Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5413328 | Journal of Molecular Liquids | 2008 | 7 Pages |
Abstract
The hydrolysis of VO2+ and the complex with sulfate were studied potentiometrically, spectrophotometrically and calorimetrically, in NaCl aqueous solution (0 < I â¤Â 1 mol Lâ 1) and at t = 25 °C. The formation of two hydrolytic species VO(OH)+ and VO2(OH)22+ and one complex with sulfate was found, with log β = â 5.65 for the reaction VO2+ + H2O = VO(OH)+ + H+, log β = â 7.02 for the reaction 2VO2+ + 2H2O = (VO)2(OH)22+ + 2H+ and log K = 1.73 for VOSO40 species (at I = 0.1 mol Lâ 1 and t = 25 °C). For these species, using calorimetric data, ÎH and TÎS values were also obtained. By using the above values, interactions of VO2+ with acetate (ac), malonate (mal), succinate (suc), 1,2,3-propanetricarboxylate (tca) and 1,2,3,4-butanetetracarboxylate (btc) ligands were studied potentiometrically and spectrophotometrically. The formation of ML+, ML20 and MLOH0 for ac; ML0, MLH+, ML22â and ML2Hâ for mal; ML0, MLH+ and MLOHâ for suc; MLâ and MLH0 for tca and ML2â, MLHâ and MLH20 for btc were found. Formation constants are reported at I = 0.1 mol Lâ 1, together with SIT parameters for the dependence on ionic strength. By visible spectrophotometric measurements, λmax and εmax values for the relevant species in solution were determined.
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Authors
Silvia Berto, Pier G. Daniele, Claudia Foti, Enrico Prenesti, Silvio Sammartano,