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Adsorption of hexavalent chromium on cationic starches with different degree of crosslinking
Author(s) -
Sidlauskiene D.,
Klimaviciute R.,
Zemaitaitis A.
Publication year - 2007
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.27461
Subject(s) - adsorption , cationic polymerization , hexavalent chromium , exothermic reaction , chromium , chemistry , thermodynamics , chemical engineering , entropy (arrow of time) , materials science , polymer chemistry , organic chemistry , physics , engineering
The influence of the degree of crosslinking in the association with the degree of cationization on the adsorption of Cr(VI) by crosslinked cationic starches (CCS) was examined. The amount of adsorbed Cr(VI) depends on the preparation of CCS before adsorption experiments (dry or preswollen CCS) and has a higher value when dry CCS are used. The amount of crosslinks in CCS needed to reach the maximum effectiveness of the cationic groups of CCS in the binding of Cr(VI) depends also on the form in which CCS are used. The adsorption capacity for Cr(VI) decreases both with dry and preswollen CCS when the adsorption temperature increases. The thermodynamic parameters are calculated. The negative values of Δ G ° and Δ H ° indicated that the adsorption process in both cases was spontaneous and exothermic. If preswollen CCS is used, the entropy change has a positive value and indicates that the randomness of the system increases, whereas the negative value of entropy change when Cr(VI) species are adsorbed by dry CCS shows that in this case the order of the system increases like in the classical adsorption process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008