Selective separation of water from water–ethanol solution through quarternized poly(4‐vinylpyridine‐co‐acrylonitrile) membranes by pervaporation technique

Abstract

Abstract Polymer membranes having cationic charge site, poly(1‐alkyl‐4‐vinylpyridinium iodide‐co‐acrylonitrile) (alkyl: methyl, butyl, or octyl) were prepared in terms of coulombic interaction for separation of water–ethanol mixtures. The incorporation of cationic charge site into the membrane led to improve not only separation factors (selectivity toward water) but also flux number in the separation of aqueous ethanol solution by pervaporation technique. Target values, which were requested to have from the viewpoint of industrial utilization for separation of aqueous ethanol solution were attained as follows: separation factor toward water over 50 and flux value over 500 g m −2 h −1 , through poly(1‐methyl‐4‐vinylpyridinium iodide‐co‐acrylonitrile) (membrane 3 ) (quarternized fraction of pyridinium moiety, 89.5%; mol fraction of pyridinium moiety, 0.034) and poly(1‐butyl‐4‐vinylpyridinium iodide‐co‐acrylonitrile) (membrane 5 ) (quarternized fraction, 100%; mol fraction of pyridinium moiety, 0.038). It was found that the introduction of cationic charge site into the membrane was one of feasible methods to obtain suitable membranes for water permselective membranes in the separation of water–ethanol mixtures.