Sorption of trace concentrations of gallium(III) and iodide ions on tin(II) hydroxide

Abstract

The results of sorption measurements for gallium (III) and iodide ion traces onto tin(II) hydroxide from aqueous heterogeneous systems are given. Since only tagged sorbate was used (67Ga and 1311), in the determination of sorption by radioactive tracer method, it was necessary to establish the pH interval of tin(II) hydroxide in/stability. This was done by a turbidimetric method and the pH region of instability between 3 and 9 was found. The sorption results indicate a difference in sorption ability of gallium(III) and iodide as it appears from the dependence of the amount sorbed on contact time between heterogeneous reactants (sorbentsorbate). The amounts sorbed increase with increasing contact times at higher pH values for Ga(III) but remain unaffected for iodide sorption. Thus the sorption of iodide ions seems to be restricted to the solid surface while the sorption results for gallium(III) indicate the diffusion of sorbate into sorbent as a possible parallel mechanism. Those processes could be taken as compatible with the porous-double-layer mechanism which has been proposed in literature for aqueous heterogeneous oxide systems.