trimethylbenzene chloride, n-hexane, sodium citrate and deionized water are mixed evenly; in the oil phase solution, the mass content of trimethylbenzene chloride is 0.4%, the mass content of n-hexane is 99.15%, and the mass content of sodium citrate is 0.1%;

[0105] 3) Immerse the polysulfone membrane in an aqueous solution for 20 seconds, remove excess aqueous solution from the polysulfone membrane by vacuum suction; then immerse it in an oil solution, react at 40°C for 1 minute, dry it in an 80°C oven to remove excess oil solution, rinse for 15 seconds, and dry it at 80°C to obtain an antibacterial reverse osmosis composite membrane.

[0106] Comparative Example 3 (compared to Example 1, both the silver nitrate solution and the graphene oxide solution were in an oil phase solution)

[0107] 1) Preparation of aqueous solution: p-phenylenediamine, sodium dodecyl sulfonate, sodium hydroxide, dimethyl sulfoxide, glucose and deionized water are mixed evenly; in the aqueous solution, the mass content of p-phenylenediamine is 2.2%, the mass content of sodium dodecyl sulfonate is 0.05%, the mass content of sodium hydroxide is 0.4%, the mass content of dimethyl sulfoxide is 3%, and the mass content of glucose is 0.1%.

[0108] 2) Preparation of the oil phase solution: Graphene oxide solution (concentration 50 mg / L), trimesoyl chloride, n-hexane, silver nitrate solution (pH 11, mass concentration of silver nitrate solution 0.5%), sodium citrate, and deionized water were mixed evenly; in the oil phase solution, the mass content of graphene oxide solution was 1%, the mass content of trimesoyl chloride was 0.4%, the mass content of n-hexane was 99.15%, the mass content of silver nitrate solution was 0.5%, and the mass content of sodium citrate was 0.1%.

[0109] 3) Immerse the polysulfone membrane in an aqueous solution for 20 seconds, remove excess aqueous solution from the polysulfone membrane by vacuum suction; then immerse it in an oil solution, react at 40°C for 1 minute, dry it in an 80°C oven to remove excess oil solution, rinse for 15 seconds, and dry it at 80°C to obtain an antibacterial reverse osmosis composite membrane.

[0110] Comparative Example 4

[0111] The difference from Example 1 is as follows:

[0112] The aqueous solution does not contain dimethyl sulfoxide.

[0113] Comparative Example 5

[0114] The difference from Example 1 is as follows:

[0115] The aqueous solution does not contain glucose.

[0116] Comparative Example 6

[0117] The difference from Example 1 is as follows:

[0118] The oil phase solution does not contain n-hexane.

[0119] Membrane performance testing:

[0120] 1. Water flux and desalination rate test:

[0121] 2000 mg / L NaCl was used as the test solution, with an applied pressure of 225 psi, pH = 7, and continuous operation for 0.5 h, while maintaining the temperature at 20–25 °C.

[0122] The test results are shown in Table 1.

[0123] 2. Antibacterial performance test:

[0124] Referring to the test method of GB / T-20944.3-2008, Escherichia coli was selected as the test strain. According to the national standard GB4789.36-2016 Escherichia coli O157:H7 / NM culture method, Escherichia coli was cultured on the reverse osmosis composite membranes prepared in Examples 1-4 and Comparative Examples 1-6 respectively. The bacterial solution was diluted 100 times, the number of colonies in the culture dishes under different treatment conditions was counted, and the viable bacteria concentration (W) and inhibition rate (Y) were calculated.

[0125] The calculation formula is shown in equation (1):

[0126] Y=(Wb-Wa) / Wb×100% Formula (1);

[0127] In formula (1):

[0128] Y: Antibacterial rate, %;

[0129] Wb: The concentration of viable bacteria in the flask after 18 hours of shaking contact with the standard blank sample;

[0130] Wa: The concentration of viable bacteria in the flask after the antibacterial fabric sample has been shaken and exposed to the air for 18 hours.

[0131] Test results are as follows Figure 2 As shown in Table 1.

[0132] Figure 2 The images show the Escherichia coli colony effects of the reverse osmosis composite membranes prepared in Example 1 and Comparative Example 1 of this invention. Figure 2 Figure a in the figure is an image showing the Escherichia coli colony effect of the reverse osmosis composite membrane prepared in Comparative Example 1 of the present invention. Figure 2 Figure b in the figure is an effect diagram of Escherichia coli colony in the reverse osmosis composite membrane prepared in Example 1 of the present invention.

[0133] Table 1. Performance of the reverse osmosis composite membranes prepared in Examples 1-4 and Comparative Examples 1-6

[0134]

[0135] Table 1 shows that the untreated reverse osmosis membrane (Comparative Example 1) had numerous colonies of varying sizes growing on its culture dish. Reverse osmosis membranes are highly susceptible to bacterial growth in humid and warm environments. Table 1 shows that the number of colonies reached 3724, indicating that the untreated reverse osmosis membrane had no antibacterial effect. In contrast, the number of colonies in the culture dish loaded with the RGO / Ag reverse osmosis membrane was significantly lower than that of the untreated membrane, with only 103 colonies. Calculations show that the antibacterial rate was 97.23%.

[0136] Characterization of reduction degree - Measurement of color characteristic value Δb:

[0137] Using a DatacolorTools Plus colorimeter, the loading of GO / Ag onto the porous support layer of the polysulfone substrate was characterized by measuring the absorption of different molecules of different wavelengths of radiation, with Δb (yellowness change). (GO loaded on the substrate is yellowish-brown, while Ag loaded on the substrate is pale yellow; the yellowness change Δb reflects the degree of reduction of GO / Ag on the porous support layer of the polysulfone substrate). The b-values ​​and Δb of the reverse osmosis composite membranes prepared in Examples 1-4 and Comparative Examples 1-6 before and after the interfacial polymerization reaction are shown in Table 2.

[0138] Table 2 shows the b-values ​​and Δb of the reverse osmosis composite membranes prepared in Examples 1-4 and Comparative Examples 1-6 before and after the interfacial polymerization reaction.

[0139]

[0140] As shown in Table 2, when the reaction conditions are as in Example 1, the b value is the largest, the GO / Ag has the highest load on the porous support layer of the polysulfone substrate, the Δb value is the largest, the GO / Ag has the strongest reduction degree in the porous support layer of the polysulfone substrate, and the antibacterial performance is the best.

[0141] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an antibacterial reverse osmosis composite membrane, comprising the following steps: After mixing the porous support membrane with the aqueous solution, it is then mixed with the oil solution and reacted at 40~50℃. After drying, an antibacterial reverse osmosis composite membrane is obtained. The aqueous solution is prepared from an aqueous monomer, a graphene oxide solution, a surfactant, a pH adjuster, additive a, glucose, and water; the additive a is dimethyl sulfoxide or N-methylpyrrolidone. In the aqueous solution, the mass content of the aqueous monomer is 2%~3%, the mass content of the graphene oxide solution is 0.5%~1%, the mass content of the surfactant is 0.05%~0.1%, the mass content of additive a is 1%~5%, and the mass content of glucose is 0.05%~0.15%; the pH adjuster makes the pH value of the aqueous solution 7~9; the mass concentration of the graphene oxide solution is 40~60 mg / L. The oil phase solution was prepared from a polyfunctional acyl halide, an alkane solvent, a silver nitrate solution, sodium citrate, and water. In the oil phase solution, the mass content of the polyfunctional acyl halide is 0.1%~0.4%, the mass content of the silver nitrate solution is 0.2%~0.5%, the mass content of the sodium citrate is 0.05%~0.15%, and the mass content of the alkane solvent is 99.1%~99.3%; the pH value of the silver nitrate solution is 10~12.

2. The production method according to claim 1, characterized by, The aqueous monomer includes at least one of aromatic amines and aliphatic amines.

3. The preparation method according to claim 1, characterized in that, The aqueous monomers include at least one of phenylenediamine, ethylenediamine, propylenediamine, butanediamine, hexamethylenediamine, N-(2-hydroxyethyl)ethylenediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, diethylenetriamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, mesitylenetriamine, piperazine, and 4-aminomethylpiperazine.

4. The method of claim 1, wherein, The surfactant includes at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, and hexadecyltrimethylammonium bromide.

5. The preparation method according to claim 1, characterized in that, The polyfunctional acyl halide includes at least one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, and pyromellitic methyl chloride.

6. The preparation method according to claim 1, characterized in that, The alkane solvent includes at least one of trifluorotrichloroethane, n-hexane, cyclohexane, and heptane.

7. The preparation method according to claim 1, characterized in that, The reaction time is 0.5 to 1 minute.

8. The antibacterial reverse osmosis composite membrane prepared by any one of claims 1 to 7.

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