Speciation observed by cation exchange

The mediation of uptake of radioisotopes of Co, Ni & Zn by the presence of differing anion concentrations has been examined in the range 10−2 → 10−5M with respect to metal ion concentration. The cation exchange substrates chosen were a range of zeolite (aluminosilicate) exchangers. Selection was based upon their regular structures, variation in Si/Al isomorphous replacement and microporosity. Very clear effects were observed whereby changes in cation uptake can be explained by the phenomenon of cation speciation. Observation of cation exchange capacity changes affords a method of ‘sensing’ speciation.