Synthesis and characterization of a novel layered tin(IV) phosphate with ion exchange properties

Abstract

A novel layered tin(IV) phosphate, Sn(NH 4PO 4)(HPO 4)·2H 2O (δ-SnP–NH 4), was synthesized under mild hydrothermal conditions (190°C) in the presence of urea. The treatment of this compound with mineral acids gave a new phase of tin(IV) bis(monohydrogenphosphate), Sn(HPO 4) 2·3H 2O (δ-SnP–H). The layered nature of the solid was confirmed from amine intercalation, exfoliation in alkaline media, and the ion exchange behavior towards alkali and alkaline earth ions. High affinity (K d Cs ∼ 5 × 10 4 to 2 × 10 5 mL g −1) and capacity (160–200 mg Cs + per g of exchanger) for Cs + makes these materials promising for selective radioactive cesium removal from contaminated groundwater and nuclear waste.