US 12,263,444 B2
Solvent-resistant polymeric nanofiltration membrane, preparation method and use thereof
Jian Jin, Suzhou (CN); and Zhenggong Wang, Suzhou (CN)
Assigned to SOOCHOW UNIVERSITY, Suzhou (CN)
Appl. No. 17/794,224
Filed by SOOCHOW UNIVERSITY, Suzhou (CN)
PCT Filed Sep. 22, 2020, PCT No. PCT/CN2020/116667
§ 371(c)(1), (2) Date Jul. 20, 2022,
PCT Pub. No. WO2021/227330, PCT Pub. Date Nov. 18, 2021.
Claims priority of application No. 202010392887.9 (CN), filed on May 11, 2020.
Prior Publication US 2023/0100275 A1, Mar. 30, 2023
Int. Cl. B01D 69/02 (2006.01); B01D 61/02 (2006.01); B01D 67/00 (2006.01); B01D 71/64 (2006.01)
CPC B01D 61/027 (2013.01) [B01D 67/0006 (2013.01); B01D 69/02 (2013.01); B01D 71/64 (2013.01); B01D 2323/2181 (2022.08); B01D 2325/30 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for preparing a solvent-resistant polymeric nanofiltration membrane, comprising steps of:
(1) reacting a diamine monomer with a dianhydride monomer in the presence of a catalyst in a first polar organic solvent at 160-230° C., to form a polyimide;
wherein the diamine monomer comprises at least one diamine monomer with a carboxyl group and at least one diamine monomer without a carboxyl group; the structural formula of the polyimide comprises a first repeating unit and a second repeating unit, the first repeating unit comprising at least one polymeric segment of the dianhydride monomer and the diamine monomer with a carboxyl group, the second repeating unit comprising at least one polymeric segment of the dianhydride monomer and the diamine monomer without a carboxyl group; and
wherein the boiling point of the first polar organic solvent is higher than 160° C.;
(2) dissolving the polyimide in a second polar organic solvent, to form a membrane-forming solution with a concentration of 10 wt % to 40 wt %; then, performing phase inversion after the membrane-forming solution is formed into a membrane, to obtain an intermediate membrane;
(3) treating the intermediate membrane with an organic solution of a metal salt, so that the metal ion is coordinated and cross-linked with the carboxyl group in the polyimide, to obtain the solvent-resistant polymeric nanofiltration membrane after the cross-linking is completed, wherein the metal salt is selected from divalent and/or multi-valent metal salts.