The Ion Exchange Properties of Monoclinic Zirconia: A Study with Ion Selective Electrodes

The amphoteric ion exchange and sorptive properties of monoclinic zirconia are studied here in detail. Microcrystals of zirconia have been prepared and systematically charaterized to give a full understanding of the method for crystal growth. A novel algorithm for calculation of ion exchange capacity employing a single pH electrode is utilized. Results are obtained which support the Donnan model for the exchange process. Anion and cation exchange capacities are shown to be a single valued function of the acid pA or base pB. Reversibility is demonstrated and enchancement of exchange capacity is accomplished through common ion addition. A titration system is developed which incorporates additional ion selective electrodes and includes computer programs for calibration, ion exchange capacity calculations and graphic display of results. This system confirms previous work by showing chloride uptake to match proton uptake. Fluoride uptake by monoclinic crystals of zirconia is revealed to be ten times higher than typical capacities for exchangers of this kind. Again uptake is demonstrated to be reversible, and a single valued function of the acid pHF. Exchange properties of zirconia for fluoride ion are expained by ligand exchange and incorporation in the framework of the oxide