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CN-122006524-A - Janus structure hollow fiber loose nanofiltration membrane and preparation method and application thereof

CN122006524ACN 122006524 ACN122006524 ACN 122006524ACN-122006524-A

Abstract

The invention provides a Janus structure hollow fiber loose nanofiltration membrane and a preparation method and application thereof, wherein the Janus structure hollow fiber loose nanofiltration membrane uses piperazine as an inner water phase monomer of the membrane and polyethylene imine as an outer water phase monomer of the membrane, and is matched with an isophthaloyl dichloride organic phase monomer, so that a Janus structure polyamide functional layer can be accurately constructed through inner and outer step-by-step interfacial polymerization, differential regulation and control of charge properties inside and outside the membrane can be realized, and meanwhile, phenyl trimethyl ammonium chloride is specifically added into an inner interfacial polymerization water phase solution of the membrane, so that a uniform and compact interfacial polymerization layer can be formed inside the membrane, the hydrophilicity of the membrane can be obviously improved, the permeation flux of the membrane can be further optimized, and the problems of uneven interfacial polymerization layer, poor hydrophilicity and low flux of the conventional hollow fiber nanofiltration membrane are solved.

Inventors

  • WANG JIE
  • WU JIALIN
  • GAO FEI
  • JIA HUI
  • SHU CHANG

Assignees

  • 天津工业大学

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. 1. The preparation method of the Janus structure hollow fiber loose nanofiltration membrane is characterized by comprising the following steps of: S1, preparing a hollow fiber ultrafiltration base membrane by adopting a phase inversion method; s2, weighing piperazine and phenyl trimethyl ammonium chloride, adding water for dissolving to obtain an inner-layer aqueous phase solution, introducing the inner-layer aqueous phase solution into the membrane prepared in the S1 through a peristaltic pump, and removing the redundant inner-layer aqueous phase solution on the inner surface of the membrane by adopting nitrogen blowing after the membrane stays for 5-10 min; S3, dissolving isophthaloyl dichloride in n-hexane to obtain an organic phase solution, introducing the organic phase solution into the membrane treated in the S2 for interfacial polymerization reaction, removing the excessive organic phase solution after the reaction is finished, and drying for later use after natural volatilization; S4, weighing polyethylenimine, adding water to dissolve to obtain an outer layer aqueous phase solution, sealing two ends of the membrane treated in the S3, immersing the membrane in the outer layer aqueous phase solution, and removing redundant outer layer aqueous phase solution on the surface of the membrane component after the membrane stays for 5-8 min; S5, immersing the membrane treated in the S4 into an organic phase solution containing isophthaloyl dichloride for external interfacial polymerization reaction, removing redundant organic phase solution after the reaction is finished, and drying after the membrane is naturally volatilized to obtain the Janus structure hollow fiber loose nanofiltration membrane.
  2. 2. The method for preparing a porous nanofiltration membrane with a Janus structure hollow fiber according to claim 1, wherein the hollow fiber ultrafiltration base membrane in S1 is made of polyethersulfone or polysulfone.
  3. 3. The method for preparing a porous nanofiltration membrane with Janus structure hollow fiber according to claim 1, wherein the mass concentration of piperazine in the inner layer aqueous phase solution of S2 is 0.1-0.4wt%, the mass concentration of phenyltrimethylammonium chloride is 0.03-0.06wt%, and the mass concentration ratio of piperazine to phenyltrimethylammonium chloride is 10 (1-3).
  4. 4. The method for preparing a porous nanofiltration membrane with Janus structure hollow fiber according to claim 1, wherein the mass concentration of isophthaloyl dichloride in the organic phase solution of S3 and S5 is 0.15wt%.
  5. 5. The method for preparing a porous nanofiltration membrane with a Janus structure hollow fiber according to claim 1, wherein the interfacial polymerization reaction time in S3 is 60-120S.
  6. 6. The method for preparing a porous nanofiltration membrane with Janus structure hollow fiber according to claim 1, wherein the flow rate of the solution passing process in the membranes of S2 and S3 is 10ml/min.
  7. 7. The method for preparing the Janus structure hollow fiber loose nanofiltration membrane according to claim 1, wherein the mass concentration of the polyethyleneimine in the outer layer aqueous phase solution of the S4 is 0.2-0.4wt%.
  8. 8. The method for preparing a porous nanofiltration membrane with a Janus structure hollow fiber according to claim 1, wherein the interfacial polymerization reaction time in S5 is 120-180S.
  9. 9. A Janus structured hollow fiber porous nanofiltration membrane prepared by the preparation method of any one of claims 1 to 8.
  10. 10. The application of the Janus structure hollow fiber porous nanofiltration membrane as claimed in claim 9 in the field of printing and dyeing wastewater treatment is characterized in that the Janus structure hollow fiber porous nanofiltration membrane is applied to separation of dye and salt in the printing and dyeing wastewater treatment.

Description

Janus structure hollow fiber loose nanofiltration membrane and preparation method and application thereof Technical Field The invention belongs to the technical field of membrane separation, and particularly relates to a Janus structure hollow fiber loose nanofiltration membrane, and a preparation method and application thereof. Background In the fabric dyeing process, in order to promote the absorption of the dye by the fiber, inorganic salts such as sodium chloride with the mass fraction of 1-6% and sodium sulfate with the mass fraction of 0.5-5% are generally required to be introduced, so that the coexistence of the dye and salt ions is commonly caused in the printing and dyeing wastewater. The efficient separation of the organic dye and the inorganic salt ion mixture is realized, the method is not only the key of standard treatment of printing and dyeing wastewater, but also has important practical significance for recycling valuable substances in water and improving the resource utilization rate. Nanofiltration membrane technology shows remarkable application advantages in the dye/salt separation field by virtue of the unique separation performance, and becomes one of the core technical directions of the field. However, the existing commercial nanofiltration membrane generally shows higher retention rate on dye and inorganic salt, is difficult to realize effective separation of the dye and the inorganic salt, severely limits the resource recovery efficiency, and cannot meet the actual requirements of the printing and dyeing wastewater recycling treatment. The porous nanofiltration membrane can realize the selective permeation of inorganic salt and the high-efficiency interception of dye molecules, and provides a feasible technical path for the accurate separation of dye/salt, so that the porous nanofiltration membrane has wide application prospect in the field of printing and dyeing wastewater treatment. At present, a main preparation mode of the nanofiltration membrane is that a flat base membrane is used as a support body, and an ultrathin polyamide functional layer is formed by interfacial polymerization reaction of a water phase polyamine monomer and an oil phase polybasic acyl chloride monomer on the surface of the base membrane. However, since the interfacial polymerization reaction rate between monomers is high, the growth process of the polyamide layer is difficult to accurately regulate, so that the prepared nanofiltration membrane has the defects of compact structure, low water flux, poor separation selectivity and the like, and the efficiency is low in dye/salt separation application, and the actual treatment requirements cannot be met. Compared with traditional membrane components such as a flat membrane and a rolled membrane, the hollow fiber membrane has the remarkable advantages of high packing density per unit volume, no need of additional supporting bodies for integrated components, large effective filtering area, small occupied area, relatively low preparation and operation cost and the like, and meets the requirements of industrial large-scale application. However, due to the influence of the curvature structure of the hollow fiber membrane, a uniform interfacial polymerization functional layer is difficult to form on the surface of the hollow fiber membrane, and the application of the hollow fiber nanofiltration membrane in the dye/salt separation field is greatly limited. In conclusion, the research of the porous nanofiltration membrane which aims at efficiently separating dye/salt is still in the initial stage, the problems of high material cost, complex preparation process, large difficulty in regulating and controlling a functional layer, incapability of matching the separation performance with the actual application requirements and the like in the prior art generally exist, and meanwhile, the preparation technology of the hollow fiber porous nanofiltration membrane with excellent separation effect and industrial application potential has not been broken through. Therefore, the development of the preparation method of the hollow fiber loose nanofiltration membrane with simple and convenient process, controllable cost and excellent separation performance becomes a technical problem to be solved urgently in the current printing and dyeing wastewater recycling treatment field, and is also a research focus and core requirement of a person skilled in the art. Disclosure of Invention In view of the above, the invention aims to provide a Janus structure hollow fiber loose nanofiltration membrane, a preparation method and application thereof, and the prepared Janus structure hollow fiber loose nanofiltration membrane has good separation performance of dye and salt. In order to achieve the above purpose, the technical scheme of the invention is realized as follows: a preparation method of a Janus structure hollow fiber loose nanofiltration membrane comprises the following steps: S1, pre