Remarkably enhanced direct dissolution of plutonium oxide in task-specific ionic liquid: insights from electrochemical and theoretical investigations

Abstract

A simple way of catching a big fat element: plutonium from radioactive waste by a task specific ionic liquid.

Synthesis and Dissolution of Metal Oxides in Ionic Liquids and Deep Eutectic Solvents

“…It underlines the correlation between the lattice energy of a metal oxide and its solubility [125]. However, our findings show that this assumption is not valid for all metal oxides, which is in agreement with the report by Gupta, Chandrakumar et al who dissolved PuO 2 [18], despite predicted insoluble by Qin et al [125]. Apparently, the lattice energy is not the only factor influencing the solubility, but also other parameters, such as reaction conditions [18] and crystal phase are important.…”

“…However, our findings show that this assumption is not valid for all metal oxides, which is in agreement with the report by Gupta, Chandrakumar et al who dissolved PuO 2 [18], despite predicted insoluble by Qin et al [125]. Apparently, the lattice energy is not the only factor influencing the solubility, but also other parameters, such as reaction conditions [18] and crystal phase are important. As the dissolution of metal oxides in [Hbet][NTf 2 ] comes down to an acid-base reaction, we consider especially the basicity of the metal oxide to be significant.…”

“…Although numerous crystal structures of polymeric metalbetaine-aqua complexes were described [102,103], synchrotron techniques revealed a dissociation to the monomeric complexes in solution [114]. A large number of oxides of main and subgroup as well as lanthanide and actinide metals were dissolved in aqueous [Hbet][NTf2] [18,102,103,113,114,117,124,125], however, negligible dissolution was observed for not readily soluble, more covalent metal oxides, such as Al2O3 [102,126,127], Fe2O3 (haematite) [126,127], MnO2 [102], TiO2 (anatase-rutile) [127], cobalt oxides [102] and U3O8 [117]. Gupta, Chandrakumar et al showed that the addition of water as a solvent is not necessary in As an example for carboxyl-functionalised ILs, a lot of research has been performed using the IL [Hbet][NTf 2 ], first described by Binnemans et al [102].…”

“…Gupta, Chandrakumar et al showed that the addition of water as a solvent is not necessary in order to obtain metal-betaine-water complexes, but the water evolving during the reaction is sufficient when refluxed [18].…”

“…Furthermore, hydrometallurgical methods are applied [16], however, this often is accompanied by the simultaneous dissolution of undesired materials [17]. In addition, metal oxides are present in nuclear waste, where large amounts of secondary waste are generated in the course of metal extraction [18].…”