An Integrated Strategy for Pre-Disposal of Spent Cation-Exchange Resins by Repurposing Industrial By-Products

Large amounts of spent, radioactive, ion-exchange resins have been generated worldwide, and their production is expected to grow due to a renaissance of nuclear power. Such waste is being stored at individual plant sites around the world, awaiting a reliable disposal route to overcome the downsides of the state-of-the-art management approaches. In this work, a first-of-its-kind pre-disposal strategy is proposed, based on the integration of a heterogeneous Fenton-like treatment with conditioning in an alkali-activated matrix. In particular, the circular economy is pursued by repurposing two industrial by-products, coal fly ash and steel slag, both as catalysts of the Fenton treatment and precursors of the conditioning matrix. The obtained waste forms have been preliminarily tested for leaching and compressive strength according to the Italian waste acceptance criteria for disposal. The proposed technology, tested at laboratory scale up to 100 g of virgin cationic resin, has proven successful in decomposing the waste and synthesizing waste forms with an overall volume increase of only 30%, thereby achieving a remarkable result compared to state-of-the-art technologies.