Effect of 2,2'-Bipyridine on the Adsorption of Zn(2+) Ions onto Silica Surface.
The influence of 2,2'-bipyridine (bipy) on adsorption of zink ions onto a highly dispersed silica surface has been studied. The enhanced adsorption of zink ions onto silica surface from the solution containing 2,2'-bipyridine is explained by ternary surface complex formation, { identical withSiOH(-m)Zn(bipy)(n)((2-m)+)}. The adsorbed Zn(2+) and bipy concentrations were measured at the adsorption from solutions with different ratios of Zn : bipy. The equilibrium reaction constants of binary and ternary complexes have been calculated using the constant capacitance model. The potentiometric titration data were used in order to determine the H(+)/Zn(2+) exchange stoichiometry. The composition of formed surface complexes has been confirmed with their UV absorption spectra. Copyright 2001 Academic Press.
Vlasova
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Institute of Surface Chemistry, National Academy of Sciences of Ukraine, pr. Nauki 31, Kiev, 03680, Ukraine