Preparation method of nanofiltration membrane with high selectivity

Abstract

The invention provides a preparation method of a nanofiltration membrane with high selectivity. The method comprises the following specific steps: (1) preparing an aqueous phase solution (A phase): the aqueous phase solution contains polyfunctional polyamines, a proton absorber and polyvinylpyrrolidone, wherein the proton absorber is an organic base or inorganic base; (2) preparing an organic phase solution (B phase): the organic phase solution contains an organic solution of polyfunctional acyl chloride; (3) performing interfacial polymerization: an ultrafiltration base membrane is immersed in the aqueous phase solution (A phase) for 4-30 s, taken out, air-dried, immersed in the organic phase solution (B phase) for 10-60 s, taken out and subjected to heat treatment in a drying oven at 80-100 DEGC, and the product is obtained. According to the preparation method, polyvinylpyrrolidone is added to the aqueous phase formula for interfacial polymerization, so that the nanofiltration membrane with high selectivity is obtained with one step, industrial production is facilitated, and the obtained nanofiltration membrane has high selectivity and can take flux into account, thereby meetingpractical needs.

Description

technical field [0001] The invention relates to a preparation method of a nanofiltration membrane, in particular to a preparation method of a high-selectivity nanofiltration membrane. Background technique [0002] At present, the preparation of nanofiltration membranes mostly adopts the interfacial polymerization method. [0003] In order to obtain highly selective nanofiltration membranes, various methods have been developed at this stage. For example, in CN 103055726 B, a nanofiltration membrane is obtained by wet spinning, but it can only intercept dyes with relatively large molecular weights, and cannot be used for the separation of monovalent and divalent salts. [0004] The current relatively successful method is to perform interfacial polymerization on the base membrane to obtain a nanofiltration membrane. Such as CN107158981 A, after soaking the base film in ethanol or isopropanol solution for a long time, react with the solution of sodium nitrite and phenylenediam...

AI Technical Summary

Problems solved by technology

The nanofiltration membrane obtained by wet spinning cannot take into account the interception and flux of divalent salts, let alone the selectivity of monovalent and divalent salts

For the interfacial polymerization method, the current technology has complex operations, time-consuming (either pre-treatment or post-treatment), or cannot take into account the flux and the selectivity of monovalent and divalent salts.

Images