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CN-121988184-A - Functionalized polydopamine modified mixed matrix membrane and preparation method and application thereof

CN121988184ACN 121988184 ACN121988184 ACN 121988184ACN-121988184-A

Abstract

The invention relates to a functionalized polydopamine modified mixed matrix membrane, a preparation method and application thereof, wherein the mixed matrix membrane is immersed into a dopamine solution, then immersed into a modifying agent solution for improving hydrophobicity, ultrasonic reaction is carried out during immersion, vacuum drying is carried out, and modified polydopamine is coated on the surface of the mixed matrix membrane, wherein the modifying agent is one or more selected from 1H, 2H-perfluoro decyl triethoxysilane, 1H, 2H-perfluoro decyl trichlorosilane and 1-dodecanethiol. Compared with the prior art, the invention improves the selectivity and the stability of the membrane and effectively solves the problems of stability and treatment efficiency of the mixed matrix membrane in the separation process.

Inventors

  • MENG FANMAO
  • LI XINLE
  • WANG HANLIN
  • XIAO YUE
  • LIU HENGZHI

Assignees

  • 中石油(上海)新材料研究院有限公司
  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241101

Claims (10)

  1. 1. The functional polydopamine modified mixed matrix membrane is characterized in that the mixed matrix membrane is immersed into a dopamine solution firstly, then immersed into a modifying agent solution for improving hydrophobicity, subjected to ultrasonic reaction and vacuum drying during immersion, and the surface of the mixed matrix membrane is coated with modified polydopamine; The modifier is one or more selected from 1H, 2H-perfluoro decyl triethoxysilane, 1H, 2H-perfluoro decyl trichlorosilane and 1-dodecanethiol.
  2. 2. A method of preparing the functionalized polydopamine modified mixed matrix membrane according to claim 1, comprising the steps of: s1, preparing a high molecular organic polymer solution, adding a dispersing agent into the high molecular organic polymer solution, adding a metal organic framework material into the high molecular organic polymer solution after the dispersing agent is dissolved, continuously mixing, and finally performing ultrasonic treatment to obtain a casting solution; casting the casting film, standing for film forming, and vacuum drying to obtain a mixed matrix film; s2, dissolving dopamine in a buffer solution to obtain a dopamine-buffer solution; s3, ultrasonically wetting the mixed matrix membrane, immersing the mixed matrix membrane into a dopamine-buffer solution, performing ultrasonic reaction for coating, taking out the composite mixed matrix membrane, and drying in vacuum; S4, immersing the composite mixed matrix membrane into a modifier solution, performing ultrasonic reaction for modification, taking out the modified composite mixed matrix membrane, and performing vacuum drying to obtain the functional polydopamine modified mixed matrix membrane.
  3. 3. The method for preparing the functionalized poly-dopamine modified mixed matrix membrane according to claim 2, wherein in the step S1, the high molecular organic polymer is selected from one or more of polyvinyl chloride, polyvinylidene fluoride, polyethylene terephthalate, polyimide and polyacrylonitrile, and the solvent of the high molecular organic polymer solution is selected from one or more of N, N-dimethylformamide, acetone and N-methylpyrrolidone, and the mass concentration is 0.1-0.5g/mL; the temperature is 40-80 ℃ and the time is 0.5-5h.
  4. 4. The method for preparing the functionalized polydopamine modified mixed matrix membrane according to claim 2, wherein in the step S1, the dispersing agent is selected from one or more of polyethylene glycol, polyvinyl alcohol and sodium polyacrylate, and the mass ratio of the dispersing agent to the high molecular organic polymer is (0.05-0.5): 1; the dissolution temperature is 40-80 ℃ and the time is 0.5-3h.
  5. 5. The method for preparing the functionalized poly-dopamine modified mixed matrix membrane according to claim 2, wherein in the step S1, the metal-organic framework material is selected from one or more of MAF-2, MAF-6, FMOF-1, MIL-101, MIL-53, ZIF-8, ZIF-67, ZIF-71 and ZIF-L, and the mass ratio of the metal-organic framework material to the high molecular organic polymer is (0.01-1): 1; Mixing at 40-80deg.C for 1-5 hr; the frequency of ultrasonic treatment is 100-500Hz, the temperature is 10-40 ℃ and the time is 0.5-5h; the temperature of vacuum drying is 40-80 ℃, the vacuum degree is 5-40kPa, and the time is 24-72 hours.
  6. 6. The method for preparing the functionalized polydopamine modified mixed matrix membrane according to claim 2, wherein the buffer solution in the step S2 is a tris-hydrochloric acid buffer solution, the pH of the buffer solution is 8-9, and the molar concentration of the buffer solution is 0.05-0.15mol/L; the mass concentration of the dopamine in the dopamine solution is 0.1-10g/L; The dissolution temperature is 10-40deg.C, and the dissolution time is 1-30min.
  7. 7. The method for preparing the functionalized polydopamine modified mixed matrix membrane according to claim 2, wherein the ultrasonic wetting frequency in the step S3 is 100-500Hz, the temperature is 10-40 ℃ and the time is 0.5-3h; The frequency of the ultrasonic reaction is 100-500Hz, the temperature is 10-100 ℃ and the time is 2-24h; the temperature of vacuum drying is 40-80 ℃, the vacuum degree is 5-40kPa, and the time is 6-24 hours.
  8. 8. The method for preparing a functionalized polydopamine modified mixed matrix membrane according to claim 2, wherein the solvent of the modifier solution in step S4 is one or more selected from cyclohexane, n-hexane and isopentane, and the mass concentration is 1-15g/L; The frequency of the ultrasonic reaction is 100-500Hz, the temperature is 10-40 ℃ and the time is 0.5-5h; the temperature of vacuum drying is 40-80 ℃, the vacuum degree is 5-40kPa, and the time is 6-24 hours.
  9. 9. Use of the functionalized polydopamine modified mixed matrix membrane according to claim 1, wherein the membrane is applied for the separation of toluene/water systems.
  10. 10. The use of a functionalized polydopamine modified mixed matrix membrane according to claim 9 wherein the toluene content of the toluene/water system mixture is 100-1000ppm and the feed temperature is 20-70 ℃.

Description

Functionalized polydopamine modified mixed matrix membrane and preparation method and application thereof Technical Field The invention belongs to the technical field of membrane separation, and relates to a functionalized polydopamine modified mixed matrix membrane, and a preparation method and application thereof. Background In daily production in the fields of chemical industry, medicine, environmental engineering and the like, more industrial wastewater containing toluene is usually generated, wherein toluene is one of volatile organic matters with carcinogenicity and toxicity, and even at extremely low concentration, the toluene can harm human health, and meanwhile, water pollution is an increasingly serious environmental problem. Therefore, a filter material and a filter technology capable of efficiently treating industrial wastewater containing toluene have been attracting attention. The membrane separation technology has the advantages of low energy consumption, simple and convenient operation, easy mass production and the like, and the microstructure of the membrane can be well controlled by different methods, so the membrane separation technology is considered as one of high-efficiency separation methods for removing pollutants in water. In recent years, the mixed matrix membrane (Mixed Matrix Membranes, MMMs) has become a separation material with application prospects due to the combination of the advantages of inorganic filler materials and organic polymers. The membrane can overcome the defects of low separation performance of a pure polymer membrane and high cost of an inorganic membrane, but still has the problems of interfacial compatibility between an inorganic filler and an organic polymer matrix and stability of a mixed matrix membrane, especially the problem that the service life of the obtained mixed matrix membrane is limited by the water stability of part of metal-organic framework (MOF) materials, and besides, the surface of the hydrophobic separation membrane is easy to generate certain membrane pollution, so that the membrane performance is reduced, and the service life of a membrane layer is finally influenced. Patent CN115245760A discloses a preparation method of an emergency drinking nanofiltration purification membrane, which comprises the steps of taking polyvinylidene fluoride, dopamine hydrochloride, polyethylenimine and quaternized polyethylenimine, adding dimethylacetamide, mixing and stirring to obtain a casting solution, taking the casting solution, vacuum filtering and defoaming, uniformly scraping the casting solution onto the surface of a non-woven fabric, placing the non-woven fabric in a coagulating bath, carrying out water bath oscillation reaction to obtain a support membrane, taking m-phenylenediamine and deionized water, uniformly stirring to obtain a water phase solution, taking trimesoyl chloride and n-hexane, uniformly mixing, adding acyl chlorinated graphene oxide, carrying out ultrasonic dispersion to obtain an oil phase solution, soaking the support membrane in the water phase solution, taking out, standing and airing the support membrane, placing the support membrane in the oil phase solution, reacting the support membrane, taking out, standing, drying, and washing the support membrane with deionized water to obtain the purification membrane. However, the patent is a hydrophilic organic separation membrane, has obvious Trade-off effect between separation performance and cost, and has poor selectivity and chemical stability in a toluene/water separation system. The patent CN114307693A discloses a preparation method of a MOFs/PDA composite fiber gas separation membrane, which adopts an electrostatic spinning technology to prepare MOFs nanofiber mats, uses dopamine as a filling polymer micromolecule, firstly places the MOFs nanofiber mats in a dopamine solution, uses a Tris-HCl buffer solution to regulate the pH value, places the MOFs nanofiber mats at room temperature, takes out the MOFs nanofiber mats, uses deionized water and ethanol to sufficiently oscillate and clean the MOFs/PDA composite fiber mats, replaces the dopamine hydrochloride solution, repeatedly soaks the MOFs/PDA composite fiber mats for a plurality of times, then carries out vacuum drying to obtain a fully polymerized MOFs/PDA composite fiber gas separation membrane, uses polyethylene glycol diacrylate as a filling polymer micromolecule, adds a photoinitiator 1-hydroxycyclohexyl phenyl ketone into the polyethylene glycol diacrylate to prepare a polymer filling liquid, carries out uniform stirring in a light-resistant environment, then carries out ultrasonic defoaming on the filling liquid to discharge bubbles, then places the MOFs nanofiber mats in an ultrafiltration cup, adds the polymer filling liquid into the ultrafiltration cup, and finally carries out photopolymerization in an argon environment to obtain the fully cured MOFs/PDA composite fiber gas separation membrane. However, this p