Synthesis and Characterization of the Layered Zirconium Arsenate Zr2O3(HAsO4)·nH2O

Layered sodium zirconium arsenate of composition Zr2O3(NaAsO4)·3H2O was prepared by the reaction between Zr(OC3H7)4 and sodium arsenate in alkaline media (pH > 12) under mild hydrothermal conditions (180–200°C). Two hydrogen forms of the zirconium arsenate (ψ-ZrAs) Zr2O3(HAsO4)·3H2O and Zr2O3(HAsO4)·H2O, were prepared by acid treatment of the sodium form. The intercalation of n-alkylamines into the ψ-ZrAs from the gas phase was studied. The synthesized materials were characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy and powder X-ray diffraction. The data indicate that the zirconium arsenate is isostructural to ψ-Zr2O3(HPO4)·nH2O (n = 0.5, 1.5). The new compounds exhibit high hydrolytic stability in alkaline media. The ion exchange behavior of the ψ-Zr2O3(HAsO4)·3H2O towards alkali, alkaline-earth, and some di- and tri-valent metal cations in different solutions was studied over a wide pH range (2–14) by the batch technique.