CN115869779A - Efficient bacteriostatic anti-pollution reverse osmosis membrane and preparation method thereof - Google Patents
Efficient bacteriostatic anti-pollution reverse osmosis membrane and preparation method thereof Download PDFInfo
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- CN115869779A CN115869779A CN202310189706.6A CN202310189706A CN115869779A CN 115869779 A CN115869779 A CN 115869779A CN 202310189706 A CN202310189706 A CN 202310189706A CN 115869779 A CN115869779 A CN 115869779A
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- 239000012528 membrane Substances 0.000 title claims abstract description 132
- 238000001223 reverse osmosis Methods 0.000 title claims abstract description 65
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 230000003385 bacteriostatic effect Effects 0.000 title claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 97
- 239000004372 Polyvinyl alcohol Substances 0.000 claims abstract description 64
- 229920002451 polyvinyl alcohol Polymers 0.000 claims abstract description 64
- 239000004952 Polyamide Substances 0.000 claims abstract description 47
- 229920002647 polyamide Polymers 0.000 claims abstract description 47
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 claims abstract description 45
- 229920001661 Chitosan Polymers 0.000 claims abstract description 39
- 238000000576 coating method Methods 0.000 claims abstract description 37
- 239000011248 coating agent Substances 0.000 claims abstract description 36
- 238000010438 heat treatment Methods 0.000 claims abstract description 33
- 238000000926 separation method Methods 0.000 claims abstract description 28
- -1 silver ions Chemical class 0.000 claims abstract description 22
- 229910001961 silver nitrate Inorganic materials 0.000 claims abstract description 22
- 229920002492 poly(sulfone) Polymers 0.000 claims abstract description 21
- 239000004094 surface-active agent Substances 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 13
- 239000000243 solution Substances 0.000 claims description 129
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 39
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 36
- 239000007864 aqueous solution Substances 0.000 claims description 34
- 239000012071 phase Substances 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 29
- 239000008367 deionised water Substances 0.000 claims description 28
- 229910021641 deionized water Inorganic materials 0.000 claims description 28
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 26
- 239000008346 aqueous phase Substances 0.000 claims description 20
- 150000001412 amines Chemical class 0.000 claims description 11
- 150000001266 acyl halides Chemical class 0.000 claims description 10
- 239000002798 polar solvent Substances 0.000 claims description 10
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 8
- 239000003960 organic solvent Substances 0.000 claims description 8
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 claims description 7
- 239000012530 fluid Substances 0.000 claims description 7
- 229940018564 m-phenylenediamine Drugs 0.000 claims description 7
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N dimethyl sulfoxide Natural products CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 5
- 239000000178 monomer Substances 0.000 claims description 5
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims description 4
- 150000004982 aromatic amines Chemical class 0.000 claims description 4
- UWCPYKQBIPYOLX-UHFFFAOYSA-N benzene-1,3,5-tricarbonyl chloride Chemical compound ClC(=O)C1=CC(C(Cl)=O)=CC(C(Cl)=O)=C1 UWCPYKQBIPYOLX-UHFFFAOYSA-N 0.000 claims description 4
- FDQSRULYDNDXQB-UHFFFAOYSA-N benzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1 FDQSRULYDNDXQB-UHFFFAOYSA-N 0.000 claims description 4
- GEYOCULIXLDCMW-UHFFFAOYSA-N 1,2-phenylenediamine Chemical compound NC1=CC=CC=C1N GEYOCULIXLDCMW-UHFFFAOYSA-N 0.000 claims description 3
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 claims description 3
- CNPVJWYWYZMPDS-UHFFFAOYSA-N 2-methyldecane Chemical compound CCCCCCCCC(C)C CNPVJWYWYZMPDS-UHFFFAOYSA-N 0.000 claims description 3
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 claims description 3
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 3
- LHIJANUOQQMGNT-UHFFFAOYSA-N aminoethylethanolamine Chemical compound NCCNCCO LHIJANUOQQMGNT-UHFFFAOYSA-N 0.000 claims description 3
- FYXKZNLBZKRYSS-UHFFFAOYSA-N benzene-1,2-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC=C1C(Cl)=O FYXKZNLBZKRYSS-UHFFFAOYSA-N 0.000 claims description 3
- SSJXIUAHEKJCMH-UHFFFAOYSA-N cyclohexane-1,2-diamine Chemical compound NC1CCCCC1N SSJXIUAHEKJCMH-UHFFFAOYSA-N 0.000 claims description 3
- GEQHKFFSPGPGLN-UHFFFAOYSA-N cyclohexane-1,3-diamine Chemical compound NC1CCCC(N)C1 GEQHKFFSPGPGLN-UHFFFAOYSA-N 0.000 claims description 3
- VKIRRGRTJUUZHS-UHFFFAOYSA-N cyclohexane-1,4-diamine Chemical compound NC1CCC(N)CC1 VKIRRGRTJUUZHS-UHFFFAOYSA-N 0.000 claims description 3
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 claims description 3
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 claims description 3
- GHAIYFTVRRTBNG-UHFFFAOYSA-N piperazin-1-ylmethanamine Chemical compound NCN1CCNCC1 GHAIYFTVRRTBNG-UHFFFAOYSA-N 0.000 claims description 3
- AOHJOMMDDJHIJH-UHFFFAOYSA-N propylenediamine Chemical compound CC(N)CN AOHJOMMDDJHIJH-UHFFFAOYSA-N 0.000 claims description 3
- KIDHWZJUCRJVML-UHFFFAOYSA-N putrescine Chemical compound NCCCCN KIDHWZJUCRJVML-UHFFFAOYSA-N 0.000 claims description 3
- LXEJRKJRKIFVNY-UHFFFAOYSA-N terephthaloyl chloride Chemical compound ClC(=O)C1=CC=C(C(Cl)=O)C=C1 LXEJRKJRKIFVNY-UHFFFAOYSA-N 0.000 claims description 3
- 230000000844 anti-bacterial effect Effects 0.000 abstract description 48
- 239000002131 composite material Substances 0.000 abstract description 20
- 239000004332 silver Substances 0.000 abstract description 16
- 229910052709 silver Inorganic materials 0.000 abstract description 16
- 239000002105 nanoparticle Substances 0.000 abstract description 14
- 230000002829 reductive effect Effects 0.000 abstract description 13
- 238000009991 scouring Methods 0.000 abstract description 8
- 239000003638 chemical reducing agent Substances 0.000 abstract description 7
- AYKOTYRPPUMHMT-UHFFFAOYSA-N silver;hydrate Chemical compound O.[Ag] AYKOTYRPPUMHMT-UHFFFAOYSA-N 0.000 abstract description 5
- 239000003381 stabilizer Substances 0.000 abstract description 4
- 239000010410 layer Substances 0.000 description 81
- 210000004379 membrane Anatomy 0.000 description 73
- 230000004907 flux Effects 0.000 description 24
- 238000003756 stirring Methods 0.000 description 23
- 238000011033 desalting Methods 0.000 description 11
- 230000008569 process Effects 0.000 description 11
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical group [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 description 10
- 235000011187 glycerol Nutrition 0.000 description 10
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 238000010612 desalination reaction Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 230000009467 reduction Effects 0.000 description 9
- 150000003839 salts Chemical class 0.000 description 9
- 241000894006 Bacteria Species 0.000 description 8
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000001816 cooling Methods 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000004132 cross linking Methods 0.000 description 6
- 241000588724 Escherichia coli Species 0.000 description 5
- 230000006196 deacetylation Effects 0.000 description 5
- 238000003381 deacetylation reaction Methods 0.000 description 5
- 230000014759 maintenance of location Effects 0.000 description 5
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 150000001299 aldehydes Chemical class 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 244000005700 microbiome Species 0.000 description 4
- 239000003002 pH adjusting agent Substances 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 229920002101 Chitin Polymers 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 238000012695 Interfacial polymerization Methods 0.000 description 3
- 239000003899 bactericide agent Substances 0.000 description 3
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 3
- 230000002045 lasting effect Effects 0.000 description 3
- 230000000813 microbial effect Effects 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- 210000002345 respiratory system Anatomy 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000003115 biocidal effect Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 230000003204 osmotic effect Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 235000019333 sodium laurylsulphate Nutrition 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 101710134784 Agnoprotein Proteins 0.000 description 1
- 206010059866 Drug resistance Diseases 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 1
- 239000006087 Silane Coupling Agent Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000001263 acyl chlorides Chemical group 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000003373 anti-fouling effect Effects 0.000 description 1
- 210000002469 basement membrane Anatomy 0.000 description 1
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- 238000011161 development Methods 0.000 description 1
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- 239000003651 drinking water Substances 0.000 description 1
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- 238000004043 dyeing Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
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- 229920002521 macromolecule Polymers 0.000 description 1
- 238000009285 membrane fouling Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000001728 nano-filtration Methods 0.000 description 1
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- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
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Classifications
-
- 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
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention provides an efficient bacteriostatic anti-pollution reverse osmosis membrane and a preparation method thereof. Firstly, sequentially coating a water phase solution and an oil phase solution on a polysulfone supporting layer of a base film and drying to form a polyamide separation layer on the polysulfone supporting layer; then rinsing is carried out; and finally, coating the surface of the polyamide separation layer with a post-treatment solution, and then carrying out heat treatment and ultraviolet irradiation treatment to obtain the efficient bacteriostatic anti-pollution reverse osmosis membrane. The post-treatment solution is prepared by matching polyvinyl alcohol, a surfactant, chitosan, silver nitrate and water in a certain proportion, PVA (polyvinyl alcohol) is used as a reducing agent, chitosan is used as a stabilizing agent, silver ions are reduced and solidified into Ag through heat treatment and ultraviolet irradiation, PVA molecules and Ag nano particles are inserted or embedded in a polyamide layer, so that an antibacterial layer and the polyamide layer are crosslinked together, the composite film with the surface provided with a crosslinked PVA structure and containing the Ag nano particles is obtained, and the antibacterial property and the scouring resistance can be improved.
Description
Technical Field
The invention relates to the field of water treatment, in particular to an efficient bacteriostatic anti-pollution reverse osmosis membrane and a preparation method thereof.
Background
The reverse osmosis technology is a high-end water treatment technology generated by using an osmotic pressure principle, realizes the separation of water and different solutes, has a simpler operation mode compared with other technologies, and can effectively remove organic matters and colloids such as salts, micromolecular acids, aldehydes, phenols and the like in water. The application fields include seawater desalination, brackish water desalination, drinking water purification, industrial ultrapure water production and reuse treatment of industrial wastewater of papermaking, electroplating, petrochemical industry, pharmacy, printing and dyeing and the like. With the expansion of the application field of the membrane, the pollution problem of the reverse osmosis membrane becomes more and more serious. The reverse osmosis membrane fouling problem has long been one of the major problems that have restricted the development and progress of reverse osmosis membrane separation technology, particularly microbial fouling of reverse osmosis membranes, which is a dynamic series of processes in which microbes diffuse and adsorb to the membrane surface and then release extracellular polymeric substances to adhere to and deposit, grow and reproduce and metabolize until they mature and die. The pollution of the reverse osmosis membrane can cause the increase of boundary layer resistance and local osmotic pressure, the driving force of dissolution-diffusion is reduced, the separation effect of the membrane is deteriorated, the water yield and the efficiency are reduced, the service life of the membrane is shortened after long-term operation, the manufacturing cost is improved, and the membrane is difficult to recover.
At present, with the continuous application of reverse osmosis membranes in reclaimed water recycling, microbial bacteria become a main pollution source, so that bactericides need to be added into a reverse osmosis system regularly, but conventional bactericides are easy to generate drug resistance, the performance of the reverse osmosis membranes can be influenced, and certain pollution can be generated to the environment.
In order to improve the anti-pollution performance of the membrane, a conventional anti-pollution method is to coat a PVA (polyvinyl alcohol) coating on the surface of a functional layer, but in the method, because the anti-pollution layer has small adhesive force with the surface of the reverse osmosis membrane, the anti-pollution layer can gradually fall off in the working process of the reverse osmosis membrane, so that the anti-pollution performance of the reverse osmosis membrane is gradually lost, and the anti-pollution performance is general in antibacterial property.
In addition, there is a research report that inorganic nanoparticles having a bactericidal effect are added to or surface-coated on an oil phase in a reverse osmosis membrane to improve antibacterial ability of a composite membrane. For example, CN102580579A and CN105435647A add nanoparticles into the antifouling layer, but the specific surface area of the nanomaterial is large, the surface free energy is high, the agglomeration phenomenon can be spontaneously generated, and the compatibility with the high polymer is poor, the uniform dispersion in the high polymer solution is difficult, and the problem of unstable antibacterial effect exists.
Patent application CN106268362A discloses a preparation method of an antibacterial composite film, comprising the following steps: (1) Mixing a macromolecule containing a plurality of hydroxyl groups, a silane coupling agent containing sulfydryl, acid, aldehyde and a solvent to prepare coating liquid; (2) Coating the coating liquid on a nanofiltration membrane or a reverse osmosis membrane for a thermal crosslinking reaction to obtain a composite membrane with a crosslinking layer on the surface; (3) Contacting the crosslinked layer of the composite membrane with an aqueous solution of silver nitrate; (4) And (4) heating the composite film obtained in the step (3). Wherein the polymer containing multiple hydroxyl groups can be polyvinyl alcohol or chitosan. The method comprises the steps of coating a solution containing a reducing agent on a desalting layer, carrying out heat treatment, coating a solution containing silver ions, and carrying out heat reduction. Moreover, the antibacterial layer in the method needs to be subjected to heat treatment twice, the temperature required by the heat treatment is higher, the reaction time is longer, the production cost is increased while the production efficiency is reduced, and the desalting rate and the water flux of the membrane are reduced due to the influence of repeated heat treatment on the desalting layer of the membrane.
Disclosure of Invention
In view of the above, the invention provides an efficient bacteriostatic anti-pollution reverse osmosis membrane and a preparation method thereof. The reverse osmosis membrane provided by the invention can effectively improve the antibacterial property and the scouring resistance, and ensure excellent water flux and desalination rate.
The invention provides a preparation method of an efficient bacteriostatic anti-pollution reverse osmosis membrane, which comprises the following steps:
a) Coating a water phase solution on a polysulfone support layer of a base membrane, then coating an oil phase solution and drying to form a polyamide separation layer on the polysulfone support layer so as to obtain a nascent state polyamide reverse osmosis membrane;
wherein,
the aqueous phase solution comprises a base solution and a pH regulator; the base fluid comprises the following components in percentage by mass:
0.5% -5% of polyfunctional amine;
0.05% -2% of a surfactant;
3% -10% of a polar solvent;
the balance of water;
the oil phase solution comprises the following components in percentage by mass:
0.05% -0.3% of polyfunctional acyl halide;
the balance of organic solvent;
b) Rinsing the nascent state polyamide reverse osmosis membrane to obtain a rinsed membrane;
c) Coating the post-treatment solution on the surface of the polyamide separation layer of the rinsing membrane, and then carrying out heat treatment and ultraviolet irradiation treatment to obtain the efficient bacteriostatic anti-pollution reverse osmosis membrane;
wherein,
the post-treatment solution comprises the following components in percentage by mass:
1% -3% of polyvinyl alcohol;
0.05% -2% of a surfactant;
5% -30% of chitosan;
0.05 to 8 percent of silver nitrate
The balance of water.
Preferably, in step c), the molecular weight of the polyvinyl alcohol is 150000 to 300000Da.
Preferably, in step c), the heat treatment conditions are: 60 to 90 ℃ for 2 to 8min.
Preferably, in step c), the ultraviolet irradiation treatment conditions are as follows: the power of an ultraviolet lamp is 80 to 180W, and the irradiation time is 2 to 8min.
Preferably, in step a):
in the aqueous phase solution, the pH regulator is an alkaline regulator;
the dosage of the pH regulator is to ensure that the pH value of the aqueous phase solution reaches 7 to 9;
the polyfunctional amine is at least one of aromatic amine, aliphatic amine and alicyclic amine;
the polyfunctional acyl halide is an aromatic acyl chloride monomer.
Preferably, the polyfunctional amine is at least one of m-phenylenediamine, ethylenediamine, propylenediamine, butylenediamine, hexylenediamine, N- (2-hydroxyethyl) ethylenediamine, 1, 2-diaminocyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, diethylenetriamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, trimesamine, piperazine, and 4-aminomethylpiperazine;
the polyfunctional acyl halide is at least one of trimesoyl chloride, phthaloyl chloride, isophthaloyl chloride and terephthaloyl chloride.
Preferably, in step a):
the polar solvent is dimethyl sulfoxide and/or N-methylpyrrolidone.
The organic solvent is at least one of n-hexane, isopar G and Isopar L.
Preferably, in step b), the rinsing comprises sequentially performing the following rinsing steps:
b1 Rinsing with deionized water;
b2 Rinsing with an aqueous isopropanol solution;
b3 Rinsing with an aqueous citric acid solution;
b4 Rinsing with deionized water;
b5 Rinsing with an aqueous glycerol solution.
Preferably, in the step b 1), the temperature of the deionized water is 15 to 30 ℃, and the rinsing time is 1 to 5min;
in the step b 2), the mass percentage concentration of the isopropanol aqueous solution is 1% -5%, the temperature of the isopropanol aqueous solution is 50-80 ℃, and the rinsing time is 2-10 min;
in the step b 3), the mass percentage concentration of the citric acid aqueous solution is 1-5%, the temperature of the citric acid aqueous solution is 50-80 ℃, and the rinsing time is 2-10 min;
in the step b 4), the temperature of deionized water is 15 to 30 ℃, and the rinsing time is 1 to 5min;
in the step b 5), the mass percentage concentration of the glycerol aqueous solution is 2% -6%, the temperature of the glycerol aqueous solution is 15-30 ℃, and the rinsing time is 2-10 min.
The invention also provides the efficient bacteriostatic anti-pollution reverse osmosis membrane prepared by the preparation method in the technical scheme.
The preparation method comprises the steps of firstly, sequentially coating a water phase solution and an oil phase solution on a polysulfone supporting layer of a base film and drying to form a polyamide separation layer on the polysulfone supporting layer; then rinsing is carried out; and finally, coating the surface of the polyamide separation layer with a post-treatment solution, and then performing heat treatment and ultraviolet irradiation treatment to form an antibacterial layer, thereby obtaining the efficient bacteriostatic anti-pollution reverse osmosis membrane. The post-treatment solution is prepared by matching polyvinyl alcohol, a surfactant, chitosan, silver nitrate and water in a certain proportion, PVA (polyvinyl alcohol) is used as a reducing agent, chitosan is used as a stabilizing agent, silver ions are reduced and solidified into Ag through heat treatment and ultraviolet irradiation, PVA molecules and Ag nano particles are inserted or embedded in the polyamide layer, and therefore the antibacterial layer and the polyamide layer are crosslinked together. The Ag surface is oxidized to free a trace amount of Ag in the use process of the membrane + Can destroy the electron transmission system, the respiratory system and the material transmission system of the microorganism, and when the thallus loses activity, the silver ions Ag + The bacteria are dissociated from the bacteria and are repeatedly sterilized, so that the antibacterial effect of the membrane is outstanding and lasting; moreover, after the PVA layer is solidified and reduced by silver ions, the mechanical strength of the PVA layer and the adhesion force of the PVA layer to the surface of a reverse osmosis membrane are increased, the PVA layer is more resistant to scouring, and the scouring resistance of the membrane is improved; meanwhile, chitosan plays a role in chelating and stabilizing silver ions, and solves the problems of aggregation phenomenon of nano particles and unstable antibacterial effect in the prior art; in addition, the chitosan has antibacterial capability and is cooperated with the nano-silver for antibiosis to form a composite antibacterial effect.
Test results show that the initial water flux of the reverse osmosis membrane disclosed by the invention reaches more than 45.8gfd, the initial desalination rate reaches more than 99.48%, after the reverse osmosis membrane is flushed by a raw water solution of escherichia coli for 24 hours, the water flux retention rate of the membrane can reach more than 91%, the desalination rate reduction amount is less than 0.08%, and the reverse osmosis membrane has excellent water flux, desalination rate and antibacterial scouring resistance.
Detailed Description
The invention provides a preparation method of an efficient bacteriostatic anti-pollution reverse osmosis membrane, which comprises the following steps:
a) Coating a water phase solution on a polysulfone support layer of a base membrane, then coating an oil phase solution and drying to form a polyamide separation layer on the polysulfone support layer so as to obtain a nascent state polyamide reverse osmosis membrane;
wherein,
the aqueous phase solution comprises a base fluid and a pH regulator; the base fluid comprises the following components in percentage by mass:
0.5% -5% of polyfunctional amine;
0.05% -2% of a surfactant;
3% -10% of a polar solvent;
the balance of water;
the oil phase solution comprises the following components in percentage by mass:
0.05% -0.3% of polyfunctional acyl halide;
the balance of organic solvent;
b) Rinsing the nascent state polyamide reverse osmosis membrane to obtain a rinsed membrane;
c) Coating the post-treatment solution on the surface of the polyamide separation layer of the rinsing membrane, and then carrying out heat treatment and ultraviolet irradiation treatment to obtain the efficient bacteriostatic anti-pollution reverse osmosis membrane;
wherein,
the post-treatment solution comprises the following components in percentage by mass:
1% -3% of polyvinyl alcohol;
0.05% -2% of a surfactant;
5% -30% of chitosan;
0.05% -8% of silver nitrate;
the balance of water.
Concerning step a)：
a) And coating a water phase solution on a polysulfone support layer of the base membrane, then coating an oil phase solution and drying to form a polyamide separation layer on the polysulfone support layer so as to obtain the nascent state polyamide reverse osmosis membrane.
[ with respect to the base film ]:
in the present invention, the type of the base film is not particularly limited, and is a composite base film with a polysulfone support layer, which is conventional in the art, that is, the composite base film comprises a base material layer and a polysulfone support layer compounded on the surface of the base material layer. The kind of the substrate layer is not particularly limited, and may be any one of those conventional in the art, such as a nonwoven fabric.
[ with respect to the aqueous phase solution ]:
in the present invention, the aqueous phase solution comprises: base liquid and pH regulator. Wherein the base liquid comprises the following components in percentage by mass:
0.5% -5% of polyfunctional amine;
0.05% -2% of a surfactant;
3% -10% of a polar solvent;
water (I) and (4) the balance.
Wherein,
the polyfunctional amine is preferably at least one of aromatic amine, aliphatic amine and alicyclic amine, and more preferably at least one of m-phenylenediamine, ethylenediamine, propylenediamine, butylenediamine, hexylenediamine, N- (2-hydroxyethyl) ethylenediamine, 1, 2-diaminocyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, diethylenetriamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, pyromellitic triamine, piperazine and 4-aminomethylpiperazine. In the invention, the content of the polyfunctional amine in the base solution is 0.5-5%, specifically 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%.
The surfactant is preferably sodium dodecyl benzene sulfonate and/or sodium lauryl sulfate. In the invention, the content of the surfactant in the base solution is 0.05-2%, specifically 0.05%, 0.10%, 0.50%, 1.0%, 1.5%, 2.0%.
The solvent in the aqueous phase solution is a polar solvent, and the water-oil interface is sunken towards an oil phase or an aqueous phase when interfacial polymerization occurs by adopting the polar solvent so as to increase the specific surface area and improve the water flux of the membrane, which is not feasible if other common non-polar organic solvents are adopted. In the present invention, the polar solvent is preferably dimethyl sulfoxide and/or N-methylpyrrolidone. In the invention, the content of the polar solvent in the base solution is 3-10%, and specifically can be 3%, 4%, 5%, 6%, 7%, 8%, 9% and 10%.
The water is preferably deionized water. The water is used as the balance, namely, the water is used for complementing 100 percent.
In the invention, the preparation mode of the base solution is not particularly limited, and the 4 materials are mixed uniformly.
In the present invention, the aqueous phase solution further comprises a pH adjuster. The pH adjuster is preferably an alkaline pH adjuster, more preferably NaOH. In the invention, the dosage of the pH regulator is preferably such that the pH value of the aqueous phase solution reaches 7 to 9, and the pH value of the aqueous phase solution is controlled under the above conditions, which is favorable for absorption of byproduct hydrochloric acid molecules in the interfacial polymerization process and formation of polyamide with high crosslinking degree, and if the pH value is too low or too high, amide bond is easy to hydrolyze, which affects the separation performance of the polyamide separation layer. The pH may specifically be 7, 7.5, 8, 8.5, 9. In the invention, when preparing the aqueous phase solution, the base solution is prepared, and after the base solution is obtained, the pH value is adjusted by adding the pH regulator into the base solution, thus obtaining the aqueous phase solution.
[ with respect to the oil phase solution ]:
in the invention, the oil phase solution comprises the following components in percentage by mass:
0.05% -0.3% of polyfunctional acyl halide;
the balance of organic solvent.
Wherein,
the polyfunctional acyl halide is preferably an aromatic acid chloride monomer. In the present invention, the aromatic acid chloride monomer is preferably at least one of trimesoyl chloride, phthaloyl chloride, isophthaloyl chloride and terephthaloyl chloride. In the invention, the content of the polyfunctional acyl halide in the oil phase solution is 0.05-0.3%, specifically 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%.
The organic solvent is preferably at least one of n-hexane, isopar G and Isopar L. The organic solvent is used as the balance, namely, the balance is 100%.
In the invention, the preparation method of the oil phase solution is not particularly limited, and the oil phase solution is prepared by uniformly mixing the materials.
According to the invention, the polysulfone support layer of the base film is coated with the aqueous phase solution and then with the oil phase solution. The coating method of the present invention is not particularly limited, and may be a conventional coating operation in the art. In the present invention, after the aqueous solution is applied, the surface excess aqueous solution is preferably also removed, and specifically, the excess aqueous solution can be removed by roller rolling. After applying the oil phase solution, the surface excess oil phase solution is preferably also removed, in particular by roller rolling.
According to the present invention, after the aqueous phase solution and the oil phase solution are sequentially applied, drying is performed. In the present invention, the drying temperature is preferably 40 to 80 ℃, and specifically 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃. The drying time is preferably 1 to 5min, and specifically may be 1min, 2min, 3min, 4min, and 5min. In the drying process, the water phase solution and the oil phase solution are subjected to interfacial polymerization reaction on a polysulfone supporting layer to form a polyamide separation layer, so that the nascent state polyamide reverse osmosis membrane is obtained.
Concerning step b)：
b) And rinsing the nascent state polyamide reverse osmosis membrane to obtain a rinsed membrane.
In the present invention, the rinsing preferably comprises sequentially performing the following rinsing steps:
b1 Rinsing with deionized water);
b2 Rinsing with an aqueous isopropyl alcohol solution;
b3 Rinsing with an aqueous citric acid solution;
b4 Rinsing with deionized water);
b5 Using an aqueous glycerol solution.
Wherein,
the temperature of the rinsing liquid in each step is preferably as follows: the temperature of the deionized water in the step b 1) is lower than that of the isopropanol aqueous solution in the step b 2), the temperature of the citric acid aqueous solution in the step b 3) is higher than that of the deionized water in the step b 4), and the temperature of the citric acid aqueous solution in the step b 3) is higher than that of the glycerin aqueous solution in the step b 5). Specifically, the membrane material may be sequentially passed through 5 rinsing tanks, and the above 5 rinsing steps may be performed, respectively.
[ with respect to step b1]:
the temperature of the deionized water is preferably 15 to 30 ℃, and specifically can be 15 ℃, 20 ℃, 25 ℃ and 30 ℃. The rinsing time is preferably 1 to 5min, and specifically may be 1min, 2min, 3min, 4min, or 5min.
[ with respect to step b2]:
the temperature of the isopropanol aqueous solution is preferably 50 to 80 ℃, and specifically can be 50 ℃, 60 ℃, 70 ℃ and 80 ℃. The mass percentage concentration of the isopropanol aqueous solution is preferably 1% -5%, and specifically can be 1%, 2%, 3%, 4% and 5%. The rinsing time is preferably 2 to 10min, and specifically may be 2min, 5min, or 10min.
[ with respect to step b3]:
the temperature of the aqueous solution of citric acid is preferably 50 to 80 ℃, and specifically 50 ℃, 60 ℃, 70 ℃ and 80 ℃. The mass percentage concentration of the citric acid aqueous solution is preferably 1% -5%, and specifically can be 1%, 2%, 3%, 4% and 5%. The rinsing time is preferably 2 to 10min, and specifically may be 2min, 5min, or 10min.
[ with respect to step b4]:
the temperature of the deionized water is preferably 15 to 30 ℃, and specifically can be 15 ℃, 20 ℃, 25 ℃ and 30 ℃. The rinsing time is preferably 1 to 5min, and specifically may be 1min, 2min, 3min, 4min, or 5min.
[ with respect to step b5]:
the temperature of the glycerol aqueous solution is preferably 15 to 30 ℃, and specifically can be 15 ℃, 20 ℃, 25 ℃ and 30 ℃. The mass percentage concentration of the glycerol aqueous solution is preferably 2-6%, and specifically can be 2%, 3%, 4%, 5% and 6%. The rinsing time is preferably 2 to 10min, and specifically may be 2min, 5min and 10min.
The steps b 1) to b 5) are carried out, wherein the first step is a process of rinsing by deionized water without adding a rinsing agent at normal temperature to cool and stabilize the membrane just taken out of the oven, and preliminarily rinsing reactant residues; rinsing with an isopropanol aqueous solution, and rinsing again to remove residual reactants and further improve the flux of the nascent polyamide reverse osmosis membrane through swelling; rinsing with a citric acid aqueous solution to further remove the residue of aromatic amine, so that the reverse osmosis membrane is prevented from yellowing due to oxidation in the storage or use process, and the performance of the reverse osmosis membrane is improved; rinsing with deionized water to remove residual reactant and rinsing agent; and the fifth step is rinsing with glycerin water solution, and the glycerin fills the pores of the polyamide layer to prevent collapse and membrane flux reduction. The invention sequentially carries out five-step rinsing according to the sequence, and is beneficial to ensuring the membrane separation performance by matching in sequence.
Concerning step c)：
c) And coating the post-treatment solution on the surface of the polyamide separation layer of the rinsing membrane, and then carrying out heat treatment and ultraviolet irradiation treatment to obtain the efficient bacteriostatic anti-pollution reverse osmosis membrane.
[ with respect to the post-treatment solution ]:
in the invention, the post-treatment solution comprises the following components in percentage by mass:
1% -3% of polyvinyl alcohol;
0.05% -2% of a surfactant;
5% -30% of chitosan;
0.05% -8% of silver nitrate;
the balance of water.
Wherein,
the polyvinyl alcohol (PVA) is preferably one having a molecular weight of 150000 to 300000da, and when the molecular weight is too high, the water passage resistance through the film increases, and when the molecular weight is too low, the PVA layer is difficult to be stably adsorbed on the film (easy to peel), and the hydrophilicity and stain resistance are reduced. The molecular weight may be 150000Da, 160000Da, 170000Da, 180000Da, 190000Da, 200000Da, 210000Da, 220000Da, 230000Da, 240000Da, 250000Da, 260000Da, 270000Da, 280000Da, 290000Da, 300000Da. In the invention, the content of the polyvinyl alcohol in the post-treatment solution is 1% -3%, and specifically can be 1.0%, 1.5%, 2.0%, 2.5% and 3.0%.
The surfactant is preferably sodium dodecyl benzene sulfonate and/or sodium lauryl sulfate. In the invention, the content of the surfactant in the post-treatment solution is 0.05% -2%, and specifically can be 0.05%, 0.1%, 0.5%, 1.0%, 1.5% and 2.0%.
The chitosan (chitosan) is also called deacetylated chitin, is obtained by deacetylating chitin (chitin) widely existing in nature, and has good inhibiting effect on bacteria, yeast, fungi and other microorganisms. In the invention, the chitosan is preferably chitosan with deacetylation degree of more than 95%, and the grade is medical grade. In the invention, the content of chitosan in the post-treatment solution is 5-30%, specifically 5%, 10%, 15%, 20%, 25% and 30%.
The source of the silver nitrate is not particularly limited, and is a commercial product available on the market. In the invention, the content of the silver nitrate in the post-treatment solution is 0.05-8%, specifically 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%.
The water is preferably deionized water. The water is used as the balance, namely, the water is used for making up 100 percent.
In the present invention, the post-treatment solution is preferably prepared by the following preparation method: adding water into a container, starting stirring, adding polyvinyl alcohol, heating and continuously stirring, then cooling, adding a surfactant, chitosan and silver nitrate, and stirring in a dark place to obtain a post-treatment solution. Wherein, the container is preferably a high-temperature kettle. The stirring speed is preferably 40 to 50r/min. The heating temperature is preferably 60 to 90 ℃, and specifically 60 ℃, 70 ℃, 80 ℃, 90 ℃, and more preferably 80 ℃. The time for which stirring is continued after heating is preferably 2 hours or longer. The cooling is preferably to room temperature. After cooling, the contents of the container are preferably transferred to a stirring tank, followed by the addition of surfactant, chitosan and silver nitrate. The light-shielding stirring speed is preferably 30 to 60r/min; the stirring time is preferably 20 to 40min, and more preferably 30min. In some embodiments of the present invention, the above preparation method comprises the following steps: adding water into the high-temperature kettle; opening a stirring switch, setting the rotating speed to be 40 to 50r/min, and adding polyvinyl alcohol; opening the heating and setting the temperature to 80 ℃, and stirring for more than 2 hours; cooling, transferring to a stirring barrel, adding a surfactant, chitosan and silver nitrate, and stirring for 30min in a dark place to obtain a post-treatment solution.
According to the invention, a post-treatment solution is applied to the surface of the polyamide separation layer of the rinsing membrane. The coating mode is not particularly limited in the present invention, and may be a conventional coating operation. In the present invention, after the post-treatment solution is applied, it is preferable to leave it standing for 2 to 10 seconds (i.e., the post-treatment solution is in contact with the film for the above-mentioned time), and then remove the excess post-treatment solution from the surface of the film. The removal can be carried out in particular by roller rolling to remove excess aftertreatment solution.
According to the present invention, after the above treatment, heat treatment is performed. In the present invention, the heat treatment may be performed in an oven. In the present invention, the heat treatment temperature is preferably 60 to 90 ℃, and specifically 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, more preferably 80 ℃. The time of the heat treatment is preferably 2 to 8min, and specifically can be 2min, 3min, 4min, 5min, 6min, 7min and 8min.
According to the present invention, after the above heat treatment, ultraviolet light irradiation treatment is performed. In the invention, the power of the ultraviolet lamp used for the ultraviolet irradiation is preferably 80 to 180W, and specifically may be 80W, 90W, 100W, 110W, 120W, 130W, 140W, 150W, 160W, 170W and 180W. The time of ultraviolet irradiation is preferably 2 to 8min, and specifically can be 2min, 3min, 4min, 5min, 6min, 7min and 8min. After the treatment, an antibacterial layer is formed on the polyamide separation layer of the rinsing membrane, and the efficient antibacterial and mildewproof antipollution reverse osmosis membrane is obtained.
The invention mixes polyvinyl alcohol, surface active agent, chitosan, silver nitrate and water in a certain proportion to prepare post-treatment solution, the chitosan is the product of chitosan deacetylation, the surface of the chitosan contains a large amount of amino and hydroxyl, and the chitosan can generate chelation with silver ions to generate complex Ag (CTS): NO 3 (ii) a The surfactant can prevent the coating liquid from being polymerized into water drops, and can uniformly disperse the water drops into smaller particles to be coated on the desalting layer (namely the polyamide separation layer); is subjected to heat treatmentAfter the ultraviolet irradiation treatment, silver ions are reduced to silver in situ, meanwhile, partial hydroxyl groups on the PVA molecules react with redundant acyl chloride groups on the desalting layer, the PVA molecules and the Ag nano particles are inserted or embedded in the polyamide layer, so that the antibacterial layer and the polyamide layer are crosslinked together, the surface of the antibacterial layer is provided with a PVA crosslinking structure, and the crosslinking structure contains the Ag nano particles, so that the efficient antibacterial and mildewproof anti-pollution reverse osmosis membrane is obtained.
The invention also provides the efficient bacteriostatic anti-pollution reverse osmosis membrane prepared by the preparation method in the technical scheme.
The preparation method provided by the invention comprises the steps of firstly, sequentially coating a water phase solution and an oil phase solution on a polysulfone supporting layer of a base film and drying to form a polyamide separation layer on the polysulfone supporting layer; then rinsing is carried out; and finally, coating the surface of the polyamide separation layer with a post-treatment solution, and then performing heat treatment and ultraviolet irradiation treatment to form an antibacterial layer, thereby obtaining the efficient bacteriostatic anti-pollution reverse osmosis membrane. The post-treatment solution is prepared by matching polyvinyl alcohol, a surfactant, chitosan, silver nitrate and water in a certain proportion, PVA (polyvinyl alcohol) is used as a reducing agent, chitosan is used as a stabilizing agent, silver ions are reduced and solidified into Ag through heat treatment and ultraviolet irradiation, PVA molecules and Ag nano particles are inserted or embedded in the polyamide layer, and therefore the antibacterial layer and the polyamide layer are crosslinked together. The Ag surface is oxidized to dissociate trace Ag in the using process of the membrane + Can destroy the electron transmission system, the respiratory system and the material transmission system of the microorganism, and when the thallus loses activity, the silver ions Ag + The bacteria are dissociated from the bacteria and are repeatedly sterilized, so that the antibacterial effect of the membrane is outstanding and lasting; moreover, after the PVA layer is solidified and reduced by silver ions, the mechanical strength of the PVA layer and the adhesion force of the PVA layer to the surface of a reverse osmosis membrane are increased, the PVA layer is more resistant to scouring, and the scouring resistance of the membrane is improved; meanwhile, the chitosan plays a role in chelating and stabilizing silver ions, and solves the problems of agglomeration of nano particles and unstable antibacterial effect in the prior art; in addition, the chitosan has antibacterial capability and is cooperated with the nano-silver for antibacterial, so that a composite antibacterial effect is formed.
The invention has the following beneficial effects:
1. the post-treatment solution is prepared by matching polyvinyl alcohol, a surfactant, chitosan, silver nitrate and water according to a certain proportion, the PVA is used as a reducing agent, the chitosan is used as a stabilizing agent, silver ions are reduced and cured into Ag through heat treatment and ultraviolet irradiation, and PVA molecules and Ag nano particles are interpenetrated or embedded in the polyamide layer, so that the antibacterial layer and the polyamide layer are crosslinked together. The Ag surface is oxidized to dissociate trace Ag in the using process of the membrane + Can destroy the electron transmission system, the respiratory system and the material transmission system of the microorganism, and when the thallus loses activity, the silver ions Ag + And the membrane is dissociated from the thallus for repeated sterilization, so that the antibacterial effect of the membrane is outstanding and lasting.
2. The problems of aggregation phenomenon of nano particles and unstable antibacterial effect in the prior art are solved by utilizing the chelating and stabilizing effects of chitosan on silver ions.
3. The chitosan has antibacterial ability and is cooperated with nano-silver for antibiosis to form a composite antibacterial effect. Can effectively improve the influence of microbial bacteria on the reverse osmosis membrane and reduce the putting amount and the putting frequency of the bactericide.
4. The antibacterial layer is formed only by coating once, the process is consistent with the conventional reverse osmosis membrane production line, the equipment and process change is small, and the industrial production is facilitated.
5. The membrane is subjected to in-situ reduction by ultraviolet, other reducing agents (such as aldehyde) are not required to be added, the environment is protected, the efficiency is high, the price is low, the reaction condition is mild, and the influence on a desalting layer during reaction is effectively reduced, so that the membrane produced by the scheme has high antibacterial property and good desalting rate and water flux.
Test results show that the reverse osmosis membrane has the initial water flux of more than 45.8gfd and the initial desalination rate of more than 99.48 percent, and after being washed by a raw aqueous solution of escherichia coli for 24 hours, the membrane has the water flux retention rate of more than 91 percent and the desalination rate reduction of less than 0.08 percent, and has excellent water flux, desalination rate and antibacterial scouring resistance.
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.
Example 1
a) Coating a water phase solution on a polysulfone supporting layer of the polysulfone non-woven fabric composite basement membrane, then coating an oil phase solution, and drying at 60 ℃ for 3min to form a polyamide separation layer on the polysulfone supporting layer to obtain a nascent state polyamide reverse osmosis membrane;
wherein,
the aqueous phase solution comprises base liquid and a pH regulator; the base fluid comprises the following components in percentage by mass:
3% of m-phenylenediamine;
1% of sodium dodecyl benzene sulfonate;
8% of dimethyl sulfoxide;
the balance of deionized water.
The pH regulator is NaOH, and the dosage is to ensure that the pH value of the aqueous phase solution is 8.
The oil phase solution comprises the following components in percentage by mass:
0.1 percent of trimesoyl chloride;
the balance of n-hexane.
b) Rinsing the obtained nascent polyamide reverse osmosis membrane, and specifically sequentially carrying out the following rinsing steps:
b1 ) entering a first rinsing tank, and rinsing with deionized water at 20 ℃ for 2min;
b2 Into a second rinse tank, rinsing with an aqueous isopropanol solution (3% strength) at 60 ℃ for 5min;
b3 Into a third rinsing tank, rinsing with 60 deg.C citric acid aqueous solution (concentration 3%) for 5min;
b4 ) entering a fourth rinsing tank, and rinsing with deionized water at 20 ℃ for 2min;
b5 ) was introduced into a fifth rinsing tank and rinsed with an aqueous glycerol solution (3% strength) at 25 ℃ for 5min.
c) Coating the post-treatment solution on the surface of the polyamide separation layer of the obtained rinsing membrane for 3s, removing the redundant solution, treating in an oven at 80 ℃ for 2min, and irradiating for 2min by using a 110W ultraviolet lamp to obtain a composite membrane containing Ag nano particles in a cross-linked PVA structure on the surface;
wherein,
the raw material formula of the post-treatment solution is as follows:
2% of PVA (molecular weight 200000 Da);
1% of sodium dodecyl benzene sulfonate;
8% of chitosan (deacetylation degree is more than 95%);
0.1% of silver nitrate;
the balance of deionized water.
The working-up solution was prepared as follows:
adding deionized water into the high-temperature kettle, turning on a stirring switch, setting the rotating speed at 45r/min, and adding PVA; heating and setting the temperature to 80 ℃, and stirring for more than 2 hours until the materials are completely dissolved; cooling, transferring to a stirring barrel, adding sodium dodecyl benzene sulfonate, chitosan and silver nitrate, and stirring for 30min in the dark to obtain a post-treatment solution.
Comparative example 1
The procedure is as in example 1, except that in step c) no silver nitrate and no chitosan are added to the post-treatment solution used.
Comparative example 2
Carried out as in example 1, except that step c) is adjusted as follows:
c1 Coating PVA solution on the surface of a polyamide separation layer of the obtained rinsing membrane for 3s, removing redundant solution, and treating in an oven at 80 ℃ for 2min to obtain a composite membrane with a cross-linked PVA structure on the surface;
wherein,
the PVA solution has the following raw material formula:
PVA (molecular weight 200000 Da) 2%;
1% of sodium dodecyl benzene sulfonate;
the balance of deionized water.
The preparation process of the PVA solution is as follows: dissolving PVA in deionized water, heating to 80 ℃, stirring until the PVA is completely dissolved, cooling, adding sodium dodecyl benzene sulfonate, stirring and dissolving to obtain a PVA solution.
c2 Coating one side of the obtained composite film with PVA layer and AgNO 3 The aqueous solution (concentration 1 wt%) was contacted for 5min to remove excess solution. Then, the composite membrane is placed into an oven with the temperature of 100 ℃ to be heated for 10min, and the antibacterial composite membrane with the Ag nano particles on the surface is obtained.
Comparative example 3
Carried out as in example 1, except that step c) is adjusted as follows:
c) Coating a PVA solution on the surface of a polyamide separation layer of the obtained rinsing membrane, contacting for 30s, removing redundant solution, and then performing crosslinking treatment in a drying oven at 100 ℃ for 10min to obtain a composite membrane with a crosslinked PVA structure on the surface;
wherein,
the PVA solution includes: base fluid and pH regulator; wherein, the base liquid formula is as follows:
PVA (molecular weight 200000 Da) 2%;
0.1 percent of formaldehyde;
1% of sodium dodecyl benzene sulfonate;
8% of chitosan (degree of deacetylation is more than 95%);
0.1% of silver nitrate;
the balance of deionized water.
The pH adjuster is dilute nitric acid in an amount such that the solution pH =1.
The preparation process of the PVA solution is as follows: adding deionized water into the high-temperature kettle, turning on a stirring switch, setting the rotating speed at 45r/min, and adding PVA; heating and stirring at 90 deg.C until completely dissolved; cooling, transferring to a stirring barrel, adding sodium dodecyl benzene sulfonate, chitosan and silver nitrate, and stirring for 30min in the dark to obtain a base solution. Then, dilute nitric acid was dropwise added with stirring to adjust the pH =1 of the solution, thereby obtaining a PVA solution.
Example 2: product testing
And (3) testing process: putting reverse osmosis membranes into raw water solution containing escherichia coli, soaking and washing for 0h, 3h, 12h and 24h repeatedly, putting the membranes into a membrane pool, removing ionized water for 15min under the conditions of pressure of 1.03MP, temperature of 25 ℃ and membrane surface flow rate of 1.1GPM/min, filtering 1500ppm sodium chloride water solution under the conditions of pressure of 1.03MP, temperature of 25 ℃ and membrane surface flow rate of 1.1GPM/min, and measuring the volume of the permeation solution and the concentration of sodium chloride in the permeation solution.
The water permeability of the reverse osmosis membrane is calculated by the following formula:
j = Q/(A.t), wherein J is water flux, Q is water permeability (L), and A is effective membrane area (m) of the reverse osmosis membrane 2 ) T is time (h);
the salt rejection of the reverse osmosis membrane is calculated by the following formula:
R＝(C p -C f )/C p x 100%, wherein R is the salt rejection, C p Is the concentration of sodium chloride in the stock solution, C f The concentration of sodium chloride in the permeate was used.
The test results are shown in table 1:
table 1: test results of reverse osmosis membranes obtained in example 1 and comparative examples 1 to 3
Note: the retention rate of the water flux of the membrane after 24h of washing is = (the water flux of the membrane after 24h of washing is divided by the water flux of the initial membrane) x 100%. The decrease in membrane rejection after 24h of scour = initial membrane rejection-membrane rejection after 24h of scour.
As can be seen from the test results in Table 1, the antibacterial composite membrane obtained in example 1 of the invention has an initial water flux of 45.8gfd and an initial salt rejection of 99.48%, and after being washed by a raw aqueous solution of Escherichia coli for 24 hours, the water flux retention rate of the membrane can still reach 92%, and the salt rejection reduction amount is only 0.08%, so that the antibacterial composite membrane has excellent water flux, salt rejection and antibacterial wash resistance. As can be seen from comparison between example 1 and comparative example 1, if silver nitrate and chitosan are not added to the PVA coating solution (i.e., the post-treatment solution), but the membrane is severely degraded in performance after being washed and polluted by the bacteria-containing solution, and has weak antibacterial property and is not resistant to washing. As can be seen from the comparison between the embodiment 1 and the comparative example 2, the ultraviolet reduction method is adopted, the conditions are milder, only one heat treatment is needed for preparing the antibacterial layer, the influence on the desalting layer is small, and the membrane has excellent antibacterial performance and good water flux and desalting rate. As can be seen from the comparison between the example 1 and the comparative example 3, the invention adopts a certain post-treatment fluid formula and combines an ultraviolet reduction method, does not need to add other reducing agents (such as aldehyde), is green and environment-friendly, has milder reaction conditions, effectively reduces the influence on a desalting layer during reaction, has excellent antibacterial performance and has better membrane water flux and desalting rate.
Example 3
The procedure is as in example 1, except that in step c), the heat treatment temperature is 60 ℃ and the UV lamp power is 180W.
Example 4
The procedure is as in example 1, except that in step c) the temperature of the heat treatment is 90 ℃ and the UV lamp power is 80W.
Example 5
The procedure is as in example 1, except that in step a) the polyfunctional amine in the aqueous solution is replaced by ethylenediamine and the aromatic acid chloride monomer in the oily solution is replaced by isophthaloyl dichloride.
Example 6
The procedure is as in example 1, except that in step c), the starting formulation of the post-treatment solution is as follows:
2% of PVA (molecular weight 200000 Da);
1% of sodium dodecyl benzene sulfonate;
chitosan (degree of deacetylation > 95%) 30%;
8% of silver nitrate;
the balance of deionized water.
Example 7: product testing
The reverse osmosis membranes obtained in examples 3 to 6 were tested according to the test method in example 2, and the results are shown in Table 2.
Table 2: test results of reverse osmosis membranes obtained in examples 3 to 6
As can be seen from the test results in tables 1-2, the reverse osmosis membranes obtained in examples 1,3-6 of the present invention have an initial water flux of 45.8gfd or more and an initial salt rejection of 99.48% or more, and after being washed with a raw aqueous solution of Escherichia coli for 24 hours, the membrane has a water flux retention rate of 91% or more and a salt rejection reduction of 0.08% or less, and have excellent water flux, salt rejection and antibacterial wash resistance.
The foregoing examples are included merely to facilitate an understanding of the principles of the invention and their core concepts, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, it is possible to make various improvements and modifications to the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that approximate the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (10)
1. The preparation method of the efficient bacteriostatic anti-pollution reverse osmosis membrane is characterized by comprising the following steps of:
a) Coating a water phase solution on a polysulfone supporting layer of a base membrane, then coating an oil phase solution and drying to form a polyamide separation layer on the polysulfone supporting layer so as to obtain a nascent state polyamide reverse osmosis membrane;
wherein,
the aqueous phase solution comprises a base solution and a pH regulator; the base fluid comprises the following components in percentage by mass:
0.5% -5% of polyfunctional amine;
0.05% -2% of a surfactant;
3% -10% of a polar solvent;
the balance of water;
the oil phase solution comprises the following components in percentage by mass:
0.05% -0.3% of polyfunctional acyl halide;
the balance of organic solvent;
b) Rinsing the nascent polyamide reverse osmosis membrane to obtain a rinsed membrane;
c) Coating the post-treatment solution on the surface of the polyamide separation layer of the rinsing membrane, and then carrying out heat treatment and ultraviolet irradiation treatment to obtain the efficient bacteriostatic anti-pollution reverse osmosis membrane;
wherein,
the post-treatment solution comprises the following components in percentage by mass:
1% -3% of polyvinyl alcohol;
0.05% -2% of a surfactant;
5% -30% of chitosan;
0.05 to 8 percent of silver nitrate
The balance of water.
2. The method according to claim 1, wherein the molecular weight of the polyvinyl alcohol in step c) is 150000 to 300000da.
3. The method according to claim 1, wherein in step c), the heat treatment is carried out under the following conditions: 60 to 90 ℃ for 2 to 8min.
4. The method according to claim 1, wherein in step c), the conditions of the ultraviolet irradiation treatment are: the power of an ultraviolet lamp is 80 to 180W, and the irradiation time is 2 to 8min.
5. The method of claim 1, wherein in step a):
in the aqueous phase solution, the pH regulator is an alkaline regulator;
the dosage of the pH regulator is that the pH value of the aqueous phase solution reaches 7 to 9;
the polyfunctional amine is at least one of aromatic amine, aliphatic amine and alicyclic amine;
the polyfunctional acyl halide is an aromatic acyl chloride monomer.
6. The production method according to claim 1 or 5, characterized in that the polyfunctional amine is at least one of m-phenylenediamine, ethylenediamine, propylenediamine, butylenediamine, hexylenediamine, N- (2-hydroxyethyl) ethylenediamine, 1, 2-diaminocyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, diethylenetriamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, sym-benzenetriamine, piperazine, and 4-aminomethylpiperazine;
the multifunctional acyl halide is at least one of trimesoyl chloride, phthaloyl chloride, isophthaloyl chloride and terephthaloyl chloride.
7. The method of claim 1, wherein in step a):
the polar solvent is dimethyl sulfoxide and/or N-methylpyrrolidone;
the organic solvent is at least one of n-hexane, isopar G and Isopar L.
8. The method according to claim 1, wherein in step b), the rinsing comprises sequentially performing the following rinsing steps:
b1 Rinsing with deionized water;
b2 Rinsing with an aqueous isopropyl alcohol solution;
b3 Rinsing with an aqueous citric acid solution;
b4 Rinsing with deionized water);
b5 Using an aqueous glycerol solution.
9. The preparation method of claim 8, wherein in the step b 1), the temperature of deionized water is 15 to 30 ℃, and the rinsing time is 1 to 5min;
in the step b 2), the mass percentage concentration of the isopropanol aqueous solution is 1% -5%, the temperature of the isopropanol aqueous solution is 50-80 ℃, and the rinsing time is 2-10 min;
in the step b 3), the mass percentage concentration of the citric acid aqueous solution is 1-5%, the temperature of the citric acid aqueous solution is 50-80 ℃, and the rinsing time is 2-10 min;
in the step b 4), the temperature of deionized water is 15 to 30 ℃, and the rinsing time is 1 to 5min;
in the step b 5), the mass percentage concentration of the glycerol aqueous solution is 2% -6%, the temperature of the glycerol aqueous solution is 15-30 ℃, and the rinsing time is 2-10 min.
10. An efficient bacteriostatic anti-pollution reverse osmosis membrane prepared by the preparation method of any one of claims 1-9.
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| CN117160254A (en) * | 2023-10-31 | 2023-12-05 | 湖南沁森高科新材料有限公司 | Reverse osmosis composite membrane and preparation method thereof |
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