A hydrolytically stable anionic layered indium–organic framework for the efficient removal of 90Sr from seawater

Abstract

Efficient removal of radioactive ⁹⁰Sr from nuclear waste solutions and natural water systems is of vital importance due to its radioactive nature and high mobility. We present here an anionic layered compound (NC₄H₁₂)(NC₂H₈)₂[In₃(pydc)₆]·13.1H₂O (SZ-6; pydc = 2,5-pyridinedicarboxylic acid) with the potential remediation ability towards radioactive Sr²⁺ from seawater. This material exhibits excellent β and γ radiation resistance both in air and in aqueous solutions. Besides, this material could maintain its structural integrity in real seawater for 77 days. The adsorption experiment results show that SZ-6 exhibits superior Sr²⁺ removal capability over a wide pH range from 4 to 12 with fast adsorption kinetics and high selectivity. The effective removal of ⁹⁰Sr from real seawater was demonstrated as well. Our results strongly suggest the potential application of SZ-6 for selectively capturing radionuclides in natural water systems.