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

Efficient removal of radioactive Sr-90 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)[In-3(pydc)(6)]13.1H(2)O (SZ-6; pydc = 2,5-pyridinedicarboxylic acid) with the potential remediation ability towards radioactive Sr2+ from seawater. This material exhibits excellent beta and gamma 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 Sr-90 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.