On the mechanism of ion exchange in zirconium phosphates—XXII mixed zirconium titanium phosphates
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α-Titanium phosphate, Ti(HPO4)2·H2O, was found to form two sodium ion exchanged phases. A half exchanged phase of ideal composition TiNaH(PO4)2·4H2O formed first. However, before all of the titanium phosphate was converted to this phase a second phase of higher Na+ content formed. Thus, a three phase solid existed until sufficient sodium ion uptake (∼ 5.5 meq/g) produced only the two exchanged phases. Finally, the half exchanged phase was converted to the more highly loaded one and this latter phase existed from 6-8 meq/g of Na+ uptake. Severe disordering of the crystal lattice during exchange is proposed to explain this unusual exchange behavior. A broad range of titanium phosphate-zirconium phosphate solid solutions was found to form. Their behavior towards Na+H+ exchange was determined and interpreted on the basis of the known behavior of the pure phases. Mixed TiZr solid solutions of their pyrophosphates were obtained at elevated temperatures. © 1978.
author list (cited authors)
Clearfield, A., & Frianeza, T. N.