(A) study on water-repelling catalyst for the separation of low-concentration hydrogen isotopes

Abstract

Nuclear energy generated by nuclear powerplant is nowadays regarded as an indispensable energy source in the pursuit of carbon neutrality. To ensure the safe operation, it is imperative to manage the waste containing low-concentration tritium(T). Recently, the separation of T is achieved through the Combined Electrolysis and Catalytic Exchange (CECE) process which involves the exchange reaction of T between hydrogen and water, transpiring within Liquid-phase catalytic exchange (LPCE). While such a process, the regulation of the hydrophobicity of the catalyst is challenging because water acts as a reactant but also serves as a poison, deactivating the catalyst. This study proposes the catalyst in the form of a composite with post-synthetically modified metal-organic framework (MOF) loaded with platinum and macroporous polymer. This catalyst prevents deactivation caused by excessive water access by leveraging its water-repelling property, all the while allowing the entry of a sufficient number of water molecules for the reaction. Its structural characteristics, water-repelling properties were analyzed. The influence of the hydrophobically modified MOF support introduced in the catalyst was confirmed by measuring column efficiency under various conditions and proving the dynamic adsorption of water molecules on the platinum. Furthermore, through the radiation stability assessment and revealing the maintenance of catalytic activity for long-term reaction, we demonstrated the suitability of the proposed catalyst for hydrogen-water isotope exchange reaction.