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Preparations and properties of sodium alginate formed‐in‐place membranes
Author(s) -
Wang Xingwu,
spencer H. Garth
Publication year - 1996
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/(sici)1097-4628(19960801)61:5<827::aid-app15>3.0.co;2-u
Subject(s) - membrane , microfiltration , bovine serum albumin , chromatography , chemistry , chemical engineering , polyelectrolyte , sodium , permeability (electromagnetism) , substrate (aquarium) , ionic strength , polymer , aqueous solution , organic chemistry , biochemistry , oceanography , engineering , geology
Sodium alginate formed‐in‐place membranes were formed on a macroporous titanium dioxide membrane substrate at pH 3.3, 6.5, and 10.5. To investigate the rate and the mechanism of the membrane formation, the dependence of the pressure‐to‐flux ratio, P / J , on time, t , during the formation was evaluated using diagnostic graphs; ( P / J ) 2 , ( P / J ) 1/2 and —In( P / J ) vs. t . The microfiltration properties of the membranes were investigated by determining the permeability, J / P , and the rejection of a protein, bovine serum albumin (BSA). in 1 g/L solutions as a function of the concentration of added KCl. The stability of the membranes was evaluated by comparing the ratio of the resistances of the membranes at the end of the formation, R , after crossflow rinsing, R m , and after crossflow rinsing following the BSA microfiltration experiment, R a . The linearity of the graphs of ( P / J ) 2 vs. t of the membranes formed in neutral or basic conditions indicated that the membranes were formed by deposition of a layer, or cake, of the polyelectrolyte on the substrate, while the membrane formed at lower pH was initially deposited as a layer followed by a more complex mechanism. Only the membranes formed pH 3.3 were stable to the crossflow water rinse and retained high BSA rejection at high ionic strength. Their permeabilities were about 50% lower than the permeabilities obtained with the membranes formed at higher pH. The BSA rejection results imply that a continuous sodium alginate membrane is present for the membranes formed at pH 3.3 and that membranes retaining a macroporous structure are present for the membranes formed at pH 6.5 and 10.5. © 1996 John Wiley & Sons, Inc.