Surface complex formation at the adsorption of Cu2+ ions and 2,2'-bipyridine onto highly disperse silica

N. N. Vlasova; C. -W. Schlapfer; L. P. Golovkova; A. A. Svezhentsova; A. A. Chuiko

N. N. Vlasova Інститут хімії поверхні НАН України
C. -W. Schlapfer University of Fribourg
L. P. Golovkova Інститут хімії поверхні НАН України
A. A. Svezhentsova Інститут хімії поверхні НАН України
A. A. Chuiko Інститут хімії поверхні НАН України

Анотація

The enhanced adsorption of copper ions onto silica surface from the solution containing 2,2'-bipyridine is explained by ternary surface complex formation. The equilibrium reaction constants of binary and ternary complexes have been calculated using constant capacitance model. The potentiometric titration data were used in order to determine the H*/Cu²⁺ exchange stoichiometry. The adsorption of 2,2'-bipyridine on a copper-containing silica surface has been studied too. The equilibrium of 2,2'-bipyridine binding to immobilized copper ions are well reproduced by the constants for the formation of ternary surface complexes from an aqueous solution containing copper ions and 2,2'-bipyridine. This indicates clearly that under experimental conditions all reactions are reversible and speciation is controlled by the thermodynamics.

Посилання

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