On the mechanism of ion exchange in zirconium phosphates—XXVII: Dehydration behavior of Cu(II) ion exchanged phases

Abstract

The dehydration behavior and phase changes of crystalline α-zirconium phosphate exchanged to increasing levels of Cu(II) content have been determined by thermal and X-ray methods. The fully exchanged compound is ZrCu(PO 4) 2·4H 2O which loses 1 mole of water below 100°C and this phase in turn loses another 1.5 moles below 200°C forming ZrCu(PO 4) 2·1.5H 2O. Additional mole of water is lost between 200 and 300°C yielding a solid with a poorly defined X-ray pattern. However, annealing in this temperature range produces a well crystallized phase (termed phase G). This phase has a variable water content ranging from 0.5 to zero moles and long heating times at 400–450°C are required to achieve the anhydrous state. In the region of low copper contents the phases formed are solid solutions which resemble α-zirconium phosphate phases.