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CN-121988183-A - Composite separation membrane, preparation method and application thereof

CN121988183ACN 121988183 ACN121988183 ACN 121988183ACN-121988183-A

Abstract

The invention relates to the technical field of water treatment, in particular to a composite separation membrane, a preparation method and application thereof. The invention provides a composite separation membrane which comprises a base membrane and an active separation layer formed on the base membrane, wherein the active separation layer is formed by performing interfacial polymerization reaction on the base membrane by aqueous phase solution and oil phase solution, the aqueous phase solution comprises piperazine, a surfactant, a cosolvent, an amino-functionalized hydrogen bond organic framework and water, and the oil phase solution comprises hydroxylated imine cage powder, acyl chloride monomers and an organic solvent. The composite separation membrane provided by the invention has relatively high desalination rate and water flux.

Inventors

  • QI SAREN
  • Tao Naiyin
  • YU PUREN
  • ZHANG JINBAO
  • SHI CHUDAO

Assignees

  • 湖南沁森高科新材料有限公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (10)

  1. 1.A composite separation membrane is characterized by comprising a base membrane and an active separation layer formed on the base membrane; the active separation layer is formed by interfacial polymerization reaction of aqueous phase solution and oil phase solution on the base film; the aqueous phase solution comprises piperazine, a surfactant, a cosolvent, an amino-functionalized hydrogen bond organic framework and water; The oil phase solution comprises hydroxylated imine cage powder, acyl chloride monomer and organic solvent.
  2. 2. The composite separation membrane of claim 1, wherein the amino-functionalized hydrogen-bonded organic framework is prepared by introducing amino groups into the surface by post-synthesis modification.
  3. 3. The composite separation membrane of claim 1, wherein the method of preparing the amino-functionalized hydrogen bond organic framework comprises the steps of: Dispersing the hydrogen bond organic frame nanocrystalline in anhydrous toluene, and then carrying out reflux stirring reaction with (3-aminopropyl) triethoxysilane in a protective gas atmosphere to obtain the amino-functionalized hydrogen bond organic frame nanocrystalline.
  4. 4. A composite separation membrane according to claim 3, wherein the method of preparing hydrogen bonded organic framework nanocrystals comprises the steps of: Dissolving 1,3, 5-trimethyl phloroglucinol and 2, 5-diaminobenzene sulfonic acid in a mixed solvent of dimethylformamide and acetic acid, reacting at 110-130 ℃, performing post-treatment to obtain powder, performing ultrasonic crushing treatment on the powder in ethanol, and centrifuging to obtain ethanol dispersion of hydrogen bond organic frame nanocrystals.
  5. 5. The composite separation membrane according to claim 1, wherein in the aqueous phase solution, the mass content of piperazine is 0.6% -0.9%, the mass content of surfactant is 0.02% -0.03%, the mass content of cosolvent is 2% -5%, and the mass content of amino-functionalized hydrogen bond organic framework is 0.01% -0.1%; The surfactant is sodium cetyl sulfate.
  6. 6. The composite separation membrane of claim 1, wherein the preparation method of the hydroxylated imine cage powder comprises the following steps: s1, dropwise adding the solution b into the solution a under vigorous stirring, and stirring for reaction; the solution a is prepared by dissolving imine cage powder in anhydrous tetrahydrofuran under the condition of protective gas; The solution b is prepared by dissolving sodium borohydride in anhydrous tetrahydrofuran; S2, cooling the solution obtained after the stirring reaction in the step S1 to 20-30 ℃, dropwise adding methanol into the reaction solution while stirring to quench excessive sodium borohydride, exposing the reaction mixture to air after no obvious bubbles are generated, and continuously stirring at room temperature; s3, concentrating the reaction mixture after continuous stirring under reduced pressure, and dripping the obtained concentrated solution into water under vigorous stirring to precipitate solids, thereby obtaining the hydroxylated imine cage.
  7. 7. The composite separation membrane according to claim 1, wherein the oil phase solution contains 0.01-0.06% of hydroxylated imine cage powder and 0.15-0.25% of acyl chloride monomer by mass; the acyl chloride monomer is trimesoyl chloride; The organic solvent is n-hexane.
  8. 8. The composite separation membrane according to claim 1, wherein the thickness of the base membrane is 120-140 μm; The thickness of the active separation layer is 100-250 nm.
  9. 9. The method for preparing the composite separation membrane according to any one of claims 1 to 8, comprising the steps of: A. pretreating a base film; B. And C, soaking the base membrane treated in the step A in aqueous phase solution, taking out the surface of the base membrane, contacting with organic phase solution, performing interfacial polymerization reaction, and curing to form an active separation layer to obtain the composite separation membrane.
  10. 10. Use of a composite separation membrane according to any one of claims 1 to 8 or a composite separation membrane produced by the production method according to claim 9 in the field of water treatment.

Description

Composite separation membrane, preparation method and application thereof Technical Field The invention relates to the technical field of water treatment, in particular to a composite separation membrane, a preparation method and application thereof. Background The reverse osmosis membrane technology is an important technology for solving the problem of fresh water resource shortage and water resource pollution, and is widely applied to the fields of drinking water purification, wastewater treatment, industrial water treatment, seawater and brackish water desalination and the like. The reverse osmosis membrane commonly used in the market at present is a Polyamide (PA) composite membrane, which consists of three layers, namely a polyester non-woven fabric serving as a supporting structure, an ultrafiltration middle layer and a functional separation layer. The formation of a dense, nonporous separation layer by interfacial polymerization follows a "dissolution-diffusion" mechanism, with an inherent Trade-off relationship between water flux and salt rejection, a well-known "Trade-off" effect. In order to realize high desalination rate, the membrane is often made too dense, so that the water flux is low, and further, higher operation pressure is needed, thereby obviously improving the energy consumption of the system. Therefore, the development of the next generation separation membrane capable of simultaneously realizing ultrahigh water flux and high selectivity is a key for breaking through the bottleneck of the prior art and meeting the demands of the market on lower energy consumption and higher treatment efficiency. ZIF-8 is widely recognized as a representative material for searching high performance separation membranes because it has a pore size (about 3.4A) similar to the kinetic diameter of water molecules and is capable of achieving efficient molecular sieving. Xia Mengjiao by dispersing pre-synthesized ZIF-8 nanoparticles in a piperazine aqueous solution, followed by interfacial polymerization with trimesoyl chloride organic phase, ZIF-8 is encapsulated in the formed polyamide separation layer, aiming at improving membrane performance by molecular sieving using pore size of about 3.4 a. (Xia Mengjiao. Preparation of composite nanofiltration membranes based on ZIF-8 nanoparticle modification and their separation properties [ D ]. Zhejiang university, 2023.DOI:10.27464/D. Cnki gzsfu, 2023.002516.) In order to break through the performance limit of the traditional polyamide membrane, researchers try to prepare a mixed matrix membrane by taking a plurality of novel nano materials with regular pore channels and high specific surface areas as fillers. But all have the following fundamental drawbacks that have not been overcome. 1. The filler has poor interfacial compatibility with the matrix, and the MOF material and the COF material represented by ZIF-8 are both in rigid crystal structures, and the polyamide separation layer is a flexible organic polymer network. The two are significantly different in their physicochemical properties, resulting in very easy generation of non-selective nanovoids at the interface of the filler and the polymer matrix during the compounding process. These interface defects become preferential transport channels for ions under pressure, severely compromising the separation selectivity of the membrane, resulting in reduced salt rejection. 2. The long-term stability of the material system is insufficient, that is, MOF materials rely on coordination bonds between metal ions and organic ligands, and the chemical bonds have relatively low thermodynamic stability in an aqueous solution environment, particularly when residual chlorine exists or pH fluctuation is experienced during long-term operation, so that the MOF materials are easy to hydrolyze to cause the damage of a crystal structure and the performance attenuation. Although covalent bonds of COFs are more stable, their synthesis is often harsh and water stability of part of COFs remains a challenge, affecting the lifetime and reliability of the composite film. 3. The separation function is single and the preparation process is complex, the prior art mainly relies on the single aperture of the filler to carry out size screening, and the separation mechanism is not abundant. In addition, complex pretreatment (such as surface modification) and precise process control are required to realize uniform dispersion of the nano-filler in the film, and the nano-particles are easy to agglomerate, so that the preparation process is complex, the repeatability is poor, the cost is high, and the large-scale continuous production is not facilitated. Disclosure of Invention In view of the above, the technical problem to be solved by the invention is to provide a composite separation membrane, a preparation method and application thereof, and the composite separation membrane provided by the invention has better desalination rate and water flu