WO2019179082A1

WO2019179082A1 - Metal organic frame reverse osmosis membrane and preparation method therefor

Info

Publication number: WO2019179082A1
Application number: PCT/CN2018/110429
Authority: WO
Inventors: 章冰洁; 康燕; 梁松苗
Original assignee: 时代沃顿科技有限公司
Priority date: 2018-03-20
Filing date: 2018-10-16
Publication date: 2019-09-26
Also published as: CN108452684A; CN108452684B

Abstract

A metal organic frame reverse osmosis membrane and a preparation method therefor. A support layer of said reverse osmosis membrane is synthesized from a polymer and an active hydrophilic stabilizer. A desalting layer on the support layer is a functional layer which has a cross-linked nanocrystal network structure and is formed by subjecting the support layer to an interfacial polymerization reaction of an aqueous phase solution and an oil phase solution. The preparation method for said reverse osmosis membrane comprises preparation of a polymer support layer, preparation of a metal organic framework nano ion, and preparation of a desalting layer. The presence of the metal organic framework provides a large number of hydrogen bonds to the functional layer, and at the same time, the metal organic framework can crosslink and condensate with free amino groups in the functional layer, thereby increasing the degree of crosslinking of the reverse osmosis membrane. The reverse osmosis membrane has a small film thickness, greatly saving manufacturing costs. More importantly, the reverse osmosis membrane can greatly increase the membrane flux without affecting the salt removing rate so that the operating energy consumption of the membrane is reduced, and thus is a low-energy consumption seawater desalting membrane having superior properties.

Description

Metal organic frame reverse osmosis membrane and preparation method thereof

Technical field

The present disclosure relates to the field of reverse osmosis membrane modification technology, in particular to a metal organic framework reverse osmosis membrane and a preparation method thereof.

Background technique

Water is the source of life, and it is an indispensable condition for humans, animals and plants to survive. The seawater and brackish water on the earth account for more than 97.4% of the world's total water. How to desalinate seawater is the most direct and effective means to solve the water shortage. At present, the world's desalination technology is mainly divided into thermal and membrane methods. The thermal method mainly includes multi-stage flash (MSF), multi-effect distillation (MED) and gas-phase compression distillation (VCD); membrane method mainly has reverse osmosis ( RO) and nanofiltration (NF). Among them, membrane desalination technology, especially seawater reverse osmosis membrane desalination technology has the advantages of low cost, stable performance and high quality water under low energy consumption conditions. It is called “green” pure water preparation system and has occupied the global desalination market. About 60%, but the high energy consumption caused by its high operating pressure has always made the seawater desalination cost high, which is also a bottleneck that plagues the popularization of membrane technology.

The seawater reverse osmosis membrane method has reduced the cost of seawater desalination to one-fifth, but energy conservation is an eternal topic that has been followed up all over the world. How to reduce the cost of membrane method has been the direction of many scientific and technological personnel, due to energy consumption in membrane method. The cost of consumption is 50-60% of the total cost. Therefore, how to reduce the energy consumption of the seawater membrane method becomes the most important breakthrough in cost saving (Zarzo et al., Desalination, 2018, 427, 1-9). For example, the development of larger-diameter membrane elements to achieve large-scale projects of millions of tons; pretreatment of reverse osmosis water by means of nanofiltration-reverse osmosis or electrodialysis-reverse osmosis; preparation of energy recovery devices Etc. will be an effective way to reduce seawater costs.

As the core of the seawater desalination membrane method, the reverse osmosis membrane will greatly reduce the energy consumption. It has been reported that if the flux of the reverse osmosis membrane is increased to more than three times that of the existing polyamide membrane, the pressure vessel can be reduced by 44% to reduce the depletion energy consumption of the 15% seawater reverse osmosis membrane (David et al., Energy). Environ. Sci., 2014, 7, 1134-1141). Therefore, how to improve the flux of the membrane under the condition of ensuring the quality of the effluent and combine the high water yield with the low energy consumption has always been the goal pursued by the global polyamide composite reverse osmosis membrane workers. Many companies have also developed many low pressure and low energy. Consumption of reverse osmosis membrane products. However, the flux and desalination rate of the membrane usually vary, which is difficult to achieve. Therefore, how to greatly increase the membrane flux under the premise of ensuring the quality of the effluent has been a research hotspot (Park et al., Science, 2017, 356, 1137). Therefore, advanced membrane materials have also been developed and improved, such as the preparation of modified reverse osmosis membranes containing aquaporins, nanoporous graphene, covalent triazine frameworks, molybdenum dioxide, organic porous cages, zeolite nanosheets and other materials. Materials (CN105457494, CN102438736, Alireza et al., J Membr. Sci., 2017, 531, 59-67), on the one hand, to prepare a thinner polyamide reverse osmosis membrane functional layer, making its pore structure more regular, and On the one hand, certain materials modified reverse osmosis membranes can provide a size-controlled inlet channel. Therefore, how to improve the material of the reverse osmosis membrane, and then optimize the performance by adjusting the structure of the functional layer, so that maintaining the high salt rejection rate while greatly increasing the flux of the reverse osmosis membrane is an urgent need to prepare a low pressure and low energy reverse osmosis membrane. One of the important issues.

Summary of the invention

In order to solve the problem of high energy consumption of the seawater membrane method, the present disclosure aims to provide a high-throughput low-energy seawater desalination reverse osmosis membrane and a preparation method thereof. The blending of crosslinked metal organic framework materials in the functional layer of reverse osmosis membrane can obtain advanced mixed matrix membranes (MMMs). The introduction of this material improves the thermal stability and mechanical properties of the membrane on the one hand, and the metal organic of the size can be regulated on the other hand. The framework nanochannel provides a selective water inlet channel, and the metal organic framework nano material can form a large number of hydrogen bonds on the one hand to increase the hydrophilicity of the surface of the membrane, and on the other hand, the inherent carboxylate can be condensed and polymerized with the acid chloride to form a total The valence bond increases the degree of crosslinking of the functional layer of the membrane, so the introduction of the material can greatly increase the flux of the membrane without losing the salt rejection rate of the membrane. In addition, the present application produces a thinner seawater membrane by controlling the process conditions, which on the one hand saves costs and on the other hand increases the water flux of the membrane. It has the feature of solving the technical problem that the reverse osmosis membrane of the prior art has high system energy consumption due to low flux.

This is achieved through the following technical solutions:

A metal organic framework reverse osmosis membrane characterized in that the support layer is synthesized by a polymer and an active hydrophilic stabilizer, the aqueous phase solution comprises a catalyst and an aqueous phase monomer, and the oil phase solution comprises a metal organic framework nano material and an oil phase single The desalting layer on the support layer is a functional layer of the support layer formed by the interfacial polymerization of the aqueous phase solution and the oil phase solution to form a crosslinked nanocrystal network structure.

The polymer is one of polysulfone or polyethersulfone, and has a concentration of 16 wt% to 20 wt% in the solution for preparing the support layer.

The active hydrophilic stabilizer is polyvinylpyrrolidone, and the concentration in the solution for preparing the support layer is 0.15 wt% to 5 wt%.

The solution for preparing the support layer is N,N-dimethylformamide (DMF), and the part other than the polymer and the active hydrophilic stabilizer is N,N-dimethylformamide (DMF). Added to 100% by weight.

The catalyst is a mixture of a phase transfer catalyst and an acid binding agent; wherein the phase transfer catalyst is tetrabutylammonium chloride, triethylamine hydrochloride, benzyltriethylammonium chloride, dodecyltrimethyl The concentration of one of the ammonium chlorides in the aqueous phase solution is from 0.5% by weight to 5.0% by weight; the acid binding agent is triethylamine, and the concentration in the aqueous phase solution is from 0.5% by weight to 5.0% by weight.

The aqueous phase monomer is m-phenylenediamine, and the concentration in the aqueous phase solution is from 0.5 wt% to 5.0 wt%.

The metal organic framework nano material is composed of silver ions and trimesic acid, the mass ratio of which is 1:1, the active functional group is a carboxyl group, and the concentration in the oil phase solution is 0.02 wt% to 0.1 wt%.

The oil phase monomer is one of phthaloyl chloride, terephthaloyl chloride, isophthaloyl chloride, 4,4'-biphenyldichloride, and trimesoyl chloride in an oil phase solution. The concentration in the range is 0.005 wt% to 3 wt%.

The oil phase solution has a solvent of one or more of n-hexane, cyclohexane, n-heptane and Isopar G.

A method for preparing a metal organic framework reverse osmosis membrane comprises the following steps:

(1) Preparation of metal organic framework nanomaterials: silver nitrate and N,N-dimethylformamide (DMF) were ultrasonically dispersed for 10 min at a mass ratio of 1:38, and trimesic acid and N,N-dimethyl The base formamide (DMF) was ultrasonically dispersed for 10 min at a mass ratio of 1:38, and the mixture was ultrasonicated for 1 h, centrifuged and filtered, and the obtained solid was washed with a mixture of water and ethanol (V water: V ethanol = 1:1). ~5 times, drying at 60 ° C for 24h, the resulting metal organic framework nanomaterials are retained in the vacuum dryer until use;

(2) Preparation of support layer: 0.15 wt% to 5 wt% of polyvinylpyrrolidone and N,N-dimethylformamide (DMF) are mixed and dispersed, and stirred at a stirring speed of 60-90 r/min. The polyvinylpyrrolidone is uniformly dispersed in a solution of N,N-dimethylformamide (DMF), the stirring speed is maintained to 90 ° C, and a polymer having a mass concentration of 16 wt% to 20 wt% is added thereto, and the balance is N. N-dimethylformamide (DMF) was added to 100% to obtain a solution for preparing a support layer, followed by vacuum defoaming treatment at -80 kPa, followed by filtration, cooling to room temperature, and coating the solution on a nonwoven fabric base. The material enters the coagulation bath and is then placed in deionized water for 200 s to obtain a support layer;

(3) Preparation of desalting layer: the support layer prepared in the step (2) is immersed in deionized water for 30 min, and the support layer is taken out from the deionized water, and contains 0.5 wt% to 5 wt% of m-phenylenediamine, 0.5 wt. The aqueous solution of %~5wt% triethylamine and 0.5wt%~5wt% phase transfer catalyst is contacted for 40s~60s, so that the aqueous phase solution penetrates into the pore of the support layer; the excess aqueous solution is filtered, and the aqueous phase liquid on the surface of the membrane is filtered. The droplet is removed by a rolling rubber roller; the membrane is immersed in the oil phase solution for 30 s to 60 s, and the oil phase solution contains 0.02 wt% to 0.1 wt% of the metal organic framework nanomaterial and 0.005 wt% to 3 wt% of phthaloyl chloride, One of phthaloyl chloride, isophthalic acid chloride, phthaloyl dichloride, and trimesoyl chloride. The membrane was taken out and washed with dilute hydrochloric acid for 5 min, infiltrated with glycerin aqueous solution for 5 min, and placed in an oven at 30 ° C to 90 ° C. Drying in the middle, that is.

In the step (3), the preparation ratio of the support layer to the aqueous phase solution and the oil phase solution is 100 g: 4-6 L: 4-6 L.

The ultrasound has a power of 24 kHz and an output and pulse of 80 w and 0.6, respectively.

The oven temperature is from 30 ° C to 90 ° C, preferably 80 ° C.

The coagulation bath is an aqueous solution of N,N-dimethylformamide (DMF) having a mass fraction of 1.0%.

The dilute hydrochloric acid and the hydrogen chloride have a mass concentration of 2%.

The aqueous glycerin solution has a glycerin concentration of 8%.

Compared with the prior art, the present disclosure has the following advantages:

The present disclosure adds a phase transfer catalyst to the aqueous phase to increase the rate of polymerization, to make the prepared polyamide reverse osmosis membrane have more regular and dense pores, and more importantly, to add metal organic framework nanomaterials to the oil phase. The prepared reverse osmosis membrane is thinner and provides an additional water inlet channel, and the size-regulated nanochannel does not affect the membrane salt rejection rate. In general, the preparation method of the metal organic framework nano material modified polyamide seawater membrane functional layer greatly improves the membrane flux without affecting the seawater membrane salt rejection rate, and the operation is simple and the production cost is low. In addition, by adjusting the process parameters in the preparation process and combining the metal organic framework with the polymer functional layer, the presence of the metal organic framework not only provides a large number of hydrogen bonds to the functional layer, but also a free amino group in the functional layer. The cross-linking condensation polymerization is carried out to form a covalent bond, and the produced reverse osmosis membrane has a thickness of about 100 nm.

detailed description

The technical solutions created by the present disclosure are further explained and explained in conjunction with the specific embodiments and experimental examples in order to facilitate a person skilled in the art to fully understand the present disclosure, but the explanation and description are not the technical solutions of the present disclosure. Further definitions, the simple numerical substitutions made on the basis of the invention, and the improved technical solutions of the conventional adjustments are all within the scope of protection created by the present disclosure.

Additional instructions:

The mass percentage of polysulfone, polyethersulfone, and polyvinylpyrrolidone in the present specification is the mass percentage in the solution for preparing the support layer.

The mass percentage of tetrabutylammonium chloride, triethylamine hydrochloride, benzyltriethylammonium chloride, dodecyltrimethylammonium chloride, triethylamine and m-phenylenediamine in the present specification Is the mass percentage in the aqueous phase solution.

In the present specification, the metal organic framework nano material, phthaloyl chloride, terephthaloyl chloride, isophthaloyl chloride, 4,4'-biphenyldichloride, trimesoyl chloride, n-hexane, cyclohexane, The mass percentage of n-heptane and Isopar G are the mass percentages in the oil phase solution.

Example 1

(1) Preparation of metal organic framework nanomaterials: silver nitrate and N,N-dimethylformamide (DMF) were ultrasonically dispersed for 10 min at a mass ratio of 1:38, and trimesic acid and N,N-dimethyl The base formamide (DMF) was ultrasonically dispersed for 10 min at a mass ratio of 1:38, and the mixture was ultrasonicated for 1 h, centrifuged and filtered, and the resulting precipitate was washed with a mixture of water and ethanol (V water: V ethanol = 1:1). After drying at 60 ° C for 24 h, the resulting metal organic framework nanomaterial was retained for use in a vacuum desiccator.

(2) Preparation of support layer: 0.15wt% polyvinylpyrrolidone and N,N-dimethylformamide (DMF) were mixed and dispersed, and stirred at a stirring speed of 60r/min, so that polyvinylpyrrolidone was Disperse uniformly in N,N-dimethylformamide (DMF) solution, maintain the stirring speed to 90 ° C, add 16 wt% polysulfone, and the remainder is supplemented with N,N-dimethylformamide (DMF). 100wt%, the solution for preparing the support layer is obtained, and then vacuum defoaming treatment is carried out at -80 kPa, filtered, cooled to room temperature, uniformly coated on the non-woven substrate by a doctor blade system and entered into a coagulation bath, and the coagulation bath is of mass. A 1.0% aqueous solution of DMF was applied at a temperature of 20 ° C; then it was placed in deionized water at a temperature of 20 ° C. After 200 s of treatment, a support layer was obtained.

(3) Preparation of desalting layer: The support layer prepared in the step (2) was immersed in deionized water for 30 min, and the support layer was taken out from the deionized water, and contained with 0.5 wt% of m-phenylenediamine and 0.5 wt% of triethyl An aqueous solution of amine, 0.5 wt% tetrabutylammonium chloride is contacted for 40 s to allow the aqueous phase solution to penetrate into the pores of the support layer; the excess aqueous solution is filtered off, and the aqueous phase droplets on the surface of the membrane are removed by a rolling rubber roller; The membrane was immersed in an oil phase solution containing Isopar G as a solvent and containing 0.02 wt% of metal organic framework nanomaterial and 0.005 wt% of phthaloyl chloride for 30 s, and then the membrane was taken out and washed with 2.0 wt% of dilute hydrochloric acid, and washed. After 5 min, it was placed in 8.0 wt% aqueous glycerin solution, the temperature of glycerin was 60 ° C, and the infiltration time was 5 min. Finally, the prepared metal organic frame reverse osmosis membrane was dried in an oven at 60 ° C to obtain SWRO-MOFs-1 Penetration membrane.

In the step (3), the preparation ratio of the support layer to the aqueous phase solution and the oil phase solution is 100 g: 4 L: 4 L.

Example 2

(2) Preparation of support layer: 1 wt% polyvinylpyrrolidone and N,N-dimethylformamide (DMF) were mixed and dispersed, and stirred at a stirring speed of 70 r/min to make polyvinylpyrrolidone in N , N-dimethylformamide (DMF) solution was uniformly dispersed, maintaining the stirring speed to 90 ° C, adding 17 wt% polysulfone, and the remainder was supplemented with N,N-dimethylformamide (DMF) to 100 wt. %, the solution for preparing the support layer is obtained, and then vacuum defoaming treatment is carried out at -80 kPa, filtered, cooled to room temperature, uniformly coated on the non-woven substrate by a doctor blade system, and entered into a coagulation bath, and the coagulation bath is a mass fraction. It was a 1.0% aqueous solution of DMF at a temperature of 20 ° C; it was then placed in deionized water at a temperature of 20 ° C. After 200 s of treatment, a support layer was obtained.

(3) Preparation of desalting layer: the support layer prepared in the step (2) was immersed in deionized water for 30 min, and the support layer was taken out from the deionized water, and contained with 1 wt% of m-phenylenediamine, 1 wt% of triethylamine, The aqueous phase solution of 1 wt% triethylamine hydrochloride is contacted for 45 s to allow the aqueous phase solution to penetrate into the pores of the support layer; the excess aqueous solution is filtered off, and the aqueous phase droplets on the surface of the membrane are removed by a rolling rubber roller; After immersing in an oil phase solution containing Isopar G as a solvent and containing 0.04 wt% of metal organic framework nanomaterials and 0.5 wt% of terephthalic acid chloride for 40 s, the membrane was taken out and washed with 2.0 wt% of dilute hydrochloric acid for 5 min. Then, it is placed in a 8.0 wt% aqueous solution of glycerin, the temperature of glycerin is 60 ° C, and the infiltration time is 5 min. Finally, the prepared metal organic frame reverse osmosis membrane is dried in an oven at 70 ° C to obtain a SWRO-MOFs-2 reverse osmosis membrane. .

In the step (3), the preparation ratio of the support layer to the aqueous phase solution and the oil phase solution is 100 g: 4 L: 5 L.

Example 3

(2) Preparation of support layer: 2.5wt% polyvinylpyrrolidone and N,N-dimethylformamide (DMF) were mixed and dispersed, and stirred at a stirring speed of 75r/min, so that polyvinylpyrrolidone was Disperse uniformly in N,N-dimethylformamide (DMF) solution, maintain the stirring speed to 90 ° C, add 18 wt% polyethersulfone, and the remainder is supplemented with N,N-dimethylformamide (DMF). To 100 wt%, a solution for preparing a support layer was obtained, and then vacuum defoaming treatment was carried out at -80 kPa, followed by filtration, cooling to room temperature, uniform coating on a nonwoven fabric substrate by a doctor blade system, and entering a coagulation bath. The DMF aqueous solution having a mass fraction of 1.0% was at a temperature of 20 ° C; then it was placed in deionized water at a temperature of 20 ° C, and after 200 s of treatment, a support layer was obtained.

(3) Preparation of desalting layer: the support layer prepared in the step (2) was immersed in deionized water for 30 min, and the support layer was taken out from the deionized water, and contained with 2.5% by weight of m-phenylenediamine, 2.5 wt% of three-ethyl An aqueous solution of amine, 2.5 wt% benzyltriethylammonium chloride is contacted for 50 s to allow the aqueous phase solution to penetrate into the pores of the support layer; the excess aqueous solution is filtered off, and the aqueous phase droplets on the surface of the membrane are moved by a rolling rubber roller. In addition, the membrane was immersed in a solvent solution of n-hexane, cyclohexane mass ratio 1:1, and containing 0.06 wt% metal organic framework nanomaterial and 1 wt% isophthalic acid chloride for 45 s, and then the membrane was taken out. 2.0wt% dilute hydrochloric acid was washed, the cleaning time was 5min, then placed in 8.0wt% glycerin aqueous solution, glycerin temperature 60°C, infiltration time 5min, finally, the prepared metal organic frame reverse osmosis membrane was in 75°C oven Drying, you get the SWRO-MOFs-3 reverse osmosis membrane.

In the step (3), the preparation ratio of the support layer to the aqueous phase solution and the oil phase solution is 100 g: 5 L: 5 L.

Example 4

(2) Preparation of support layer: 4 wt% polyvinylpyrrolidone and N,N-dimethylformamide (DMF) were mixed and dispersed, and stirred at a stirring speed of 80 r/min to make polyvinylpyrrolidone in N , N-dimethylformamide (DMF) solution was uniformly dispersed, the stirring speed was maintained to 90 ° C, 19 wt% polyethersulfone was added thereto, and the remainder was supplemented with N,N-dimethylformamide (DMF). 100wt%, the solution for preparing the support layer is obtained, and then vacuum defoaming treatment is carried out at -80 kPa, filtered, cooled to room temperature, uniformly coated on the non-woven substrate by a doctor blade system and entered into a coagulation bath, and the coagulation bath is of mass. A 1.0% aqueous solution of DMF was applied at a temperature of 20 ° C; then it was placed in deionized water at a temperature of 20 ° C. After 200 s of treatment, a support layer was obtained.

(3) Preparation of desalting layer: the support layer prepared in the step (2) was immersed in deionized water for 30 min, and the support layer was taken out from the deionized water, and contained with 4 wt% of m-phenylenediamine, 4 wt% of triethylamine, The aqueous phase solution of 4wt% dodecyltrimethylammonium chloride is contacted for 55s to allow the aqueous phase solution to penetrate into the pores of the support layer; the excess aqueous solution is filtered out, and the aqueous phase droplets on the surface of the membrane are removed by rolling rubber rollers. The membrane was immersed in a solvent solution containing cyclohexane and n-heptane in a mass ratio of 1:1, and containing 0.08 wt% of metal organic framework nanomaterial and 2 wt% of 4,4'-diphenyldichloride chloride for 50 s. The membrane was taken out and washed with 2.0 wt% dilute hydrochloric acid for 5 min, then placed in a 8.0 wt% aqueous solution of glycerin, the glycerin temperature was 60 ° C, and the infiltration time was 5 min. Finally, the prepared metal organic frame reverse osmosis membrane was prepared. Drying in an oven at 80 ° C gives the SWRO-MOFs-4 reverse osmosis membrane.

In the step (3), the preparation ratio of the support layer to the aqueous phase solution and the oil phase solution is 100 g: 6 L: 5 L.

Example 5

(1) Preparation of metal organic framework nanomaterials: silver nitrate and N,N-dimethylformamide (DMF) were ultrasonically dispersed for 10 min at a mass ratio of 1:38, and trimesic acid and N,N-dimethyl The base formamide (DMF) was ultrasonically dispersed for 10 min at a mass ratio of 1:38, and the mixture was ultrasonicated for 1 h, centrifuged and filtered, and the obtained solid was washed with a mixture of water and ethanol (V water: V ethanol = 1:1). After drying at 60 ° C for 24 h, the resulting metal organic framework nanomaterial was retained for use in a vacuum desiccator.

(2) Preparation of support layer: 5 wt% polyvinylpyrrolidone and N,N-dimethylformamide (DMF) were mixed and dispersed, and stirred at a stirring speed of 90 r/min to make polyvinylpyrrolidone in N , N-dimethylformamide (DMF) solution was uniformly dispersed, maintaining the stirring speed to 90 ° C, adding 20 wt% polyethersulfone, and the remainder was supplemented with N,N-dimethylformamide (DMF). 100wt%, the solution for preparing the support layer is obtained, and then vacuum defoaming treatment is carried out at -80 kPa, filtered, cooled to room temperature, uniformly coated on the non-woven substrate by a doctor blade system and entered into a coagulation bath, and the coagulation bath is of mass. A 1.0% aqueous solution of DMF was applied at a temperature of 20 ° C; then it was placed in deionized water at a temperature of 20 ° C. After 200 s of treatment, a support layer was obtained.

(3) Preparation of desalting layer: the support layer prepared in the step (2) is immersed in deionized water for 30 min, the support layer is taken out from the deionized water, and contains 5 wt% of m-phenylenediamine, 5 wt% of triethylamine, 5wt% aqueous solution of tetrabutylammonium chloride is contacted for 60s, so that the aqueous phase solution penetrates into the pores of the support layer; the excess aqueous solution is filtered out, and the aqueous phase droplets on the surface of the membrane are removed by rolling rubber roller; Immersed in an oil phase solution containing n-hexane, n-heptane, Isopar G at a mass ratio of 1:1:1, and containing 0.1 wt% of metal organic framework nanomaterials and 3 wt% of trimesoyl chloride for 60 s, and then taken out the membrane with 2.0. The wt% diluted hydrochloric acid was cleaned for 5 min, then placed in a 8.0 wt% aqueous solution of glycerin, the glycerin temperature was 60 ° C, and the infiltration time was 5 min. Finally, the prepared metal organic frame reverse osmosis membrane was baked in an oven at 90 ° C. Dry, that is, SWRO-MOFs-5 reverse osmosis membrane.

In the step (3), the preparation ratio of the support layer to the aqueous phase solution and the oil phase solution is 100 g: 6 L: 6 L.

Comparative example 1

A method for preparing a reverse osmosis membrane, comprising the steps of:

(1) Preparation of support layer: 5 wt% polyvinylpyrrolidone and N,N-dimethylformamide (DMF) were mixed and dispersed, and stirred at a stirring speed of 90 r/min to make polyvinylpyrrolidone in N , N-dimethylformamide (DMF) solution was uniformly dispersed, maintaining the stirring speed to 90 ° C, adding 18 wt% polysulfone, and the remainder was supplemented with N,N-dimethylformamide (DMF) to 100 wt. %, the solution for preparing the support layer is obtained, and then vacuum defoaming treatment is carried out at -80 kPa, filtered, cooled to room temperature, uniformly coated on the non-woven substrate by a doctor blade system, and entered into a coagulation bath, and the coagulation bath is a mass fraction. It was a 1.0% aqueous solution of DMF at a temperature of 20 ° C; it was then placed in deionized water at a temperature of 20 ° C. After 200 s of treatment, a support layer was obtained.

(2) Preparation of desalting layer: the support layer prepared in the step (1) was immersed in deionized water for 30 min, and the support layer was taken out from the deionized water, and contained with 3 wt% of m-phenylenediamine, 4 wt% of triethylamine, 2wt% aqueous solution of benzyltriethylammonium chloride is contacted for 40s, so that the aqueous phase solution penetrates into the pores of the support layer; the excess aqueous solution is filtered out, and the aqueous phase droplets on the surface of the membrane are removed by rolling rubber rollers; After the membrane was immersed in an oil phase solution containing Iwtar G as a solvent and containing 3 wt% of trimesoyl chloride for 60 s, the membrane was taken out and washed with 2.0 wt% of dilute hydrochloric acid for 5 min, and then placed at 8.0 wt% of glycerol. In the aqueous solution, the glycerin temperature is 60 ° C, the infiltration time is 5 min. Finally, the prepared reverse osmosis membrane is dried in an oven at 80 ° C to obtain a SWRO reverse osmosis membrane.

Test case

The SWRO-MOFs-1, SWRO-MOFs-2, SWRO-MOFs-3, SWRO-MOFs-4, SWRO-MOFs-5 and SWRO of Examples 1-5 and Comparative Example 1 were placed in a reverse osmosis membrane test bench. The test was carried out by rinsing with pure water at a working pressure of 500 psi for 15 min and then switching to a 32,000 ppm NaCl aqueous solution as raw water. The temperature was controlled at 25 ° C, the pH was 6.4-7.3, and the pressure was 800 psi. The performance of the reverse osmosis membrane was tested after 30 min. The thickness of each reverse osmosis membrane was recorded, and the results are shown in Table 1.

Table 1. Comparison of performance between modified SWRO-MOFs diaphragm and unmodified reverse osmosis membrane

From the data shown in Table 1 above, the water flux of the seawater desalination reverse osmosis membrane prepared by the prior art is greatly improved compared with the prior art, and the salt rejection rate is almost unchanged, and the flux is greatly reduced. The energy consumption during the application of the reverse osmosis membrane prolongs the service life of the reverse osmosis membrane, and the present disclosure reduces the behavior of the membrane flux and the desalination rate to a certain extent, with significant progress and outstanding substantiality. feature.

Claims

A metal organic framework reverse osmosis membrane characterized in that the support layer is synthesized by a polymer and an active hydrophilic stabilizer, the aqueous phase solution comprises a catalyst and an aqueous phase monomer, and the oil phase solution comprises a metal organic framework nano material and an oil phase single The desalting layer on the support layer is a functional layer of the support layer formed by the interfacial polymerization of the aqueous phase solution and the oil phase solution to form a crosslinked nanocrystal network structure.
The metal organic framework reverse osmosis membrane according to claim 1, wherein the polymer is one of polysulfone or polyethersulfone, and the concentration in the solution for preparing the support layer is from 16% by weight to 20% by weight.
The metal organic framework reverse osmosis membrane according to claim 1, wherein the active hydrophilic stabilizer is polyvinylpyrrolidone having a concentration of 0.15 wt% to 5 wt% in the solution for preparing the support layer.
The metal organic framework reverse osmosis membrane according to claim 2 or 3, wherein the solution for preparing the support layer is a solvent of N,N-dimethylformamide (DMF), except for the polymer and the activity. The portion other than the hydrophilic stabilizer was supplemented with N,N-dimethylformamide (DMF) to 100% by weight.
The metal organic framework reverse osmosis membrane according to claim 1, wherein said catalyst is a mixture of a phase transfer catalyst and an acid binding agent; wherein the phase transfer catalyst is tetrabutylammonium chloride or triethylamine salt. One of the acid salt, benzyltriethylammonium chloride and dodecyltrimethylammonium chloride in the aqueous phase solution is from 0.5% by weight to 5.0% by weight; the acid binding agent is three The concentration of the amine in the aqueous phase solution is from 0.5% by weight to 5.0% by weight.
The metal organic framework reverse osmosis membrane according to claim 1, wherein the aqueous phase monomer is m-phenylenediamine, and the concentration in the aqueous phase solution is from 0.5% by weight to 5.0% by weight.
The metal organic framework reverse osmosis membrane according to claim 1, wherein the metal organic framework nano material is composed of silver ions and trimesic acid, and the mass ratio is 1:1, and the active functional group is a carboxyl group. The concentration in the oil phase solution is from 0.02% by weight to 0.1% by weight.
The metal organic framework reverse osmosis membrane according to claim 1, wherein the oil phase monomer is phthaloyl chloride, terephthaloyl chloride, isophthaloyl chloride, 4,4'-linked. One of phthaloyl chloride and trimesoyl chloride has a concentration in the oil phase solution of 0.005 wt% to 3 wt%.
The metal organic framework reverse osmosis membrane according to claim 1, wherein the oil phase solution has a solvent of one or more of n-hexane, cyclohexane, n-heptane and Isopar G.
A method for preparing a metal organic framework reverse osmosis membrane, comprising the steps of:

(1) Preparation of metal organic framework nanomaterials: silver nitrate and N,N-dimethylformamide (DMF) were ultrasonically dispersed for 10 min at a mass ratio of 1:38, and trimesic acid and N,N-dimethyl The base formamide (DMF) was ultrasonically dispersed for 10 min at a mass ratio of 1:38, and the mixture was ultrasonicated for 1 h, centrifuged and filtered, and the resulting precipitate was washed with a mixture of water and ethanol (V water: V ethanol = 1:1). ~5 times, drying at 60 ° C for 24h, the resulting metal organic framework nanomaterials are retained in the vacuum dryer until use;

(2) Preparation of support layer: 0.15 wt% to 5 wt% of polyvinylpyrrolidone and N,N-dimethylformamide (DMF) are mixed and dispersed, and stirred at a stirring speed of 60-90 r/min. The polyvinylpyrrolidone is uniformly dispersed in a solution of N,N-dimethylformamide (DMF), the stirring speed is maintained to 90 ° C, and a polymer having a mass concentration of 16 wt% to 20 wt% is added thereto, and the balance is N. N-dimethylformamide (DMF) was added to 100% to obtain a solution for preparing a support layer, followed by vacuum defoaming treatment at -80 kPa, followed by filtration, cooling to room temperature, and coating the solution on a nonwoven fabric base. The material enters the coagulation bath and is then placed in deionized water for 200 s to obtain a support layer;

(3) Preparation of desalting layer: the support layer prepared in the step (2) is immersed in deionized water for 30 min, and the support layer is taken out from the deionized water, and contains 0.5 wt% to 5 wt% of m-phenylenediamine, 0.5 wt. The aqueous solution of %~5wt% triethylamine and 0.5wt%~5wt% phase transfer catalyst is contacted for 40s~60s, so that the aqueous phase solution penetrates into the pore of the support layer; the excess aqueous solution is filtered, and the aqueous phase liquid on the surface of the membrane is filtered. The droplet is removed by a rolling rubber roller; the membrane is immersed in the oil phase solution for 30 s to 60 s, and the oil phase solution contains 0.02 wt% to 0.1 wt% of the metal organic framework nanomaterial and 0.005 wt% to 3 wt% of phthaloyl chloride, One of phthaloyl chloride, isophthalic acid chloride, phthaloyl dichloride, and trimesoyl chloride. The membrane was taken out and washed with dilute hydrochloric acid for 5 min, infiltrated with glycerin aqueous solution for 5 min, and placed in an oven at 30 ° C to 90 ° C. Drying in the middle, that is.