Metal Ammonium Phosphates Ion Exchangers for the Remediation of Low-Level Nuclear Wastes

Abstract

The nuclear industry generates large volumes of liquid wastes during decommissioning and decontamination activities which require extensive clean-up for recycle and/or disposal. The disposal of spent ion exchange materials used to clean these decontamination liquors is challenging and costly for the nuclear industry due to problematic end-of-life handling and low capacities of these materials for most radionuclides. Certain mixed-metal phosphates could be advantageous in this role due to their inherent vitrification properties and potentially high capacities for cationic and/or anionic radionuclides. Similar ammonium-based ion exchangers like the caesium-selective ammonium phosphomolybdate (AMP) are well known in the nuclear industry, but outside of this, such materials remain largely unexplored for this purpose. In this publication, we assess several metal ammonium phosphates (MAPs) and related compounds prepared using a continuous flow technique for their ability to act as ion exchangers for the remediation of surrogate radionuclides from a model decontamination solution, and discuss their possible implementation for the cleanup of low-level nuclear wastes.