Preparation method of high-selectivity reverse osmosis membrane by covering membrane surface defects

Abstract

The invention discloses a preparation method of a high-selectivity reverse osmosis membrane by covering membrane surface defects. The high-selectivity reverse osmosis membrane is compounded by polymerizing a polyamide membrane layer on the upper interface of a polysulfone ultrafiltration membrane. In the preparation process of the high-selectivity reverse osmosis membrane, the concentration of an amine monomer in an aqueous solution is regulated and controlled to be 2.0-5.0 wt%, the concentration of an acyl chloride monomer in an oil-phase solution is regulated and controlled to be 0.12-0.25 wt%, and the mass concentration of the acyl chloride monomer in the oil-phase solution is controlled to be 1 / 20 to 1 / 10 of the mass concentration of the amine monomer in the aqueous solution. According to the preparation method of the high-selectivity reverse osmosis membrane, generation of defects on the surface of the membrane and formation of a secondary structure can be effectively inhibited, and the selectivity of the membrane can be greatly improved while it is guaranteed that the permeability of the membrane is not lost.

Description

technical field [0001] The invention relates to a preparation method of a high-selectivity reverse osmosis membrane by covering the surface defects of the membrane. Background technique [0002] Although most of the earth is water, it is basically seawater, and seawater is rich in high concentrations of inorganic salts, heavy metal elements, etc., so seawater cannot be directly used by humans. In the middle of the 20th century, the United States set up a special brine office to try to use reverse osmosis membrane technology to desalinate seawater to solve the problem of extreme drought. [0003] At that time, the membrane material was mainly cellulose acetate, and the membrane had a highly symmetrical structure on both sides, which increased the membrane thickness to a certain extent, resulting in low permeability; subsequently, Indian scientist Srinivasa Sourirajan and the United States Scientist Sidney Loeb developed an asymmetric cellulose acetate membrane, which greatly...

AI Technical Summary

Problems solved by technology

[0005] In view of the technical problems existing in the prior art, that is, the source of defects on the surface of polyamide membranes is not clear, and so far there is no research report on how to avoid the generation of defects based on the regulation of the reaction monomer concentration. Less attention has been paid to the secondary structure of the layer, and the degree of cross-linking and compactness of the secondary structure film layer are worthy of further investigation

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