Original scientific paper

Determination of the Ion Adso1·ption by the Radioactive Tracer Technique. VI. Counter Ion Adsorption on Silver Iodide in the Equivalency Region

D . Tesla-Tokmanovski ; lnstitute »Ruđer Boškovic« and Laboratory of Physi cal Chemistry Faculty of Science, University of Zagreb, Zagreb, Croatia, Yugoslavia
M. J. Herak ; lnstitute »Ruđer Boškovic« and Laboratory of Physi cal Chemistry Faculty of Science, University of Zagreb, Zagreb, Croatia, Yugoslavia
V. Pravdić ; lnstitute »Ruđer Boškovic« and Laboratory of Physi cal Chemistry Faculty of Science, University of Zagreb, Zagreb, Croatia, Yugoslavia
M. Mirnik ; lnstitute »Ruđer Boškovic« and Laboratory of Physi cal Chemistry Faculty of Science, University of Zagreb, Zagreb, Croatia, Yugoslavia

Abstract

Using radioactive t32Eu 3+ a nd 6oco2 + indicato11s the adsorption
of these ions on the surface of silver iodide precipitates was
measured. The experiments were performed in the equivalency
region, from pl 5.5 to pAg 5.5. The measurem e nts indicated a
constant amount of counter ions o f about 2 mgequiv .. /gmole of Ag!
adsorbed from pl 5.5 to pl 7. At higher pl a gradual d esorption
occurs, and at pAg 7.3 the zero point of adsorption i s attained. The
adsorbed amount is independe nt of the concentratio n of the counter
ion in the solution in the range from the coagulation concentration
up to ten times its value. By aging the precipitate or by some
other kind of pretreatm e nt the adsorbed amount of counter ions
is d ecreased. In addition the zero point of adsorption is shifted from
pAg 7.3 to pAg 7.1. Series of experments were performed to
establish the adsorption-desorption equil ib11ia of one ion in presence
of various concentrations of a second one.

Keywords

Hrčak ID:

208219

URI

https://hrcak.srce.hr/208219

Publication date:

15.7.1965.

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