CN112619420A - Loofah sponge modified composite reverse osmosis membrane and preparation method thereof - Google Patents
Loofah sponge modified composite reverse osmosis membrane and preparation method thereof Download PDFInfo
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- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/025—Reverse osmosis; Hyperfiltration
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- B01D69/12—Composite membranes; Ultra-thin membranes
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- B01D71/26—Polyalkenes
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- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
- B01D71/34—Polyvinylidene fluoride
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- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/40—Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
- B01D71/42—Polymers of nitriles, e.g. polyacrylonitrile
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- B01D71/60—Polyamines
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- B01D71/06—Organic material
- B01D71/58—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
- B01D71/62—Polycondensates having nitrogen-containing heterocyclic rings in the main chain
- B01D71/64—Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
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- B01D71/06—Organic material
- B01D71/74—Natural macromolecular material or derivatives thereof
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D2325/00—Details relating to properties of membranes
- B01D2325/14—Membrane materials having negatively charged functional groups
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D2325/00—Details relating to properties of membranes
- B01D2325/36—Hydrophilic membranes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Abstract
The invention relates to a loofah sponge fiber modified composite reverse osmosis membrane and a preparation method thereof. The method is characterized in that activated loofah sponge dispersion liquid and membrane casting liquid are mixed according to a proportion to prepare a loofah sponge blending base membrane, then the base membrane is soaked in a mixed solution of polyamine and polybasic acyl chloride to prepare a cross-linked desalting layer, and then active group molecules with negative charges are grafted on the surface of the cross-linked desalting layer of the prepared composite reverse osmosis membrane through a surface grafting technology to obtain the loofah sponge modified composite reverse osmosis membrane. The composite reverse osmosis membrane prepared by the method has the advantages of high water flux and desalination rate, high mechanical strength, good pressure resistance, good pollution resistance and prolonged service life, and active groups grafted by the crosslinked desalination layer are negatively charged on the surface.
Description
Technical Field
The invention relates to the technical field of reverse osmosis membranes, in particular to a preparation method of a reverse osmosis membrane and the reverse osmosis membrane prepared by the preparation method. The composite reverse osmosis membrane is prepared by blending and modifying the loofah sponge fibers, so that the water flux and the salt rejection rate of the reverse osmosis membrane are greatly improved, and the pollution resistance and the mechanical strength of the reverse osmosis membrane are enhanced.
Background
Reverse osmosis is a pressure-driven membrane separation process, has the advantages of high purification efficiency, low cost, environmental protection and the like, and is widely applied to the fields of pure water preparation, drinking water purification, wastewater treatment, seawater and brackish water desalination, food and beverage, medical pharmacy, petrochemical industry, landfill leachate, metal cutting waste liquid and the like. The high-performance composite reverse osmosis membrane is the core of the reverse osmosis membrane separation technology. However, the conventional composite reverse osmosis membrane has the defects of easy pollution, poor mechanical strength and oxidation resistance, no pressure resistance, difficult cleaning and the like.
Currently, reverse osmosis membranes on the market are flat composite membranes consisting of a base membrane and a surface desalting layer. The base membrane is an ultrafiltration membrane taking non-woven fabric as a base and plays a role in increasing mechanical strength; the desalination layer is typically an ultra-thin dense separation layer obtained by in situ interfacial polymerization at the surface of the support membrane. The mechanical strength of the base membrane directly influences the compression resistance of the reverse osmosis membrane, and the hydrophilicity and the negative charge of the surface of the desalination layer membrane are main reasons for increasing the pollution resistance of the membrane. Therefore, the key points of solving the pollution problem of the composite reverse osmosis membrane, not withstanding pressure and prolonging the service life of the reverse osmosis membrane are that the mechanical strength of the basement membrane is enhanced, and the surface hydrophilicity and the negative charge of the desalting layer are enhanced.
The loofah sponge is a natural and renewable high polymer and is mainly used as a biological filler and an adsorbing material for substances such as oil, heavy metal and the like. Loofah sponge is used for preparation and performance research of antibacterial cellulose and chitosan derivative blend membranes (Zhou Xiao Dong. preparation and performance research of antibacterial cellulose/chitosan derivative blend membranes [ D ]. Qingdao; Qingdao university, 2008), but the loofah sponge is not applied to blend modification research of composite reverse osmosis membranes.
Disclosure of Invention
Problems to be solved by the invention
The reverse osmosis membrane aims to solve the problems of poor pollution resistance, low mechanical strength and no pressure resistance of the conventional reverse osmosis membrane and prolong the service life of the reverse osmosis membrane. The application discloses a loofah sponge blending modified composite reverse osmosis membrane method, which comprises the steps of putting loofah sponge subjected to activation pretreatment into a mixed solvent to prepare a dispersion liquid, adding the loofah sponge dispersion liquid and porous polymer particles into the solvent to prepare a membrane casting liquid, and soaking non-woven fabrics into the membrane casting liquid to prepare a loofah sponge fiber blending base membrane, so that the mechanical strength of the base membrane is enhanced. And then soaking the base membrane in a mixed solution of polyamine and polyacyl chloride for interfacial polymerization to prepare a crosslinked desalting layer, and chemically or physically grafting active group molecules with negative charges on the crosslinked desalting layer to increase the anti-pollution performance of the reverse osmosis membrane. The main film preparation steps are as follows:
(1) preparation of loofah sponge mixed dispersion liquid
Placing retinervus Luffae fructus powder in 20wt% strong sodium oxide solution for activating pretreatment, with mass ratio of 1-20wt%, heating in constant temperature water bath, and stirring for 30 min. After the treatment is finished, the loofah sponge is washed to be neutral by deionized water, washed by absolute ethyl alcohol for 3 times and soaked for 30 min. And finally, placing the mixture in an electric heating constant-temperature air blast drying box for drying. Placing the activated and pretreated loofah sponge fiber into an N.N-dimethylacetamide solvent, heating and stirring in a constant-temperature water bath until a gel flocculent system is formed, freezing and standing for 2 hours, and continuously stirring at room temperature for 10 hours to prepare the loofah sponge fiber dispersion.
(2) Preparation of composite reverse osmosis membrane base film
Mixing porous polymer particles, loofah sponge fiber dispersion liquid, pore-forming agent and N, N-dimethylacetamide solvent to prepare polymer membrane casting solution, preparing loofah sponge blending base membrane by adopting an immersion precipitation phase inversion method, coating the polymer membrane casting solution on non-woven fabric, and soaking the non-woven fabric and the non-woven fabric in water to prepare a porous polymer supporting layer base membrane;
(3) preparation of composite reverse osmosis membrane
Soaking the porous polymer supporting layer base membrane prepared in the step (2) in an amine mixture solution mixed by an aliphatic heterocyclic compound or an aromatic compound, an acid-binding agent and water until the adsorption is saturated, taking out the porous polymer supporting layer base membrane, and purging surface residues with nitrogen until the porous polymer supporting layer base membrane is dried; and then soaking the porous polymer support layer obtained by drying treatment in an organic phase solution of acyl chloride compounds, taking out the solvent remained on the surface of the membrane by purging with nitrogen after 20-30s of soaking, and carrying out post-treatment to obtain the composite reverse osmosis membrane.
(4) Active group molecules grafted with negative electricity by composite reverse osmosis membrane desalting layer
And (4) soaking the reverse osmosis membrane prepared in the step (3) in a tetrahydrofuran aqueous solution containing active group molecules for 10-30min, taking out, and purging with nitrogen until the reverse osmosis membrane is dried to obtain the modified loofah sponge fiber modified composite reverse osmosis membrane.
The preparation method is characterized in that the loofah sponge fiber is subjected to activation pretreatment, and the loofah sponge fiber dispersion liquid prepared by mixing the activated loofah sponge fiber and an N.N-dimethylacetamide solvent is 1-60wt%, preferably 1-40 wt%.
The preparation method is characterized in that the porous polymer is one or more of porous polysulfone, porous polyethersulfone, porous polyimide, porous sulfonated polyethersulfone, porous polyvinylidene fluoride, porous polyacrylonitrile, porous polypropylene, porous polyphenylene amine, porous polyetherimide and porous polyvinyl chloride, and the mass ratio of the porous polymer solution is 20-30wt%, preferably 22-28 wt%.
The preparation method is characterized in that the mass ratio of the loofah sponge dispersion liquid to the porous polymer particles to the pore-forming agent to the solvent is (30-45): (20-30): (1-10): (80-95). The pore-forming agent is polyvinyl alcohol, and the solvent is N, N-dimethylacetamide.
The preparation method is characterized in that the aliphatic heterocyclic compound is one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, 1, 4-cyclohexanediamine, 1, 2-cyclohexanediamine, piperazine, pyrazole, N-ethylpiperazine, N-methylpiperazine, glycol amine, ethanolamine, polyethyleneimine, triethylamine, diethylenetriamine and diglycolamine; the aromatic compound is one or more of aniline, m-phenylenediamine, p-phenylenediamine, amicrol, 1,3, 5-triaminobenzene, 2, 4-diaminobenzoic acid, 1,2, 4-triaminobenzene, 3, 5-diaminobenzoic acid, xylylenediamine and 2, 4-diaminotoluene; the weight ratio of aliphatic amine to aromatic amine in the amine mixture is 1-60wt%, preferably 1-20wt%, and the mass concentration of the aliphatic amine to aromatic amine in the oil-water interface reaction is 3-8 wt%.
The preparation method is characterized in that the acyl chloride compound is one or more of trimesoyl chloride, biphenyl diformyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, benzenediformyl chloride, terephthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, benzoyl chloride, phenylenediamine sulfonyl chloride, hexanetrioyl chloride, cyclobutane and tetracarbonyl; the organic phase is cyclohexane, the weight ratio of the acyl chloride compound to the organic phase solution is 0.1-1wt%, preferably 0.1-0.5wt%, and the mass concentration of the organic phase solution in the oil-water interface reaction is 0.05-0.5 wt%.
The preparation method is characterized in that the acid-binding agent is at least one of sodium carbonate, dipotassium hydrogen phosphate, sodium hydroxide and potassium hydroxide, and the mass concentration is 0.05-5 wt%; the acid-binding agent is used for adjusting the pH value to 9-12.
The preparation method is characterized in that the active group molecule is at least one of salicylic acid, maleic anhydride, benzoic acid, acetic acid, polyacrylic acid, polyethylene glycol, epoxy E-51, polyethyleneimine, ethanolamine, triethylamine, glycerol ether, bisphenol A, polyhexamethylene guanidine hydrochloride and tetramethyl dipropylidene triamine; dissolving active group molecules in tetrahydrofuran to obtain an active group aqueous solution, wherein the mass concentration of the active group molecules is 0.2-3wt%, and the mass concentration of the tetrahydrofuran is 0.03-2 wt%.
The preparation method is characterized in that the reverse osmosis membrane is coated on the surface of a desalination layer of the reverse osmosis membrane or the reverse osmosis membrane with the desalination layer is immersed in an aqueous solution with negatively charged active groups. Wherein the temperature of the aqueous solution is 50-120 deg.C, preferably 60-90 deg.C, and the treatment time is 0.5-30min, preferably 1-10 min.
The preparation method is characterized in that the charged active group molecules contain polar functional groups with negative charges such as epoxy groups, carboxyl groups, acid anhydrides, acyl chlorides, hydroxyl groups, sulfonyl groups and amino groups, and the polar functional groups can perform intermolecular bonding reaction with the amino groups, the acyl chlorides, the carboxylate radicals and the like in the crosslinking desalting layer through a surface grafting technology, so that the surface of the desalting layer is negatively charged, the anti-pollution performance of the reverse osmosis membrane is enhanced, and the service life is prolonged.
Effects of the invention
The strength of the base membrane of the loofah sponge modified composite reverse osmosis membrane prepared by the method is greatly enhanced, and the surface hydrophilicity of the reverse osmosis membrane is increased and negative charges are carried out by grafting active group molecules on the crosslinked desalting layer of the reverse osmosis membrane, so that the mechanical strength resistance of the reverse osmosis membrane is improved, the pressure resistance and the pollution resistance of the reverse osmosis membrane are improved, and the service life of the reverse osmosis membrane is prolonged.
The application also provides the composite reverse osmosis membrane prepared according to the preparation method. The composite reverse osmosis membrane can be used for separation and concentration technologies in the fields of water quality purification, food and beverage, chemical printing and dyeing, industrial wastewater, environmental protection and the like.
Drawings
The attached figure (figure 1) is a structural schematic diagram of the composite reverse osmosis membrane. Wherein, 1 is a loofah sponge blended basement membrane, 2 is a cross-linking desalting layer, and 3 is an active group molecular layer.
Detailed Description
The technical solution of the present application is further specifically described below with reference to the following examples, but the present application is not limited thereto.
Each of the raw materials in the examples was purchased from the market.
(1) Loofah activating pretreatment
Adding retinervus Luffae fructus powder into 20wt% strong sodium oxide solution, heating and stirring in thermostatic water bath for 60min, and washing retinervus Luffae fructus with deionized water to neutrality. Then rinsing with absolute ethyl alcohol for three times, and soaking for 30 min. And finally, drying the loofah sponge in an oven at 60 ℃ to obtain the activated loofah sponge fiber.
(2) Preparation of activated loofah sponge fiber dispersion liquid
Mixing activated loofah sponge fiber and N, N-dimethylacetamide in a mass ratio of 1-40wt% in a container, heating and stirring in a constant-temperature water bath until loofah sponge is dissolved to form gel flocculence, standing in a freezing chamber for 2h, taking out, and continuously stirring at room temperature for 10h to obtain loofah sponge fiber dispersion liquid.
Example 1
Mixing the loofah sponge fiber dispersion liquid, the porous polymer, the pore-forming agent and the N, N-dimethylacetamide according to the mass ratio of 30:20:1:80, and dissolving and defoaming to prepare the membrane casting liquid containing the loofah sponge fibers. Uniformly coating the membrane casting solution on a non-woven fabric, and soaking the non-woven fabric and water to prepare a porous polymer supporting layer base membrane; soaking the prepared base membrane in an amine mixture solution mixed by an aliphatic heterocyclic compound or an aromatic compound, an acid-binding agent and water until the base membrane is saturated by adsorption, taking out, and purging surface residues with nitrogen until the surface residues are dried, wherein the mass ratio of aliphatic amine to aromatic amine is 1-20wt%, the acid-binding agent is sodium hydroxide, and the mass concentration is 0.05 wt%; and then, soaking the dried base membrane in a cyclohexane solution of acyl chloride compound, wherein the mass ratio of acyl chloride to cyclohexane is 0.1-1wt%, and after the base membrane is soaked for 20s, taking out the base membrane and purging the residual solvent on the surface of the membrane by using nitrogen to obtain the composite reverse osmosis membrane. And finally, soaking the prepared composite reverse osmosis membrane in tetrahydrofuran aqueous solution containing active group molecules for 2min at the temperature of 70 ℃, wherein the mass ratio of the active group molecules to the tetrahydrofuran is 20-3%, taking out the composite reverse osmosis membrane, and blowing the composite reverse osmosis membrane by using nitrogen until the composite reverse osmosis membrane is dried to obtain the modified loofah sponge fiber modified composite reverse osmosis membrane.
Example 2
Mixing the loofah sponge fiber dispersion liquid, the porous polymer, the pore-forming agent and the N, N-dimethylacetamide according to the mass ratio of 35:25:5:85, and dissolving and defoaming to prepare the membrane casting liquid containing the loofah sponge fibers. Uniformly coating the membrane casting solution on a non-woven fabric, and soaking the non-woven fabric and water to prepare a porous polymer supporting layer base membrane; soaking the prepared base membrane in an amine mixture solution mixed by an aliphatic heterocyclic compound or an aromatic compound, an acid-binding agent and water until the base membrane is saturated by adsorption, taking out, and blowing surface residues with nitrogen until the surface residues are dried, wherein the mass ratio of aliphatic amine to aromatic amine is 1-30wt%, the acid-binding agent is sodium hydroxide, and the mass concentration is 0.15 wt%; and then, soaking the dried base membrane in a cyclohexane solution of acyl chloride compound, wherein the mass ratio of acyl chloride to cyclohexane is 0.5-1wt%, and after soaking for 30s, taking out the base membrane and purging the residual solvent on the surface of the membrane by using nitrogen to obtain the composite reverse osmosis membrane. And finally, soaking the prepared composite reverse osmosis membrane in tetrahydrofuran aqueous solution containing active group molecules for 5min at the temperature of 80 ℃, wherein the mass ratio of the active group molecules to the tetrahydrofuran is 100-5%, taking out the composite reverse osmosis membrane, and blowing the composite reverse osmosis membrane by using nitrogen until the composite reverse osmosis membrane is dried to obtain the modified loofah sponge fiber modified composite reverse osmosis membrane.
Example 3
Mixing the loofah sponge fiber dispersion liquid, the porous polymer, the pore-forming agent and the N.N-dimethylacetamide according to the mass ratio of 45:30:10:95, and dissolving and defoaming to prepare the membrane casting liquid containing the loofah sponge fibers. Uniformly coating the membrane casting solution on a non-woven fabric, and soaking the non-woven fabric and water to prepare a porous polymer supporting layer base membrane; soaking the prepared base membrane in an amine mixture solution mixed by an aliphatic heterocyclic compound or an aromatic compound, an acid-binding agent and water until the base membrane is saturated by adsorption, taking out, and purging surface residues with nitrogen until the surface residues are dried, wherein the mass ratio of aliphatic amine to aromatic amine is 1-40wt%, the acid-binding agent is sodium hydroxide, and the mass concentration is 0.15 wt%; and then, soaking the dried base membrane in a cyclohexane solution of acyl chloride compound, wherein the mass ratio of acyl chloride to cyclohexane is 0.1-0.8wt%, and after the base membrane is soaked for 40s, taking out the base membrane and purging the residual solvent on the surface of the membrane by using nitrogen to obtain the composite reverse osmosis membrane. And finally, soaking the prepared composite reverse osmosis membrane in a tetrahydrofuran aqueous solution containing active group molecules for 10min at the temperature of 90 ℃, wherein the mass ratio of the active group molecules to the tetrahydrofuran is 300-20%, taking out the composite reverse osmosis membrane, and blowing the composite reverse osmosis membrane by using nitrogen until the composite reverse osmosis membrane is dried to obtain the modified loofah sponge fiber modified composite reverse osmosis membrane.
Comparative example 1
Mixing porous polymer particles, a pore-forming agent and an N.N-dimethylacetamide solvent according to a mass ratio of 25:5:85 to prepare a polymer membrane casting solution; coating the polymer membrane casting solution on non-woven fabrics, and soaking the non-woven fabrics and the non-woven fabrics in water to prepare a porous polymer supporting layer base membrane; then soaking the porous polymer supporting layer base membrane in an amine mixture solution mixed by an aliphatic heterocyclic compound or an aromatic compound, an acid-binding agent and water until the adsorption is saturated, taking out the porous polymer supporting layer base membrane, and purging surface residues with nitrogen until the porous polymer supporting layer base membrane is dried, wherein the mass ratio of aliphatic amine to aromatic amine is 1-20wt%, the acid-binding agent is sodium hydroxide, and the mass concentration is 0.1 wt%; and then soaking the membrane in an organic phase solution of acyl chloride compound, taking out the membrane after soaking for 20s, purging residual solvent on the surface of the membrane by using nitrogen, and performing post-treatment to obtain the composite reverse osmosis membrane.
Test and results
Sodium chloride removal test
Samples of the reverse osmosis membranes prepared in comparative examples and examples 1 to 3 were tested on a membrane test bed, and the salt rejection, water flux and tensile strength after the membrane was operated for 30min were measured under test conditions of 2000ppm sodium chloride in an aqueous solution of water, an operating pressure of 1.55Mpa, a temperature of 25 ℃, a pH of 6 to 7.5, and the results are summarized in table 1.
TABLE 1 Water flux, salt rejection and tensile Strength of membranes
Magnesium chloride removal test
Samples of the reverse osmosis membranes prepared in the comparative example and the examples 1 to 3 were tested on a membrane test bed, and the salt rejection, water flux and tensile strength after the membrane was operated for 30min were measured under the test conditions of 4000ppm of magnesium chloride in the raw water, an operating pressure of 1.55MPa, a temperature of 25 ℃ and a pH value of 6.5 to 7.5. The results of the experiments are summarized in table 2.
TABLE 2 Water flux, salt rejection and tensile Strength of the membranes
Anti-contamination test
The reverse osmosis membrane prepared in the comparative example and examples 1 to 3 was immersed in a staphylococcus aureus culture solution, cultured at 37 ℃ for 24 hours, taken out, and tested on a membrane test bench, and the salt rejection, water flux and tensile strength of the membrane after 30min of operation were measured under the conditions of 2000ppm sodium chloride in water, 1.55Mpa operating pressure, 25 ℃ temperature, and 6.5 to 7.5 pH. The results of the experiments are summarized in table 3.
TABLE 3 Water flux, salt rejection and tensile Strength of the membranes
In conclusion, by comparing the data in tables 1 to 3, it is found that the salt rejection rate and the water flux of the loofah sponge modified composite reverse osmosis membrane are obviously higher than those of the composite reverse osmosis membrane under different test conditions. This shows that the modified composite reverse osmosis membrane prepared by the method has the advantages of high desalting and high water yield, not only improving the tensile strength of the composite reverse osmosis membrane, but also enhancing the pollution resistance, thereby improving the cleaning resistance of the composite reverse osmosis membrane and prolonging the service life of the composite reverse osmosis membrane.
The above-mentioned embodiments further describe the objects, technical solutions, embodiments and experiments of the present invention in detail. However, the above description is only an example of the present invention and is not intended to limit the present invention. All changes and modifications that come within the spirit of the invention are desired to be protected.
Claims (7)
1. Method for modifying composite reverse osmosis membrane by loofah sponge fibers
A method for modifying a composite reverse osmosis membrane by loofah sponge is characterized by comprising loofah sponge fibers, non-woven fabrics, porous polymers, a cross-linked desalting layer and an active group molecule group, and the preparation method comprises the following steps:
(1) preparation of loofah sponge mixed dispersion liquid
Placing the loofah sponge powder into a sodium oxide solution for activation pretreatment, and placing the pretreated loofah sponge fiber into an N.N-dimethylacetamide solvent to prepare a loofah sponge fiber dispersion solution;
(2) mixing the loofah sponge fiber dispersion liquid with the membrane casting liquid to prepare a polymer membrane casting liquid, and preparing a loofah sponge blending base membrane by adopting an immersion precipitation phase inversion method;
(3) dipping the base membrane prepared in the step (2) in an aliphatic heterocyclic compound or an aromatic compound to obtain a porous polymer supporting layer;
(4) dipping the porous polymer support layer obtained by the treatment in the step (3) in an organic phase solution of acyl chloride compounds, carrying out interfacial polymerization reaction on polyamine and polybasic acyl chloride at the solution interface to form a cross-linked desalting layer, and carrying out post-treatment to obtain the composite reverse osmosis membrane;
(5) and (4) soaking the reverse osmosis membrane prepared in the step (4) in an aqueous solution containing active group molecules, taking out and drying the aqueous solution to obtain the modified loofah sponge fiber modified composite reverse osmosis membrane.
2. The loofah sponge fiber modified composite reverse osmosis membrane according to claim 1, wherein the loofah sponge fiber is subjected to activation pretreatment, and the loofah sponge fiber dispersion prepared by mixing the activated loofah sponge fiber and an N.N-dimethylacetamide solvent is 1-60wt%, preferably 1-35 wt%.
3. The loofah sponge fiber modified composite reverse osmosis membrane according to claim 1, wherein the porous polymer is one or more of porous polysulfone, porous polyethersulfone, porous polyimide, porous sulfonated polyethersulfone, porous polyvinylidene fluoride, porous polyacrylonitrile, porous polypropylene, porous polyphenylene amine, porous polyetherimide and porous polyvinyl chloride, and the mass ratio of the porous polymer solution is 20-30wt%, preferably 22-28 wt%.
4. The loofah sponge fiber modified composite reverse osmosis membrane of claim 1, wherein the aliphatic heterocyclic compound is one or more of ethylenediamine, propylenediamine, butylenediamine, hexylenediamine, 1, 4-cyclohexanediamine, 1, 2-cyclohexanediamine, piperazine, pyrazole, N-ethylpiperazine, N-methylpiperazine, ethylenediamine amine, ethanolamine, polyethyleneimine, triethylamine, diethylenetriamine, and diglycolamine; the aromatic compound is one or more of aniline, m-phenylenediamine, p-phenylenediamine, amicrol, 1,3, 5-triaminobenzene, 2, 4-diaminobenzoic acid, 1,2, 4-triaminobenzene, 3, 5-diaminobenzoic acid, xylylenediamine and 2, 4-diaminotoluene; the weight ratio of aliphatic amine to aromatic amine in the amine mixture is 1-60wt%, preferably 1-20wt%, and the mass concentration of the aliphatic amine to aromatic amine in the oil-water interface reaction is 3-8 wt%.
5. The loofah sponge fiber modified composite reverse osmosis membrane according to claim 1, wherein the acyl chloride compound is one or more of trimesoyl chloride, biphenyldicarbonyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, benzenedicarbonyl chloride, terephthaloyl chloride, isophthaloyl chloride, benzenedicarbonyl chloride, benzoyl chloride, phenylenediamine sulfonyl chloride, hexanetrioyl chloride, cyclobutane and tetrachloride; the weight ratio of the acid chloride compound to the organic phase solution is 0.1 to 1wt%, preferably 0.1 to 0.5wt%, and the mass concentration thereof at the time of oil-water interface reaction is 0.05 to 0.5 wt%.
6. The loofah sponge fiber-modified composite reverse osmosis membrane according to claim 1, wherein the active group molecule is at least one of salicylic acid, maleic anhydride, benzoic acid, acetic acid, polyacrylic acid, polyethylene glycol, epoxy E-51, polyethyleneimine, ethanolamine, triethylamine, glycerol ether, bisphenol a, and polyhexamethylene guanidine hydrochloride, tetramethyl dipropyl trimethylene triamine; wherein the mass concentration of the active group molecules is 0.2-3 wt%.
7. The composite reverse osmosis membrane prepared by the preparation method of any one of claims 1-7.
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