Method for preparing polypyrrole monovalent selective cation exchange membrane in situ

Abstract

The invention discloses a method for preparing a polypyrrole monovalent selective cation exchange membrane in situ. The method comprises the following steps: (1) after an ordinary cation exchange membrane to be modified (white, 50 cm<2>) is immersed into a hydrochloric acid solution with the concentration of 0.2 mol / L for a period of time, washing an excess acid on the surface by using deionized water; (2) immersing the hydrogen-typed cation exchange membrane into a 2-5wt% pyrrole ethanol solution (200 mL) for 1 min; taking out the membrane, placing the membrane horizontally for more than 2 min; and after ethanol on the surface is completely evaporated, immersing the membrane into an oxidant solution with a certain concentration (such as ferric chloride, ammonium persulfate and hydrogen peroxide, 200 mL) for a period of time, wherein the membrane is black at the moment, and the result proves that the membrane is supported with polypyrrole; and (3) repeating the step (2) for a pluralityof times so as to obtain the polypyrrole selective cation exchange membrane with a plurality of layers. According to the method provided by the invention, the polymerization method of pyrrole is simple and effective, and the modified membrane has uniformly-deposited surface matter and significantly-improved monovalent ion selectivity.

Description

technical field

[0001] The invention belongs to the field of ion exchange membranes, and particularly relates to a method for preparing polypyrrole monovalent selective cation exchange membranes in situ. Background technique

[0002] With the development of science and technology, membrane separation technology has attracted more and more attention. As an important component in the field of membrane separation technology, ion exchange membrane technology has the advantages of strong selectivity, high separation efficiency, and low energy consumption. play an increasingly important role. However, ion exchange membrane technology still has certain defects in practical applications, such as the separation of homopolar monovalent ions and multivalent ions, low ion transport capacity, and low current efficiency. Especially during the electrodialysis process, the scaling of divalent metal ions on the surface of the water dissociation membrane caused by ion migration will lead to...

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