Ion-Exchange Extraction of Zn2+, Co2+, and Ni2+ Cations from Solutions by Titanium Phosphate Matrices.

The experimental data reported in this paper suggest that titanium(IV) oxyhydroxyphosphate-based ion-exchange materials are potentially attractive for extraction of heavy metal cations from solutions. We have studied the time-dependent ion exchange activity of titanium phosphates for Zn2+, Co2+, and Ni2+ cations in relation to the liquid : solid ratio, temperature, and equilibrium pH of the cation exchange process. The results demonstrate that the selectivity of an ion exchanger for metal cations is determined by the ionic radii of the metals. Conditions for effective use of titanium phosphate materials for extraction of Zn2+, Co2+, and Ni2+ cations from solutions (liquid : solid ratio, temperature, and pH) have been optimized experimentally. [ABSTRACT FROM AUTHOR]