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Evapomeation characteristics of cross‐linked quaternized chitosan membranes for the separation of an ethanol/water azeotrope
Author(s) -
Uragami Tadashi,
Takuno Makoto,
Miyata Takashi
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(200206)203:9<1162::aid-macp1162>3.0.co;2-q
Subject(s) - azeotrope , membrane , permeation , chemistry , pervaporation , chitosan , polymer chemistry , chemical engineering , ethanol , chromatography , organic chemistry , biochemistry , distillation , engineering
The permeation and separation characteristics during evapomeation of an ethanol/water azeotrope (96.5 wt.‐% ethanol) through quaternized chitosan (q‐Chito) membranes and cross‐linked q‐Chito membranes, which were cross‐linked with diethylene glycol diglycidyl ether (DEDGE), were studied. Both the q‐Chito and the cross‐linked q‐Chito membranes showed high water‐permselectivity for an ethanol/water azeotrope. The permeation rates for both membranes decreased and the water‐permselectivities increased, with an increasing degree of quaternization of the chitosan and cross‐linker concentration. The mechanism of separation for the ethanol/water azeotrope through the q‐Chito and cross‐linked q‐Chito membranes was analyzed by the solution‐diffusion model. Increasing permeation temperature increased the permeation rate and decreased the water‐permselectivity for both membranes. However, the permeation rates of a cross‐linked q‐Chito membrane at 60–80°C were almost the same as those of the q‐Chito membrane, and the separation factors for water‐permselectivity (α sep.H 2 O/EtOH =4 100–4 200) in the former were greater by two orders of magnitude as compared to the latter (α sep.H 2 O/EtOH = 47–58). The above results were discussed from the viewpoints of the physical and chemical structure of the q‐Chito and cross‐linked q‐Chito membranes.Effects of the degree of quaternization on the separation factor (□), the sorption selectivity (○), and the diffusion selectivity (•) for an ethanol/water azeotrope using the q‐Chito membranes.