Antibacterial anti-biological pollution reverse osmosis composite membrane and preparation method thereof

Abstract

The invention provides an antibacterial and anti-biological-pollution reverse osmosis composite membrane and a preparation method thereof, and belongs to the technical field of water treatment equipment, the antibacterial and anti-biological-pollution reverse osmosis composite membrane comprises a non-woven fabric supporting layer, and the non-woven fabric supporting layer is provided with a high-molecular polymer porous layer and a polyamide desalination layer containing an amide functional group bactericide; wherein the polyamide desalination layer is formed by interfacial polymerization of polyamine and polyacyl chloride. The desalting layer contains an amide bactericide and contains an amide functional group, so that the problem that an antibacterial agent is separated out from the desalting layer can be reduced, and the long-term stability of the antibacterial property is improved; the interfacial tension between the amide bactericide and the polyamide is low, a uniform and stable microstructure is easily formed, the amide bactericide and the polyamide are tightly combined with the desalination layer, the uniform and stable microstructure is formed, the internal defects are few, and the desalination rate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment equipment, and particularly relates to an antibacterial and antibiofouling reverse osmosis composite membrane and a preparation method thereof. BACKGROUND

[0002] The reverse osmosis membrane has poor antibacterial and antibiofouling performance. Biofouling of a reverse osmosis system refers to the phenomenon that microorganisms (such as bacteria, algae, fungi, etc.) reproduce on the surface or inside of the membrane to form a biofilm, thereby reducing the system efficiency or even damaging the membrane element.

[0003] The reverse osmosis membrane technology has outstanding advantages such as low energy consumption and high efficiency, and is one of the most widely used separation technologies. However, the reverse osmosis membrane still has the problem of poor anti-fouling ability in actual operation and operation process, especially bacteria and other microorganisms can adsorb and reproduce on the membrane surface, and secrete extracellular polymers to form a dense biofilm, which causes serious performance degradation of the reverse osmosis membrane.

[0004] Chinese patent application with application number 2013103390654 and 2012100070306 discloses that a layer of antibacterial material is coated on the surface of the reverse osmosis membrane to inhibit microorganisms. However, this method has limitations: the antibacterial material is easy to fall off in the long-term operation process, which reduces the long-term effectiveness of the antibiofouling, and the falling material may even cause secondary pollution to the membrane. Chinese patents with authorization announcement numbers CN112473398B, CN112827368B and CN115228291B use a chemical post-treatment method to graft the antibacterial material on the surface of the reverse osmosis membrane. This method needs a modified substance with high chemical reaction activity and complex structure, and the preparation process is complex and the cost is high. Chinese patent applications with announcement numbers CN106621832A and CN110449042A prepare an antibiofouling reverse osmosis membrane by adding antibacterial additives in the aqueous phase and the organic phase. The physical and chemical properties of these additive materials are different from those of the desalination layer polyamide material, and the compatibility between them is poor, the interface bonding force is weak, and defects are easy to occur. SUMMARY

[0005] The present application aims to provide an antibacterial and antibiofouling reverse osmosis composite membrane and a preparation method thereof, to solve at least one of the technical problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides an anti-bacterial and anti-biofouling reverse osmosis composite membrane, comprising a non-woven support layer, a high polymer porous layer and a polyamide desalination layer containing an amide functional group bactericide on the non-woven support layer; wherein the polyamide desalination layer is formed by interfacial polymerization of a polyamine and a polyacyl chloride.

[0008] As a further limitation of the first aspect of the present application, the high polymer porous layer material is polysulfone, polyether sulfone, polyvinylidene fluoride, polyethylene or polypropylene.

[0009] As a further limitation of the first aspect of the present application, the polyamide desalination layer is formed by interfacial polymerization of piperazine and trimesoyl chloride.

[0010] As a further limitation of the first aspect of the present application, the polyamide desalination layer is formed by interfacial polymerization of m-phenylenediamine and trimesoyl chloride.

[0011] In a second aspect, the present application provides a method for preparing an anti-bacterial and anti-biofouling reverse osmosis composite membrane, comprising the following steps: preparing a high polymer porous layer on a non-woven support layer by the immersion precipitation method to form a composite support layer; immersing the composite support layer in an amine monomer aqueous solution of a certain concentration, which contains a bactericide with an amide functional group at a certain concentration; taking out the composite support layer, draining the surface water, and then coating the surface with an oil phase solution; preparing a raw membrane sheet after drying; and cleaning the raw membrane sheet with a sodium carbonate solution to wash away the residual polyamine and polyacyl chloride, thereby obtaining the anti-bacterial and anti-biofouling reverse osmosis composite membrane.

[0012] As a further limitation of the second aspect of the present application, the amine monomer is piperazine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, polyethyleneimine, benzylamine, 2,5-diaminobenzenesulfonic acid or aliphatic diamine.

[0013] As a further limitation of the second aspect of the present application, the bactericide contains an amide functional group in its structure.

[0014] As a further limitation of the second aspect of the present application, the bactericide is a bactericide containing an amide functional group, such as erucamide, fenhexamid, thifluzamide, pyridine fungicide amide, etc.

[0015] As a further limitation of the second aspect of the present application, the oil phase monomer is trimesoyl chloride, and the concentration range is 0.1wt%~2wt%.

[0016] As a further limitation of the second aspect of the present application, the oil phase solvent is Isopar series solvent, cyclohexane, n-hexane or n-heptane.

[0017] The application has the advantages that: the desalination layer contains a new type of antibacterial and anti-pollution modified material: amide bactericide, the amide bactericide contains amide functional groups, which are similar to the molecular structure of the reverse osmosis polyamide desalination layer, the intermolecular forces are similar and strong, which can reduce the problems such as precipitation of the antibacterial agent from the desalination layer, and improve the long-term stability of the antibacterial performance; the interface tension between the amide bactericide and the polyamide is low, and a uniform and stable microstructure can be easily formed, which is combined with the desalination layer very closely, a uniform and stable microstructure can be formed, and the internal defects are few, which is beneficial to the desalination rate of the reverse osmosis membrane.

[0018] The advantages of the additional aspects of the application will become more apparent in the light of the following description, or will be understood by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0020] Figure 1 The antibacterial and anti-biological pollution reverse osmosis membrane structure described in the embodiments of the application is shown in the schematic diagram.

[0021] Figure 2 The bactericide structure containing amide functional groups described in the embodiments of the application is shown in the schematic diagram. DETAILED DESCRIPTION

[0022] The embodiments of the application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with the drawings are exemplary and are only used to explain the application, and cannot be interpreted as a limitation on the application.

[0023] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the field of the application.

[0024] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as such.

[0025] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It is further understood that the terms "comprising," "including," "containing," and "having" and the like, when used in the specification, specify the presence of stated features, integers, steps, operations, elements, and / or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0026] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Those skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0027] In order to facilitate the understanding of the present application, the present application will be further explained and described in specific embodiments in connection with the accompanying drawings, and the specific embodiments do not constitute a limitation on the embodiments of the present application.

[0028] Those skilled in the art should understand that the drawings are only schematic of the embodiments, and the components in the drawings are not necessarily essential for the implementation of the present application.

[0029] In view of the poor antibacterial and anti-biofouling performance of existing reverse osmosis membranes, the poor compatibility of antibacterial modified materials with reverse osmosis membrane materials, the weak interfacial bonding force, and the easy defects, the present application aims to provide a high-efficiency and stable antibacterial and anti-biofouling reverse osmosis membrane. The second purpose is to provide a preparation method of an antibacterial and anti-biofouling reverse osmosis membrane with simple process and easy scale production.

[0030] In this embodiment, an antibacterial and anti-biofouling reverse osmosis membrane is provided, as shown in Figure 1 The non-woven fabric support layer mainly plays a supporting role. The material of the high molecular polymer porous layer includes but is not limited to polysulfone, polyether sulfone, polyvinylidene fluoride, polyethylene, polypropylene, etc., which can be ultrafiltration membrane or microfiltration membrane, preferably ultrafiltration membrane. The polyamide desalination layer is formed by interfacial polymerization of polyamine and polyacyl chloride, preferably piperazine and trimesoyl chloride or m-phenylenediamine and trimesoyl chloride.

[0031] In this embodiment, a simple and easily mass-producible method for preparing antibacterial and anti-biofouling reverse osmosis membrane is also provided. The process technology is as follows: (1) A porous polymer layer is prepared on the non-woven fabric support layer by immersion precipitation to form a composite support layer.

[0032] (2) The above composite support layer is immersed in an aqueous solution of amine monomers of a certain concentration and contains a bactericide with amide functional groups of a certain concentration.

[0033] The amine monomer includes, but is not limited to, at least one of piperazine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, polyethyleneimine, benzylamine, 2,5-diaminobenzenesulfonic acid, and aliphatic diamines, with a concentration of 0.1 wt% to 20 wt%. Preferably, the amine monomer is m-phenylenediamine, and preferably, its concentration is 2 to 4 wt%.

[0034] The bactericide contains amide functional groups in its structure, including but not limited to benzamides, pyridineamides, thiazolylamides, etc., with structures such as... Figure 2 In the diagram, X: is typically a methoxy group (—OCH3); R: an alkyl or aryl group; R 1 : Halogen, trifluoromethyl and other substituents; R 2 Ar¹ group: benzene ring, heterocyclic ring or other aromatic group; Ar¹ group: benzene ring (monosubstituted or polysubstituted).

[0035] In this embodiment, the bactericide is preferably erucamide, with a preferred concentration of 2-4%.

[0036] The pH range of the aqueous solution can be 7 to 12; preferably, the pH is 10 to 11.

[0037] (3) Remove the composite support layer, drain the water droplets from the surface, and then coat the surface with an oil phase solution.

[0038] The oil phase solution comprises an oil phase solvent and an oil phase monomer.

[0039] The oil phase solvent includes, but is not limited to, Isopar series solvents, cyclohexane, n-hexane, n-decane, etc. n-Hexane is preferred.

[0040] The oil phase monomer is pyromellitic trimethylolpropionate chloride, with a concentration ranging from 0.1 wt% to 2 wt%, preferably from 0.1% to 0.3%.

[0041] (4) After drying in a 90℃ oven for 5 min, the original membrane was prepared.

[0042] (5) The original membrane is cleaned with sodium carbonate solution to remove residual polyamines and polyacrylamide chlorides.

[0043] The novel antibacterial and antifouling reverse osmosis membrane proposed in this embodiment contains a novel antibacterial and antifouling modified material in its desalination layer: an amide-based bactericide. Compared with existing antibacterial and antifouling modified materials, such as bactericidal nanomaterials (silver, copper, titanium dioxide, graphene oxide, etc.) and quaternary ammonium salts, the amide-based bactericide contains amide functional groups, which are similar to the molecular structure of the reverse osmosis polyamide desalination layer. The similar molecular structure and strong intermolecular forces reduce problems such as the precipitation of antibacterial agents from the desalination layer, improving the long-term stability of antibacterial performance. The low interfacial tension between the amide-based bactericide and the polyamide facilitates the formation of a uniform and stable microstructure, resulting in a very tight bond with the desalination layer. This leads to a uniform and stable microstructure with fewer internal defects, which is beneficial to the desalination rate of the reverse osmosis membrane.

[0044] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. An antibacterial and anti-biofouling reverse osmosis composite membrane, comprising a nonwoven fabric support layer, characterized in that: The nonwoven fabric support layer is provided with a porous polymer layer and a polyamide desalination layer containing a bactericide with amide functional groups; wherein, the polyamide desalination layer is formed by interfacial polymerization of polyamines and polyacryl chlorides.

2. The antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 1, characterized in that: The porous polymer layer is made of polysulfone, polyethersulfone, polyvinylidene fluoride, polyethylene, or polypropylene.

3. The antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 1, characterized in that: The polyamide desalting layer is formed by interfacial polymerization of piperazine and pyromellitic trimethylol chloride.

4. The antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 1, characterized in that: The polyamide desalting layer is formed by interfacial polymerization of m-phenylenediamine and trimesoyl chloride.

5. A method for preparing an antibacterial and anti-biofouling reverse osmosis composite membrane, characterized in that, The process includes the following steps: a porous polymer layer is prepared on a nonwoven support layer by immersion precipitation to form a composite support layer; the composite support layer is immersed in an aqueous solution of amine monomers of a certain concentration, the aqueous solution of amine monomers containing a certain concentration of bactericides with amide functional groups; the composite support layer is removed, the surface water droplets are drained, and an oil phase solution is coated on the surface; after drying, a virgin membrane is prepared; the virgin membrane is cleaned with sodium carbonate solution to wash away residual polyamines and polyacrylamide chlorides, thus obtaining the antibacterial and anti-biofouling reverse osmosis composite membrane.

6. The method for preparing the antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 5, characterized in that, The amine monomer is piperazine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, polyethyleneimine, benzylamine, 2,5-diaminobenzenesulfonic acid, or an aliphatic diamine.

7. The method for preparing the antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 5, characterized in that, The bactericide contains amide functional groups in its structure.

8. The method for preparing the antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 7, characterized in that, The fungicides are erucamide, benzyme, thifluzamide, or pyridabenamide.

9. The method for preparing an antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 5, characterized in that, The oil phase monomer is pyromellitic trimethylol chloride, with a concentration range of 0.1wt% to 2wt%.

10. The method for preparing an antibacterial and anti-biofouling reverse osmosis composite membrane according to claim 5, characterized in that, The oil phase solvent is an Isopar series solvent, cyclohexane, n-hexane, or n-decane.

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