A reverse osmosis membrane and a preparation method and application thereof

Abstract

The application provides a reverse osmosis membrane and a preparation method and application thereof. The preparation method comprises the following steps: (1) polymeric reaction of a polyamine and a polyacyl chloride on a support membrane to form a polyamide layer on the support membrane; and (2) reaction of the polyamide layer prepared in step (1) and a benzene series A to obtain the reverse osmosis membrane; the benzene series A is a benzene series containing an amino group, an antibacterial group, a disulfide bond and a phenoxy group. The reverse osmosis membrane provided by the application has high flux and high desalination rate, and excellent oxidation resistance, antibacterial property and acid and alkali resistance.

Description

TECHNICAL FIELD

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

[0002] With the development of society, water resource shortage has become a global problem to be solved urgently, and existing water resources, especially fresh water resources, have been unable to meet the development needs of society and economy. Efficient water resource recovery and utilization has become a hot issue. Membrane water treatment has advantages of low energy consumption, high efficiency, no by-products, and continuous operation, and has broad development prospects in the fields of municipal sewage, domestic sewage, industrial wastewater, and various industries.

[0003] Looking at the current market, most reverse osmosis membranes are aromatic polyamide structure composite membranes. A nanoscale polyamide functional layer is obtained on the surface of a polyester non-woven fabric and a polysulfone support layer through an interfacial condensation reaction of m-phenylenediamine and benzene tricarboxylic chloride. However, in the process of wide application, a series of problems still hinder the application and development of reverse osmosis membranes in the water treatment industry.

[0004] As known, pollution inevitably occurs in industrial application scenarios, and membrane pollution is divided into organic pollution, non-polar pollution, and microbial pollution. Microbial pollution is the most troublesome. By adding an appropriate amount of sodium hypochlorite and other active chlorine in the raw material to kill bacteria, a certain inhibitory effect on microbial pollution can be achieved. However, the three-dimensional network structure of polyamide itself is not resistant to oxidation, and is extremely susceptible to attack by active chlorine and degradation. Moreover, the irreversible damage risk of residual chlorine to reverse osmosis membranes seriously affects the stability and service life of reverse osmosis membranes in operation, and greatly increases the operation cost. Therefore, it is extremely important to simultaneously control biological pollution and improve the oxidation resistance of reverse osmosis membranes.

[0005] In order to solve the above problems, various methods for preparing oxidation-resistant and antibacterial reverse osmosis membranes have been disclosed. CN113522065A discloses a chlorine-resistant and pollution-resistant polyamide reverse osmosis composite membrane and a preparation method thereof. The chlorine-resistant and pollution-resistant polyamide reverse osmosis composite membrane comprises a base film, a polyamide reverse osmosis membrane formed on the base film, and a protective layer formed on the polyamide reverse osmosis membrane. The protective layer is formed of 3-(trimethoxysilyl) propyl acrylate-co-polyethylene glycol methyl ether methacrylate copolymer and deposited on the surface of the polyamide reverse osmosis membrane through a chemical grafting reaction. In the protective layer, the 3-(trimethoxysilyl) propyl acrylate-co-polyethylene glycol methyl ether methacrylate copolymer forms a three-dimensional polymer network structure through a hydrolysis and condensation reaction. The protective layer formed of 3-(trimethoxysilyl) propyl acrylate-co-polyethylene glycol methyl ether methacrylate copolymer and deposited through a chemical grafting reaction achieves the purposes of chlorine resistance and pollution resistance.

[0006] CN115155315A discloses a high-performance antibacterial reverse osmosis membrane and a preparation method thereof, the preparation method comprising the following steps: uniformly coating a casting solution on a non-woven fabric, then placing it in a pure water coagulation bath, allowing the casting solution to solidify on the non-woven fabric to obtain a base film; dispersing silver nanowires in pure water to prepare a silver nanowire dispersion; uniformly coating the silver nanowire dispersion on the base film and drying for a certain time to form a base film with a silver nanowire layer; dissolving m-phenylenediamine in water to prepare an aqueous phase solution, mixing trimesoyl chloride and n-hexane to prepare an oil phase solution; the aqueous phase solution and the oil phase solution undergo a polymerization reaction on the base film with the silver nanowire layer to obtain an antibacterial reverse osmosis membrane. The technical solution achieves the purpose of long-term antibiosis by adding a silver nanowire layer.

[0007] Although the above-mentioned patent can make certain improvements in oxidation resistance and antibiosis, it still cannot simultaneously have the properties of oxidation resistance and antibiosis without losing the basic properties of the reverse osmosis membrane.

[0008] Therefore, it is necessary to develop an oxidation-resistant and antibacterial high-flux reverse osmosis membrane. SUMMARY

[0009] In view of the deficiencies of the prior art, the purpose of the present application is to provide a reverse osmosis membrane and a preparation method and application thereof. By modifying the polyamide layer with a benzene series containing amino groups, antibacterial groups, disulfide bonds and phenoxy groups, the prepared reverse osmosis membrane has high flux, high desalination rate, excellent oxidation resistance and antibiosis, and still maintains good performance after acid and alkali cleaning.

[0010] To achieve this purpose, the present application adopts the following technical solutions:

[0011] In a first aspect, the present application provides a preparation method of a reverse osmosis membrane, the preparation method comprising the following steps:

[0012] (1) polyamine and polyacyl chloride are subjected to a polymerization reaction on a support membrane to form a polyamide layer on the support membrane;

[0013] (2) the polyamide layer prepared in step (1) is reacted with a benzene series A to obtain the reverse osmosis membrane;

[0014] The benzene series A is a benzene series containing amino groups, antibacterial groups, disulfide bonds and phenoxy groups.

[0015] In the present application, the amino group in the benzene A can react with the acyl chloride group remaining on the surface of the polyamide layer to form an amide bond, thereby grafting and fixing the benzene A to the surface of the polyamide layer through a chemical bond. The antibacterial group can significantly improve the antibacterial performance of the reverse osmosis membrane, effectively preventing the occurrence of biological pollution. On the other hand, the disulfide bond can effectively improve the chlorine resistance of the polyamide layer. The disulfide bond has lower bond energy than the amide bond. By introducing the disulfide bond into the polyamide molecular backbone, the characteristics of the disulfide bond are stronger than the amide bond in redox activity. When the reverse osmosis membrane contacts chlorine, it is preferentially oxidized and forms a stable group, thereby protecting the amide bond. In addition, the disulfide bond introduced by benzene A is relatively stable under acid and alkali cleaning conditions, so that the reverse osmosis membrane can still maintain good oxidation resistance and antibacterial performance after acid and alkali cleaning.

[0016] Preferably, the antibacterial group comprises an indole group and / or a pyridine group.

[0017] Preferably, the benzene A contains at least one amino group, at least one indole group or pyridine group, at least one disulfide bond, and at least one phenoxy group.

[0018] Preferably, the benzene A comprises 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene and / or 2,2'-(2-pyridyl)-6,6'-amino-7,7'-phenoxy-disulfide benzene.

[0019] Preferably, the reaction in step (2) further comprises reacting with benzene B, which is a benzene containing a thiol group and a carboxyl group.

[0020] Preferably, the reaction with benzene B is carried out in the presence of dimethyl sulfoxide.

[0021] In the present application, the amino group in the benzene A can react with the acyl chloride group remaining on the surface of the polyamide layer to form an amide bond, thereby grafting and fixing the benzene A to the surface of the polyamide layer through a chemical bond. When contacted with benzene B, the disulfide bond in benzene A and the thiol group in benzene B undergo a coupling reaction under the oxidation of dimethyl sulfoxide, forming a reaction product of benzene A and benzene B, which is a benzene containing an amino group, a disulfide bond, an antibacterial group, a carboxyl group, and a phenoxy group. The preparation method of the present application can graft benzene A and benzene B to the surface of the polyamide layer without adding additional cross-linking agents.

[0022] In the present application, the reaction with the benzene B can introduce carboxyl and phenoxy with strong hydrophilicity on the surface of the reverse osmosis membrane, which can increase the membrane flux to a certain extent. After the interfacial polymerization reaction is completed, the benzene A and the benzene B are grafted, which can ensure that the crosslinking degree of the polyamide layer formed in the interfacial polymerization reaction process is not affected, and the newly formed amide bond can increase the dense structure of the reverse osmosis membrane to a certain extent, thereby ensuring that the desalination rate is not affected.

[0023] Preferably, the benzene B contains at least one thiol group and at least one carboxyl group.

[0024] Preferably, the benzene B includes any one or a combination of at least two of 3-amino-4-mercaptobenzoic acid, 5-fluoro-2-mercaptobenzoic acid, or 3-mercaptobenzoic acid.

[0025] Preferably, the support membrane includes a non-woven fabric support layer and a polysulfone layer.

[0026] Preferably, the polyamine includes m-phenylenediamine.

[0027] Preferably, the polyacyl chloride includes trimesoyl chloride.

[0028] Preferably, the polyamide layer includes aromatic polyamide with a three-dimensional network structure formed by interfacial polymerization of m-phenylenediamine and trimesoyl chloride.

[0029] Preferably, step (1) specifically includes the following steps: after the support membrane is first contacted with an aqueous solution of polyamine, it is secondly contacted with an organic solution of polyacyl chloride, so that the polyacyl chloride and the polyamine undergo a polymerization reaction to obtain a polyamide layer.

[0030] In the present application, the polyamide layer is formed by interfacial polymerization of polyamine and polyacyl chloride.

[0031] Preferably, the aqueous solution of polyamine includes polyamine and water.

[0032] Preferably, the concentration of polyamine in the aqueous solution of polyamine is 1.0wt% to 3.0wt%, such as 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2.0wt%, 2.2wt%, 2.4wt%, 2.6wt%, 2.8wt%, etc.

[0033] Preferably, the organic solution of polyacyl chloride includes polyacyl chloride and an organic solvent.

[0034] Preferably, the concentration of the polybasic acid chloride in the organic solution of the polybasic acid chloride is 0.08wt% to 0.2wt%, such as 0.09wt%, 0.10wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt%, 0.16wt%, 0.17wt%, 0.18wt% or 0.19wt% and the like.

[0035] Preferably, the organic solvent comprises any one or a combination of at least two of aliphatic alkane, aromatic alkane or halogenated alkane, further preferably aliphatic alkane.

[0036] Preferably, the aliphatic alkane comprises any one or a combination of at least two of n-decane, isopar G isomeric alkane, isopar L isomeric alkane or isopar H isomeric alkane.

[0037] Preferably, the temperature of the first contacting in step (1) is 20 to 30℃ (such as 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃ or 29℃ and the like), and the time is 10 to 300s (such as 30s, 60s, 90s, 120s, 150s, 180s, 210s, 240s or 270s and the like), further preferably 30 to 60s.

[0038] Preferably, the temperature of the second contacting in step (1) is 20 to 30℃ (such as 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃ or 29℃ and the like), and the time is 10 to 300s (such as 30s, 60s, 90s, 120s, 150s, 180s, 210s, 240s or 270s and the like), further preferably 30 to 60s.

[0039] Preferably, after the polymerization reaction in step (1), the method further comprises the steps of removing the excess organic solution of the polybasic acid chloride, water washing and drying.

[0040] Preferably, the temperature of the water washing in step (1) is 60 to 90℃ (such as 63℃, 66℃, 69℃, 72℃, 75℃, 78℃, 81℃, 84℃, 86℃ or 89℃ and the like).

[0041] In the present application, after the interfacial polymerization reaction of the polybasic amine and the polybasic acid chloride, the water washing can hydrolyze the residual acyl chloride groups on the surface into carboxyl groups, which can increase the membrane flux to a certain extent.

[0042] Preferably, the temperature of the drying in step (1) is 60 to 90℃ (such as 63℃, 66℃, 69℃, 72℃, 75℃, 78℃, 81℃, 84℃, 86℃ or 89℃ and the like).

[0043] Preferably, the step (2) specifically comprises the following steps:

[0044] The step (2) specifically comprises the following steps: the polyamide layer prepared in step (1) is contacted with solution A, first heat treatment, second heat treatment, a benzene A modified layer is formed on the polyamide layer, and then contacted with solution B, third heat treatment, fourth heat treatment, a benzene A and benzene B modified layer is formed, and the reverse osmosis membrane is obtained.

[0045] The solution A comprises benzene A and water.

[0046] The solution B comprises benzene B, dimethyl sulfoxide and water.

[0047] In the present application, the benzene A and benzene B modified layer comprises benzene A grafted on the polyamide layer, benzene A not grafted on the polyamide layer, benzene B grafted on the polyamide layer, benzene B not grafted on the polyamide layer, reaction products of benzene A and benzene B grafted on the polyamide layer, and reaction products of benzene A and benzene B not grafted on the polyamide layer. Among them, benzene A contains amino groups, disulfide bonds, phenoxy groups and indole groups and / or pyridine groups, benzene B contains thiol groups and carboxyl groups, and the reaction products of benzene A and benzene B contain amino groups, disulfide bonds, carboxyl groups, phenoxy groups and indole groups and / or pyridine groups.

[0048] Preferably, the concentration of benzene A in the solution A is 0.01wt% to 1wt% (such as 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt% or 0.9wt% and the like), and further preferably 0.1wt% to 0.5wt%.

[0049] Preferably, the concentration of benzene B in the solution B is 0.02wt% to 2wt% (such as 0.2wt%, 0.4wt%, 0.6wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.4wt%, 1.6wt% or 1.8wt% and the like), and further preferably 0.2wt% to 1.0wt%.

[0050] Preferably, the concentration of dimethyl sulfoxide in the solution B is 5wt% to 25wt% (such as 7wt%, 9wt%, 11wt%, 13wt%, 15wt%, 17wt%, 19wt%, 21wt% or 23wt% and the like), and further preferably 8wt% to 12wt%.

[0051] Preferably, the first contact of step (2) is for a time period of 10-1200 s (e.g. 100 s, 200 s, 300 s, 400 s, 500 s, 600 s, 700 s, 800 s, 900 s, 1000 s, or 1100 s, etc.), preferably 30-300 s.

[0052] Preferably, step (2) further comprises a step of removing excess solution A before the first heat treatment.

[0053] Preferably, step (2) further comprises a step of water washing after the first heat treatment, at a temperature of 60-90 °C (e.g. 63 °C, 66 °C, 69 °C, 72 °C, 75 °C, 78 °C, 81 °C, 84 °C, 86 °C, or 89 °C, etc.).

[0054] Preferably, the first heat treatment of step (2) is at a temperature of 60-100 °C (e.g. 63 °C, 66 °C, 69 °C, 72 °C, 75 °C, 78 °C, 81 °C, 84 °C, 86 °C, 89 °C, 92 °C, 95 °C, or 98 °C, etc.), further preferably 80-90 °C, for a time period of 0.5-10 min (e.g. 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, or 9 min, etc.), further preferably 1-3 min.

[0055] Preferably, the second heat treatment of step (2) is at a temperature of 60-100 °C (e.g. 63 °C, 66 °C, 69 °C, 72 °C, 75 °C, 78 °C, 81 °C, 84 °C, 86 °C, 89 °C, 92 °C, 95 °C, or 98 °C, etc.), further preferably 80-90 °C, for a time period of 0.5-10 min (e.g. 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, or 9 min, etc.), further preferably 3-6 min.

[0056] Preferably, the second contact of step (2) is for a time period of 10-1200 s (e.g. 100 s, 200 s, 300 s, 400 s, 500 s, 600 s, 700 s, 800 s, 900 s, 1000 s, or 1100 s, etc.), preferably 30-300 s.

[0057] Preferably, step (2) further comprises a step of removing excess solution B before the third heat treatment.

[0058] Preferably, step (2) further comprises a step of water washing after the third heat treatment, at a temperature of 60-90 °C (e.g. 63 °C, 66 °C, 69 °C, 72 °C, 75 °C, 78 °C, 81 °C, 84 °C, 86 °C, or 89 °C, etc.).

[0059] Preferably, the temperature of the third heat treatment in step (2) is 60-100℃ (for example, 63℃, 66℃, 69℃, 72℃, 75℃, 78℃, 81℃, 84℃, 86℃, 89℃, 92℃, 95℃ or 98℃, etc.), further preferably 80-90℃, and the time is 0.5-10min (for example, 1min, 2min, 3min, 4min, 5min, 6min, 7min, 8min or 9min, etc.), further preferably 1-3min.

[0060] Preferably, the temperature of the fourth heat treatment in step (2) is 60-100℃ (for example, 63℃, 66℃, 69℃, 72℃, 75℃, 78℃, 81℃, 84℃, 86℃, 89℃, 92℃, 95℃ or 98℃, etc.), further preferably 80-90℃, and the time is 0.5-10min (for example, 1min, 2min, 3min, 4min, 5min, 6min, 7min, 8min or 9min, etc.), further preferably 3-6min.

[0061] In a second aspect, the present application provides a reverse osmosis membrane prepared by the method of the first aspect.

[0062] In a third aspect, the present application provides use of the reverse osmosis membrane of the second aspect in a water treatment assembly or a water treatment method.

[0063] Compared with the prior art, the present application has the following beneficial effects:

[0064] In the present application, a polyamide layer is formed on a support membrane, and the polyamide layer is modified by a benzene compound containing an amino group, an antibacterial group, a disulfide bond and a phenoxy group, so that an antibacterial group, a disulfide bond and a phenoxy group are introduced on the surface of the reverse osmosis membrane. When contacted with chlorine, the disulfide bond is preferentially oxidized and forms a stable group, thereby protecting the amide bond. The hydrophilic property of the phenoxy group increases the flux. The antibacterial group can provide antibacterial property, and the introduced disulfide bond is relatively stable under acid and alkali cleaning conditions, so that the reverse osmosis membrane can still maintain good oxidation resistance and antibacterial property after acid and alkali cleaning. The reverse osmosis membrane can maintain good performance after acid and alkali cleaning under the premise of ensuring high flux and high desalination rate, and forms a reverse osmosis membrane with large flux, antibacterial property and oxidation resistance. The reverse osmosis membrane can effectively reduce energy consumption, has a long service life, is simple to operate, can realize industrial production, and has a relatively wide application prospect. DETAILED DESCRIPTION

[0065] The technical solutions of the present application will be further described by specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations on the present application.

[0066] The sources of some components in the preparation examples, examples, comparative examples and performance tests are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] Preparation Example 1

[0071] A support membrane including a non-woven fabric support layer and a polysulfone layer is prepared by dissolving a polysulfone resin in dimethylformamide to obtain a polysulfone casting solution, the mass percentage of the polysulfone resin in the polysulfone casting solution being 16.5 wt%, then uniformly coating and scraping the filtered and defoamed polysulfone casting solution on a polyester non-woven fabric, then placing it in water to perform phase inversion to form a film, and obtaining the support membrane after cleaning, the pore size on the support membrane being in the range of 30-50 nm.

[0072] Example 1

[0073] The present embodiment provides a reverse osmosis membrane and a preparation method thereof, the reverse osmosis membrane including a support membrane layer, a polyamide layer, and a benzene system A and benzene system B modified layer disposed on the polyamide layer.

[0074] The preparation method of the reverse osmosis membrane is as follows:

[0075] (1) immerse the polysulfone layer of the support membrane provided in Preparation Example 1 in an aqueous solution of a polyamine for 30 s, remove it, and use a squeezing roller to remove the excess aqueous solution of the polyamine on the surface, coat an organic solution containing a polyacyl chloride, perform interfacial polymerization at 25°C for 30 s, discard the excess organic solution containing the polyacyl chloride, uniformly blow it away with a air knife until no organic solvent remains on the surface of the membrane, rinse it with 60°C deionized water, and place it in a 60°C oven for drying, to form a polyamide layer on the support membrane;

[0076] The aqueous solution of the polyamine is prepared by mixing m-phenylenediamine with water, stirring at room temperature until complete dissolution, to obtain the aqueous solution of the polyamine, wherein the concentration of the m-phenylenediamine is 2.5 wt%.

[0077] The organic solution of the polyacyl chloride is prepared by mixing trimesoyl chloride with an organic solvent (n-decane), stirring at room temperature until complete dissolution, to obtain the organic solution of the polyacyl chloride, wherein the concentration of the trimesoyl chloride is 0.12 wt%.

[0078] (2) Pouring solution A on the surface of the polyamide layer prepared in step (1), and reacting for 60 s, then pouring off the excess solution A, and placing in an oven for first heat treatment at 85℃ for 1 min, then taking out, rinsing with 80℃ deionized water, and placing in an oven for second heat treatment at 85℃ for 3 min, to form a benzene A modified layer on the polyamide layer, pouring solution B on the surface of the benzene A modified layer, and reacting for 60 s, then pouring off the excess solution B, and placing in an oven for third heat treatment at 85℃ for 1 min, then taking out, rinsing with 80℃ deionized water, and placing in an oven for fourth heat treatment at 85℃ for 3 min, to form a benzene A and benzene B modified layer, to obtain the reverse osmosis membrane.

[0079] The solution A is prepared by mixing 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene and water, and stirring at room temperature until completely dissolved, to obtain the solution A, wherein the concentration of 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene in the solution A is 0.01 wt%.

[0080] The solution B is prepared by mixing 3-amino-4-mercaptobenzoic acid, dimethyl sulfoxide and water, and stirring at room temperature until completely dissolved, to obtain the solution B, wherein the concentration of 3-amino-4-mercaptobenzoic acid in the solution B is 1%, and the concentration of dimethyl sulfoxide is 10%.

[0081] Examples 2-16 differ from Example 1 in the raw materials and contents added, in terms of mass percentage, as shown in Table 2.

[0082] Table 2

[0083]

[0084]

[0085] In Table 2, " / " represents that the substance is not added.

[0086] Example 17

[0087] The present embodiment provides a reverse osmosis membrane and a preparation method thereof, the reverse osmosis membrane comprising a support membrane layer, a polyamide layer, and a benzene A and benzene B modified layer disposed on the polyamide layer.

[0088] The preparation method of the reverse osmosis membrane is as follows:

[0089] (1) immerse the polysulfone layer of the support membrane provided by Preparation Example 1 in an aqueous polyamine solution for 60 s, remove the polysulfone layer, and use a squeeze roller to remove excess aqueous polyamine solution from the surface of the polysulfone layer, coat the polysulfone layer with an organic solution of a polyacyl chloride, perform interfacial polymerization at 20°C for 60 s, pour off the excess organic solution of the polyacyl chloride, and use a wind knife to uniformly blow until no organic solution of the polyacyl chloride remains on the surface of the membrane, rinse with deionized water at 70°C, and place in a drying oven at 70°C to form a polyamide layer on the support membrane;

[0090] The aqueous polyamine solution is prepared by mixing m-phenylenediamine with water, stirring at room temperature until completely dissolved, and obtaining the aqueous polyamine solution, wherein the concentration of m-phenylenediamine is 2.5 wt%.

[0091] The organic solution of the polyacyl chloride is prepared by mixing trimesoyl chloride with an organic solvent (n-decane), stirring at room temperature until completely dissolved, and obtaining the organic solution of the polyacyl chloride, wherein the concentration of trimesoyl chloride is 0.12 wt%.

[0092] (2) pour solution A onto the surface of the polyamide layer obtained in step (1), contact for 300 s to perform a reaction, then pour off the excess solution A, place in an oven for a first heat treatment at 90°C for 3 min, then remove, rinse with deionized water at 90°C, place in an oven for a second heat treatment at 90°C for 6 min, form a benzene A modified layer on the polyamide layer, pour solution B onto the surface of the benzene A modified layer, contact for 300 s to perform a reaction, then pour off the excess solution B, place in an oven for a third heat treatment at 90°C for 3 min, then remove, rinse with deionized water at 60°C, place in an oven for a fourth heat treatment at 90°C for 6 min, form a benzene A and benzene B modified layer, and obtain the reverse osmosis membrane.

[0093] The solution A is prepared by mixing 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene with water, stirring at room temperature until completely dissolved, and obtaining the solution A, wherein the concentration of 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene in the solution A is 0.5 wt%.

[0094] The solution B is prepared by mixing 3-amino-4-mercaptobenzoic acid, dimethyl sulfoxide, and water, stirring at room temperature until completely dissolved, and obtaining the solution B, wherein the concentration of 3-amino-4-mercaptobenzoic acid in the solution B is 1%, and the concentration of dimethyl sulfoxide is 10%.

[0095] Example 18

[0096] The embodiment provides a reverse osmosis membrane and a preparation method thereof, and the reverse osmosis membrane comprises a support membrane layer, a polyamide layer and benzene system A and benzene system B modified layers arranged on the polyamide layer.

[0097] The preparation method of the reverse osmosis membrane is as follows:

[0098] (1) immerse the polysulfone layer in the support membrane provided by the preparation example 1 in a polyamine aqueous solution for 300 s, remove the polysulfone layer after immersion, remove the excess polyamine aqueous solution on the surface of the polysulfone layer by using a pressing roller, coat a polyacyl chloride organic solution, perform an interfacial polymerization reaction at 30 DEG C for 300 s, pour off the excess polyacyl chloride organic solution, uniformly blow the polyacyl chloride organic solution by using a wind knife until no organic solvent is left on the surface of the membrane, rinse the polyamide layer by using 90 DEG C deionized water, and dry the polyamide layer in a 90 DEG C oven, so that the polyamide layer is formed on the support membrane;

[0099] The polyamine aqueous solution is prepared by the following method: mix m-phenylenediamine with water, and stir the mixture at room temperature until the m-phenylenediamine is completely dissolved, so that the polyamine aqueous solution is prepared, wherein the concentration of the m-phenylenediamine is 2.5 wt.%;

[0100] The polyacyl chloride organic solution is prepared by the following method: mix trimesoyl chloride with an organic solvent (mesitylene), and stir the mixture at room temperature until the trimesoyl chloride is completely dissolved, so that the polyacyl chloride organic solution is prepared, wherein the concentration of the trimesoyl chloride is 0.12 wt.%.

[0101] (2) pour solution A on the surface of the polyamide layer prepared in step (1), contact the polyamide layer with solution A for 1200 s to perform a reaction, then pour off the excess solution A, place the polyamide layer in an oven to perform a first heat treatment at 80 DEG C for 10 min, then remove the polyamide layer, rinse the polyamide layer by using 70 DEG C deionized water, place the polyamide layer in the oven to perform a second heat treatment at 80 DEG C for 10 min, form a benzene system A modified layer on the polyamide layer, pour solution B on the surface of the benzene system A modified layer, contact the benzene system A modified layer with solution B for 1200 s to perform a reaction, then pour off the excess solution B, place the benzene system A modified layer in an oven to perform a third heat treatment at 60 DEG C for 10 min, then remove the benzene system A modified layer, rinse the benzene system A modified layer by using 60 DEG C deionized water, place the benzene system A modified layer in the oven to perform a fourth heat treatment at 60 DEG C for 10 min, form a benzene system A and benzene system B modified layer, and obtain the reverse osmosis membrane.

[0102] The solution A is prepared by the following method: mix 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene with water, and stir the mixture at room temperature until the 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene is completely dissolved, so that the solution A is prepared, wherein the concentration of the 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene in the solution A is 0.5 wt.%.

[0103] The solution B is prepared by mixing 3-amino-4-mercapto benzoic acid, dimethyl sulfoxide and water, and stirring at room temperature until the 3-amino-4-mercapto benzoic acid is completely dissolved, to obtain the solution B, wherein the concentration of 3-amino-4-mercapto benzoic acid is 1% and the concentration of dimethyl sulfoxide is 10%.

[0104] Example 19

[0105] The present example provides a reverse osmosis membrane and a preparation method thereof, which are different from those of example 1 only in that the reverse osmosis membrane comprises a support membrane layer, a polyamide layer and a benzene system A modified layer disposed on the polyamide layer.

[0106] In step (2) of the preparation method, solution A is poured onto the surface of the polyamide layer prepared in step (1), and the reaction is carried out by contacting for 60 s, then the excess solution A is poured out, and the first heat treatment is carried out in an oven at 85°C for 1 min, then the polyamide layer is taken out, rinsed with 80°C deionized water, and the second heat treatment is carried out in an oven at 85°C for 3 min, to form the benzene system A modified layer on the polyamide layer, thereby obtaining the reverse osmosis membrane.

[0107] The other conditions are the same as those of example 1.

[0108] Example 20

[0109] The present example provides a reverse osmosis membrane and a preparation method thereof, which are different from those of example 1 only in that the reverse osmosis membrane comprises a support membrane layer, a polyamide layer and a benzene system A and benzene system B modified layer disposed on the polyamide layer.

[0110] In step (2), no dimethyl sulfoxide is added to the solution B, the concentration of 3-amino-4-mercapto benzoic acid is 1%, and the concentration of water is 99%, and the other conditions are the same as those of example 1.

[0111] Comparative example 1

[0112] The present example provides a reverse osmosis membrane and a preparation method thereof, which are different from those of example 1 only in that the reverse osmosis membrane comprises a support membrane layer, a polyamide layer and a benzene system A and benzene system B modified layer disposed on the polyamide layer.

[0113] In step (2) of the preparation method, solution B is poured onto the surface of the polyamide layer prepared in step (1), and the reaction is carried out by contacting for 60 s, then the excess solution B is poured out, and the first heat treatment is carried out in an oven at 85°C for 1 min, then the polyamide layer is taken out, rinsed with 80°C deionized water, and the second heat treatment is carried out in an oven at 85°C for 3 min, to form the benzene system B modified layer, thereby obtaining the reverse osmosis membrane.

[0114] The other conditions are the same as those of example 1.

[0115] Comparative Example 2

[0116] The present comparative example provides a reverse osmosis membrane and a preparation method thereof, which is only different from Example 1 in that the reverse osmosis membrane comprises a support membrane layer and a polyamide layer, and does not comprise the benzene series A and benzene series B modification layers.

[0117] The preparation method does not comprise step (2), and other conditions are the same as those of Example 1.

[0118] Performance test

[0119] The reverse osmosis membranes provided by the above examples and comparative examples are tested, and the specific test method is as follows:

[0120] (1) Test of desalination rate and permeation flux

[0121] The permeation flux and the desalination rate are two important parameters for evaluating the separation performance of the reverse osmosis membrane, and the separation performance is evaluated according to GB / T32373-2015 “Test method for reverse osmosis membrane”.

[0122] The desalination rate (R) is defined as the difference between the salt concentration (C f ) of the feed liquid and the salt concentration (C p ) in the permeate under certain operating conditions, divided by the salt concentration (C f ) of the feed liquid, as shown in formula (1).

[0123]

[0124] The permeation flux is defined as the volume of water per unit membrane area per unit time under certain operating conditions, and the unit is L / (m 2 ·h).

[0125] The reverse osmosis membranes provided by the above examples and comparative examples are tested for permeation flux and desalination rate, and the operating conditions used are as follows: the feed liquid is a 2000 ppm sodium chloride aqueous solution, the solution pH is 7.0, the operating pressure is 1.55 MPa, and the operating temperature is 25℃, to obtain the initial permeation flux and the initial desalination rate.

[0126] (2) Test of oxidation resistance

[0127] According to the changes of the permeation flux and the desalination rate before and after the sodium hypochlorite treatment, the oxidation resistance of the reverse osmosis membrane is characterized.

[0128] The sodium hypochlorite treatment step comprises: preparing a sodium hypochlorite solution with a concentration of 1000 ppm, adjusting the pH of the solution to 7.0 with 1 mol / L hydrochloric acid, immersing the reverse osmosis membrane into the sodium hypochlorite solution for 24 h, then taking out and repeatedly rinsing the membrane surface with deionized water, then immersing the reverse osmosis membrane into a 0.1 wt% sodium bisulfite solution to remove residual active chlorine, rinsing the membrane surface with deionized water, and then immersing the reverse osmosis membrane in deionized water for 2 h to obtain a sodium hypochlorite-treated reverse osmosis membrane.

[0129] The desalination rate and permeation flux of the sodium hypochlorite-treated reverse osmosis membrane are tested under the following operating conditions: the feed liquid is a 2000 ppm sodium chloride aqueous solution, the solution pH is 7.0, the operating pressure is 1.55 MPa, and the operating temperature is 25°C, to obtain the desalination rate after sodium hypochlorite treatment and the permeation flux after sodium hypochlorite treatment.

[0130] The desalination rate change rate before and after sodium hypochlorite treatment is calculated as follows:

[0131] Desalination rate change rate before and after sodium hypochlorite treatment = desalination rate after sodium hypochlorite treatment - initial desalination rate.

[0132] (3) Oxidation resistance test after acid-base cleaning

[0133] The desalination rate after acid-base cleaning is tested after the reverse osmosis membranes provided in the examples and comparative examples are respectively operated under alkaline (pH = 12, NaOH) conditions for 12 h and under acidic (pH = 2, HCl) conditions for 2 h.

[0134] The desalination rate after sodium hypochlorite cleaning after acid-base cleaning is tested after the reverse osmosis membranes provided in the examples and comparative examples are respectively operated under alkaline (pH = 12, NaOH) conditions for 12 h and under acidic (pH = 2, HCl) conditions for 2 h, and then subjected to the above oxidation resistance test.

[0135] The desalination rate test is performed under the following operating conditions: the feed liquid is a 2000 ppm sodium chloride aqueous solution, the solution pH is 7.0, the operating pressure is 1.55 MPa, and the operating temperature is 25°C.

[0136] The chlorine resistance after acid-base cleaning is calculated as follows:

[0137] Chlorine resistance after acid-base cleaning = desalination rate after sodium hypochlorite cleaning after acid-base cleaning - desalination rate after acid-base cleaning.

[0138] (4) Antibacterial performance test

[0139] The antibacterial performance experiment is performed according to GB / T 37206-2018 using Escherichia coli as the bacterial strain.

[0140] The number A corresponds to the reverse osmosis membrane prepared in Comparative Example 2, used as a blank reference, the numbers B1-B20 correspond to the reverse osmosis membranes prepared in Examples 1-20, and the number B21 corresponds to the reverse osmosis membrane prepared in Comparative Example 1.

[0141] The reverse osmosis membranes to be tested were cut into circles with a diameter of (20±1) mm and sterilized after multiple washing; 23 sterile petri dishes were taken, 22 of which were added with the reverse osmosis membranes numbered A and B1-B21 respectively, and one sterile petri dish was blank cultured without adding the reverse osmosis membrane, 0.4 mL of the test bacterial suspension was taken and dropped on the petri dish; the reverse osmosis membranes corresponding to the numbers were uniformly contacted with the bacterial suspension, and were placed in a constant temperature and humidity incubator with a temperature of 37°C and a humidity of 90% for 2 h; then they were taken out and washed with phosphate buffer to obtain the washing liquid, 1 mL of the washing liquid was diluted by 10 times step by step to obtain the dilution liquid; 1 mL of the dilution liquid was uniformly coated on the plate count agar, and was cultured again in a constant temperature and humidity environment at 37°C for 24 h, and then was taken out and colony counting was performed;

[0142] The bacteriostasis rate (K) was calculated according to the following formula:

[0143] K(%) = [(A-B) / A] x 100%;

[0144] In the formula, K is the bacteriostasis rate, %; A is the number of colonies after blank culture without adding the reverse osmosis membrane, CFU; and B is the number of colonies after culture with the reverse osmosis membrane, CFU.

[0145] (5) Membrane surface element analysis

[0146] X-ray photoelectron spectroscopy (XPS) is a very sensitive surface analysis method, and the detection signal comes from the material surface of 2-5 nm, which can characterize the types and percentage contents of each element on the surface.

[0147] The types and percentage contents of the elements on the surface of the reverse osmosis membranes provided in Example 4, Example 19 and Comparative Examples 1-2 were characterized by XPS. Before testing, the reverse osmosis membranes were dried in a vacuum oven at 40°C for 24 h, three points of each sample were tested, and the average value was taken.

[0148] The test results are shown in Tables 3 and 4 as follows:

[0149] Table 3

[0150]

[0151]

[0152] Table 4

[0153]

[0154] "-" in Table 4 represents that the result is not measured.

[0155] From the test results in Table 3, it can be seen that the reverse osmosis membranes provided in Examples 1-20 have excellent oxidation resistance and antibacterial properties while ensuring high permeation flux and high desalination rate, and can still maintain good performance under acid and alkali cleaning conditions.

[0156] From the test results in Table 4, it can be seen that by element analysis of the membrane surface of the reverse osmosis membranes provided in Example 4 and the reverse osmosis membranes provided in Comparative Examples 1 and 2, the surface element composition and proportion change, and sulfur element is detected in Example 4 and Example 19, proving that the disulfide bond is successfully grafted to the surface of the reverse osmosis membrane.

[0157] Compared with Example 4, if the concentration of benzene A in solution A is too low (Example 1), the oxidation resistance, acid and alkali resistance, and antibacterial properties are all reduced; if the concentration of benzene A in solution A is too high (Example 5), the initial permeation flux is reduced, and the oxidation resistance, acid and alkali resistance, and antibacterial properties are also slightly reduced, thus it can be known that the performance is better when the concentration of benzene A in solution A is in the range of 0.1wt% to 0.5wt%.

[0158] Compared with Example 4, if 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene is replaced by 2,2'-(2-pyridyl)-6,6'-amino-7,7'-phenoxy-disulfide benzene of the same mass (Example 6), the initial permeation flux, oxidation resistance, acid and alkali resistance, and antibacterial properties are all reduced, thus it can be known that the performance of benzene A is better when benzene A is 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene.

[0159] Compared with Example 4, if the concentration of benzene B in solution B is too low (Example 7), the initial permeation flux is reduced, and the oxidation resistance, acid and alkali resistance, and antibacterial properties are also reduced; if the concentration of benzene B in solution B is too high (Example 9), the oxidation resistance is greatly reduced, thus it can be known that the performance is better when the concentration of benzene B in solution B is in the range of 0.2wt% to 1wt%.

[0160] Compared with Example 4, if 3-amino-4-mercaptobenzoic acid is replaced by 5-fluoro-2-mercaptobenzoic acid of the same mass (Example 10), the initial permeation flux, oxidation resistance, acid and alkali resistance, and antibacterial properties are all reduced, thus it can be known that the performance of benzene B is better when benzene B is 3-amino-4-mercaptobenzoic acid.

[0161] Compared with Example 4, if the concentration of dimethyl sulfoxide in solution B is too low (Example 13), the reaction intensity is low, the carboxyl groups in benzene series B cannot be well connected to the reverse osmosis membrane surface, and the initial flux decreases; if the concentration of dimethyl sulfoxide in solution B is too high (Example 14), the side reaction increases, and the carboxyl groups in benzene series B also cannot be well connected to the reverse osmosis membrane surface, and the initial flux decreases, thus it can be known that the concentration of dimethyl sulfoxide in solution B is better within the range of 8wt%-12wt%.

[0162] Compared with Example 4, if benzene series B is not added for modification (Example 19), the initial permeation flux, oxidation resistance, acid and alkali resistance, and antibacterial property all decrease.

[0163] Compared with Example 4, if dimethyl sulfoxide is not added in solution B (Example 20), the initial flux, oxidation resistance, and acid and alkali resistance all decrease.

[0164] Compared with Example 4, if benzene series B is not added for modification (Comparative Example 1), the oxidation resistance, acid and alkali resistance, and antibacterial property greatly decrease.

[0165] Compared with Example 4, if the reverse osmosis membrane does not include the modification layers of benzene series A and benzene series B (Comparative Example 2), the oxidation resistance, acid and alkali resistance, and antibacterial property greatly decrease.

[0166] The applicant declares that the reverse osmosis membrane, the preparation method and the application thereof of the present application are illustrated by the above examples, but the present application is not limited to the above examples, that is, it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for producing a reverse osmosis membrane, characterized by, The preparation method comprises the following steps: (1) a polyamine and a polyacyl chloride are subjected to a polymerization reaction on a support film to form a polyamide layer on the support film; (2) the polyamide layer prepared in step (1) is reacted with a benzene A to obtain the reverse osmosis membrane; The benzene A is a benzene containing an amino group, an antibacterial group, a disulfide bond and a phenoxy group; the antibacterial group comprises an indole group and / or a pyridine group.

2. The production method according to claim 1, characterized by, The benzene A comprises 1-(1H-indole-3,3'-disulfide)-4,4'-amino-5-methoxybenzene and / or 2,2'-(2-pyridyl)-6,6'-amino-7,7'-phenoxy-disulfide benzene.

3. The production method according to claim 1, characterized by, After the reaction in step (2), the benzene B containing a mercapto group and a carboxyl group is further reacted.

4. The production method according to claim 3, characterized by, The reaction with the benzene B is carried out in the presence of dimethyl sulfoxide.

5. The preparation method according to claim 3, characterized in that The benzene B comprises any one or a combination of at least two of 3-amino-4-mercaptobenzoic acid, 5-fluoro-2-mercaptobenzoic acid and 3-mercaptobenzoic acid.

6. The production method according to claim 1 or 2, characterized by, The support film comprises a non-woven fabric support layer and a polysulfone layer.

7. The production method according to claim 1 or 2, characterized by, The polyamine comprises m-phenylenediamine.

8. The production method according to claim 1 or 2, characterized by, The polyacyl chloride comprises trimesoyl chloride.

9. The method of claim 1, wherein, Step (1) specifically comprises the following steps: after the support film is subjected to a first contact with an aqueous solution of a polyamine, the support film is subjected to a second contact with an organic solution of a polyacyl chloride, so that the polyacyl chloride and the polyamine are subjected to a polymerization reaction to obtain a polyamide layer.

10. The method of claim 9, wherein, The concentration of the polyamine in the aqueous solution of the polyamine is 1.0wt%-3.0wt%.

11. The preparation method according to claim 9, characterized in that The concentration of the polyacyl chloride in the organic solution of the polyacyl chloride is 0.08wt%-0.2wt%.

12. The method of claim 9, wherein, The temperature of the first contact in step (1) is 20-30°C, and the time is 10-300s.

13. The preparation method according to claim 9, characterized in that The temperature of the first contact in step (1) is 20-30°C, and the time is 30-60s.

14. The method of claim 9, wherein, The temperature of the second contact in step (1) is 20-30°C, and the time is 10-300s.

15. The preparation method according to claim 9, characterized in that The temperature of the second contact in step (1) is 20-30°C, and the time is 30-60s.

16. The method of claim 9, wherein, After the polymerization reaction in step (1), the following steps are further included: removing the excess organic solution of the polyacyl chloride, water washing and drying.

17. The preparation method according to claim 16, characterized in that The temperature of the water washing in step (1) is 60-90°C.

18. The method of claim 16, wherein, The temperature of the drying in step (1) is 60-90°C.

19. The method of claim 3, wherein, Step (2) specifically comprises the following steps: the polyamide layer prepared in step (1) is subjected to a first contact with solution A, a first heat treatment, a second heat treatment, a benzene A modified layer is formed on the polyamide layer, and then subjected to a second contact with solution B, a third heat treatment, a fourth heat treatment, a benzene A and benzene B modified layer is formed, and the reverse osmosis membrane is obtained; Solution A comprises benzene A and water; Solution B comprises benzene B, dimethyl sulfoxide and water.

20. The method of claim 19, wherein, The concentration of benzene A in solution A is 0.01wt%-1wt%.

21. The method of claim 19, wherein, The concentration of benzene A in solution A is 0.1wt%-0.5wt%.

22. The preparation method according to claim 19, characterized in that The concentration of benzene B in solution B is 0.02wt%-2wt%.

23. The preparation method according to claim 19, characterized in that The concentration of benzene B in solution B is 0.2wt%-1.0wt%.

24. The method of claim 19, wherein, The concentration of dimethyl sulfoxide in the solution B is 5wt% to 25wt%.

25. The preparation method according to claim 19, characterized in that The concentration of dimethyl sulfoxide in the solution B is 8wt% to 12wt%.

26. The method of claim 19, wherein, The first contact in step (2) is for 10 to 1200 seconds.

27. The preparation method according to claim 19, characterized in that The first contact in step (2) is for 30 to 300 seconds.

28. The preparation method according to claim 19, characterized in that Step (2) further comprises a step of removing the excess solution A before the first heat treatment.

29. The preparation method according to claim 19, characterized in that Step (2) further comprises a step of water washing after the first heat treatment.

30. The method of claim 19, wherein, The first heat treatment in step (2) is at a temperature of 60 to 100℃ for 0.5 to 10 minutes.

31. The preparation method according to claim 19, characterized in that The first heat treatment in step (2) is at a temperature of 80 to 90℃ for 1 to 3 minutes.

32. The preparation method according to claim 19, characterized in that The second heat treatment in step (2) is at a temperature of 60 to 100℃ for 0.5 to 10 minutes.

33. The method of claim 19, wherein the method further comprises: The second heat treatment in step (2) is at a temperature of 80 to 90℃ for 3 to 6 minutes.

34. The method of claim 19, wherein the method further comprises, The second contact in step (2) is for 10 to 1200 seconds.

35. The method of claim 19, wherein the method further comprises: The second contact in step (2) is for 30 to 300 seconds.

36. The method of claim 19, wherein the method further comprises: Step (2) further comprises a step of removing the excess solution B before the third heat treatment.

37. The method of claim 19, wherein the method is carried out at a temperature of about 20°C to about 30°C. Step (2) further comprises a step of water washing after the third heat treatment.

38. The method of claim 19, wherein the method is carried out at a temperature of about 20°C to about 30°C. The third heat treatment in step (2) is at a temperature of 60 to 100℃ for 0.5 to 10 minutes.

39. The method of claim 19, wherein, The third heat treatment in step (2) is at a temperature of 80 to 90℃ for 1 to 3 minutes.

40. The method of claim 19, wherein, The fourth heat treatment in step (2) is at a temperature of 60 to 100℃ for 0.5 to 10 minutes.

41. The method of claim 19, wherein the method is carried out at a temperature of about 20°C to about 30°C. The fourth heat treatment in step (2) is at a temperature of 80 to 90℃ for 3 to 6 minutes.

42. A reverse osmosis membrane, characterized in that, The reverse osmosis membrane is prepared by the method of any one of claims 1 to 41.

43. Use of the reverse osmosis membrane of claim 42 in a water treatment assembly or a water treatment method.

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