Ion‐exchange Properties of γ‐Zirconium Phosphate.

γ‐Zirconium phosphate (γ‐ZrP) has potential as a very useful inorganic ion‐exchanger due to its stability under thermal and acidic conditions. We recently reported its facile synthesis using a modified solventless method, which could make the exploitation of its ion‐exchange properties for cleanup of radioactive materials and extraction of valuable ions feasible. The adsorption isotherms of Rb+ and Sr2+ over γ‐ZrP are described well with the Langmuir model, with maximum adsorption capacity of 1.52 and 1.31 mmol/g, respectively. Both ions adsorb on γ‐ZrP following pseudo‐second order kinetics with a much faster uptake of Rb+ than of Sr2+. γ‐Zirconium phosphate shows very high affinity for Rb+, allowing its enrichment from low‐concentration solutions. Notably, Rb+ is selectively removed from complex solutions containing large amounts of Na+, Mg2+, Ca2+, or transition metals such as Cu2+, Ni2+, Fe2+, Fe3+, Co2+ and Zn2+. The used sorbent can be fully regenerated by nitric acid, enabling the recovery of Rb+. [ABSTRACT FROM AUTHOR]