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An approach to the development of cellulose acetate ultrafiltration membranes
Author(s) -
Kunst B.,
Sourirajan S.
Publication year - 1974
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1974.070181121
Subject(s) - membrane , casting , aqueous solution , solvent , cellulose acetate , ultrafiltration (renal) , evaporation , acetone , chemical engineering , materials science , chemistry , polymer , perchlorate , cellulose , chromatography , organic chemistry , metallurgy , ion , thermodynamics , biochemistry , physics , engineering
The film‐casting solution consisted of a mixture of cellulose acetate, acetone, and aqueous magnesium perchlorate [Mg(ClO 4 ) 2 :H 2 O = 1:8.5], designated as polymer P, solvent S, and nonsolvent N, respectively. Using the composition P:S:N = 17: 69.2: 13.8 as reference, films were obtained from 19 different casting solutions in which the weight ratios S/P, N/S, and N/P were varied in different directions. The casting solution temperature was 0°C, and solvent evaporation period during film formation was minimum in most cases. The effects of variations of casting solution temperature and solvent evaporation period were also briefly studied. Reverse osmosis experiments with resulting membranes were carried out at 100 psig using 200 ppm NaCl–H 2 O as the feed solution. Decrease in S/P, increase in N/S, and increase in N/P in the casting solution, decrease in temperature of the casting solution, and increase in solvent evaporation period tend to increase the size of pores on the surface of resulting membranes in the ascast condition. Increase in S/P in the casting solution, and increase in the temperature of the casting solution tend to increase the effective number of pores on the membrane surface. These results offer definitive physicochemical criteria in terms on solution structure–evaporation rate concept for developing useful cellulose acetate ultrafiltration membranes.