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CN-121988193-A - Preparation method of reverse osmosis membrane with high desalination rate and high selectivity

CN121988193ACN 121988193 ACN121988193 ACN 121988193ACN-121988193-A

Abstract

The invention discloses a preparation method of a reverse osmosis membrane with high desalination rate and high selectivity, wherein a nonionic surfactant polyethylene glycol monolauryl ether capable of reacting with trimesoyl chloride is introduced into an organic phase, a newly generated monomer has the performance of a surfactant, a monomolecular layer aggregate can be formed at a two-phase interface, acyl chloride groups in the trimesoyl chloride and ether oxygen groups in the new monomer are both polar groups and promote the aggregation of amine monomers at the phase interface under the action of high dipole moment, and meanwhile, the new monomer generated by the reaction of the nonionic surfactant and the trimesoyl chloride in the organic phase can promote the reaction of the trimesoyl chloride and the amine monomers and can react with the amine monomers to fill a low-selection area in a separation layer. The preparation method is simple, easy to amplify, does not change the existing reverse osmosis preparation flow, and is easy to directly produce on the existing production line.

Inventors

  • YAN SHUAI
  • CHENG BIN
  • KANG YAN
  • WU ZONGCE
  • GUO YUYANG

Assignees

  • 沃顿科技股份有限公司

Dates

Publication Date
20260508
Application Date
20241104

Claims (8)

  1. 1. A preparation method of a reverse osmosis membrane with high desalination rate and high selectivity is characterized by comprising the following steps, Step 1, preparing a water phase solution, adding an amine monomer, camphorsulfonic acid, triethylamine and sodium dodecyl sulfate into deionized water, and uniformly stirring to obtain the water phase solution; Step 2, preparing an organic phase solution, dissolving acyl chloride monomers in the organic solvent, adding a nonionic surfactant, and performing ultrasonic treatment for 30min to obtain the organic phase solution; Step 3, preparing a reverse osmosis membrane by interfacial polymerization, namely immersing the polysulfone ultrafiltration membrane in the aqueous phase solution prepared in the step 1, then taking out and removing water drops on the surface of the ultrafiltration membrane, immersing in the organic phase solution prepared in the step 2 for interfacial polymerization, and then taking out and standing for draining; Step 4, drying treatment, namely performing heat treatment on the film product obtained in the step 3; In step 2, a nonionic surfactant which can react with the monomer and can maintain the performance of the catalyst after the reaction is added into the organic phase solution, and a separation layer with high crosslinking and reasonable stacking is realized on the support. The nonionic surfactant is at least one of polyethylene glycol monolauryl ether and Tween 80.
  2. 2. The method for producing a high desalination rate and high selectivity reverse osmosis membrane according to claim 1, wherein the concentration of the nonionic surfactant added to the organic phase solution is 0.002wt%, 0.004wt%, 0.006wt%, 0.008wt%, 0.01wt% and 0.02wt%, respectively.
  3. 3. The method for producing a reverse osmosis membrane according to claim 1, wherein the amine monomer in step 1 is at least one of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine and biphenyldiamine, preferably m-phenylenediamine, and the concentration of the amine monomer in the aqueous solution is 1 to 3wt%, the concentration of camphorsulfonic acid is 2 to 4wt%, the concentration of triethylamine is 1 to 2wt%, and the concentration of sodium dodecyl sulfate is 0.05 to 0.5wt%.
  4. 4. The method for preparing a reverse osmosis membrane with high desalination rate and high selectivity according to claim 1, wherein the organic solvent in the step 2 is one of n-hexane, cyclohexane, n-heptane and Isopar G, preferably cyclohexane, the acyl chloride monomer is trimesoyl chloride, and the concentration of trimesoyl chloride in the organic phase is 0.1-0.3wt%.
  5. 5. The method for preparing a reverse osmosis membrane with high desalination rate and high selectivity according to claim 1, wherein the infiltration time of the aqueous solution on the surface of the polysulfone ultrafiltration membrane in the step 3 is 0.5-3min, and the interfacial polymerization reaction time is 30-60s.
  6. 6. The method for producing a reverse osmosis membrane according to claim 1, wherein the means for removing water droplets in the step 3 is an air knife, and the drying treatment in the step 4 is carried out in a blow drying oven.
  7. 7. The method for producing a reverse osmosis membrane with high desalination rate and high selectivity according to claim 1, wherein the temperature of the air drying oven in step 4 is 85-95 ℃, preferably 90 ℃ and the drying time is 5min.
  8. 8. The method for producing a reverse osmosis membrane according to claim 1, wherein the nonionic surfactant is preferably polyethylene glycol monododecyl ether.

Description

Preparation method of reverse osmosis membrane with high desalination rate and high selectivity Technical Field The invention belongs to the technical field of reverse osmosis membranes, and particularly relates to a preparation method of a reverse osmosis membrane with high desalination rate and high selectivity. Background Along with the continuous deterioration of global fresh water resources and the continuous increase of the demand for high-quality water, the reverse osmosis technology is used as an efficient and stable water treatment method and is widely applied to the fields of sea water desalination, wastewater treatment, ultrapure water preparation and the like. The aromatic polyamide reverse osmosis membrane has the advantages of large flux, high rejection rate, wide operating temperature, good chemical stability, wide pH working range and the like, and becomes the most applied reverse osmosis membrane in the global water treatment industry. However, with the application of reverse osmosis membranes in the subdivision industries of household water purification, electronic industry ultra-pure water preparation, domestic sewage reuse, industrial wastewater zero discharge and the like, demands for reverse osmosis membranes with high desalination rate and high selectivity have been rapidly increased. The prior researches show that the reverse osmosis membrane with high desalination rate or high selectivity can be prepared through the development of an interfacial polymerization process and the post-treatment of the reverse osmosis membrane. Despite the advances made in these methods, there are still some problems. First, the development of interfacial polymerization has limited improvement in membrane desalination rate or membrane selectivity. Although the desalination rate or selectivity of the membrane is improved to some extent, the amplitude of the improvement is lower. Further, due to the trade-off effect of reverse osmosis membrane water flux and desalination rate, the improvement of desalination rate or selectivity is generally accompanied by a significant decrease in water flux. Second, the post-processing process is time consuming and complex. The post-treatment involves additional steps such as gel preparation, long grafting times on the membrane surface, long compound permeation, etc., and it is difficult to industrially perform these complicated and time-consuming operations. Fundamentally, the rejection rate and selectivity of a membrane depend on the reaction and diffusion of the reactive monomers during interfacial polymerization. Since interfacial polymerization occurs in very small areas, it is difficult to precisely regulate this rapid reaction-diffusion process using existing methods. Thus, during interfacial polymerization, the reaction and diffusion of monomers in the aqueous and organic phases often deviate from ideal conditions, severely hampering the preparation of highly crosslinked separation layer molecules. Furthermore, the separation layer is formed by random stacking of rigid molecules, and a region of low selectivity exists in the separation layer. In view of the problems of formation and reasonable stacking of highly crosslinked separation layer molecules that have not been fully solved by previous studies, it remains a challenge to develop a simple and efficient method for preparing reverse osmosis membranes with high desalination rates and high selectivity. The Chinese patent publication No. CN1114471C discloses a method for adsorbing and modifying the interfacial surfactant in a reverse osmosis composite membrane, wherein a nonionic surfactant is added into an aqueous phase solution, and the performance of the reverse osmosis composite membrane is improved through interfacial adsorption in the surfactant. The preparation method of the reverse osmosis membrane with the publication number of CN116139698B is to add a surfactant when preparing the water phase mixed solution, so as to prepare the novel reverse osmosis membrane with good separation performance, good pollution resistance and other specific functions. Both of the above methods introduce surfactants into the raw materials of the preparation process, but the modification of the composite membrane by the active agents does not play a critical role therein. The invention aims at the problems of Gao Jiaolian separation layer molecule formation and reasonable stacking, and develops a simple and efficient method for preparing the reverse osmosis membrane with high desalination rate and high selectivity. Disclosure of Invention In order to solve the above problems, the present invention aims to provide a method for preparing a reverse osmosis membrane having high desalination rate and high selectivity. In order to achieve the above object, the present invention adopts the following technical scheme that the preparation method of the reverse osmosis membrane with high desalination rate and high selectivity comprises