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Interaction of microcrystalline chitosan (MCCh) with Mo(VI) in aqueous solution
Author(s) -
Kufelnicki Aleksander,
Lichawska Marta E.,
Bodek Kazimiera H.
Publication year - 2009
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.30756
Subject(s) - potentiometric titration , chitosan , aqueous solution , molybdenum , microcrystalline , ligand (biochemistry) , chemistry , stability constants of complexes , metal , hydrolysis , proton , nuclear chemistry , crystallography , analytical chemistry (journal) , inorganic chemistry , organic chemistry , physics , biochemistry , receptor , electrode , quantum mechanics
The molybdenum(VI) complex formation equilibria of microcrystalline chitosan (MCCh) with three different degrees of deacetylation (DD = 0.750, 0.812, and 0.948) were studied by pH‐potentiometric and UV‐spectrophotometric methods. The hydrolysis constants of Mo(VI) were evaluated under exactly the same conditions as during the experiments in presence of chitosan. It has been shown that the complexation model depends on DD. Besides the formation of a ligand to metal 2 : 1 MoO 2 B 2 2+ complex (“bridge model”) with A = MoO 4 2− , B = MCCh, H = proton, the 1 : 1 MoO 3 B species (“pendant model”) has been confirmed as well for the two lower values of DD and moderate excess of ligand. At the highest DD, the results indicate only the occurrence of 2 : 1 species. When taking into account the number of protons in reaction as the third index, the corresponding average overall stability constants log β abh of MoO 3 B and MoO 2 B 2 2+ reach log β 112 = 13.8 and log β 124 = 27.9, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009