Method for preparing polyvinyl alcohol nanofiltration membrane with high rejection coefficient

Abstract

The invention relates to a method for preparing a polyvinyl alcohol nanofiltration membrane with high rejection coefficient by using interface control. The method comprises the following steps: processing a polysulfone base membrane with 2%-8% glutaraldehyde aqueous solution for 2-4 minutes; drying the base membrane in a shade place; coating the polyvinyl alcohol aqueous solution with a mass fraction of 1%-5% onto the preprocessed membrane for 1-3 minutes; and processing the acquired compound membrane for 2-4 hours at 90 DEG C, so as to have full cross-linking reaction between the glutaraldehyde and the polyvinyl alcohol. The prepared polyvinyl alcohol nanofiltration membrane has a rejection coefficient of 98.5% to 2000ppm sodium sulfate, a rejection coefficient of 80.1% to 2000ppm sodium chloride and a rejection coefficient of 98.7% to 2000ppm polyethylene glycol 600. The method provided by the invention is novel and simple and the repeatability of membrane property test is good.

Description

A kind of preparation method of polyvinyl alcohol nanofiltration membrane with high rejection rate technical field The invention relates to a preparation method of a polymer material membrane, in particular to a preparation method of a nanofiltration membrane with good hydrophilicity and high rejection rate. Background technique Nanofiltration is a new type of membrane separation technology. The cut-off range of nanofiltration membrane is between 200-2000, the operating pressure is lower than that of reverse osmosis, and the rejection rate of monovalent ions is much lower than that of divalent ions. And it has a good separation effect on organic pollutants. The composite membrane is a membrane made by first using a polymer to make a porous support membrane, and then using another polymer to form an extremely thin and dense separation layer on the surface of the support membrane. Its preparation methods are divided into four categories including lamination method, dip coa...

AI Technical Summary

Problems solved by technology

The retention effect of the nanofiltration membrane prepared by direct coating with polyvinyl alcohol is not obvious, and it is easy to swell with water during use, and the polyvinyl alcohol that is swollen enough is easy to fall off the membrane surface, resulting in the scrapping of the membrane