Preparation of Chitosan-Alginate/PES Pervaporation Membranes for Bioethanol Dehydration

Abstract

In the last decade pervaporation membrane has become an antractive dehydration processs for azeotropic ethanol-water mixture. In this paper, chitosan-alginate/polyethersulfone (PES) composite membranes were prepared (by coating method) characterized as pervaporation membranes. The composite membranes were then examined to purify ethanol-water mixture. The characterization included degree of swelling both in water and ethanol, permeability measurement, surface morphology (by SEM) and surface chemistry (by FTIR). The results show that the increase in concentration of coating solution increases the degree of swelling in the water on the one hand, whereas the permeability and the degree of swelling in the ethanol decreases on the other hand. The highest permeability was obtained for the composite membrane prepared from a coating solution concentration of 1% with the ratio of chitosan to alginate was 0,33. The surface chemistry shows that the increase in concentration of chitosan - alginate solution increases the intensity of a specific wave number of C-O and C-N groups. Surface morphology indicates that the PES membrane surface is clearly covered by chitosan - alginate mixture. Performance examination demonstrates that the composite membrane prepared by 3% a coating solution (with the ratio of chitosan to alginate 3) can increase the bioethanol concentration from 95.5% to 99.6%.

Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2

“…CS has already been tested in pervaporation for dehydration of solvents, such as ethanol, isopropanol, tetrahydrofuran, and acetone, with high separation performance in terms of selectivity and water flux, as well as for gas separation [ 32 , 33 , 34 ]. Similar approaches for CS modification are used in pervaporation membrane development [ 35 , 36 , 37 , 38 , 39 ]. Likewise, attention has been given to materials based on CS copolymers with synthetic monomers [ 40 , 41 ], while they have not found a proper study for gas separation.…”