Solvent extraction of thorium(Ⅳ) using W/O microemulsion

摘要

The extraction of thorium(IV) was investigated using two types of W/O microemulsion,one of which was formed by a surface-active saponified extractant sodium bis(2-ethylhexyl) phosphate(NaDEHP) and the other was formed by a mixture of an anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate(AOT) and an extractant bis(2-ethylhexyl)phosphoric acid(HDEHP) as the cosurfactant.The extraction capacities of the above two systems were higher than that of the HDEHP extraction system.High concentration of NaNO 3 showed no influence on the extraction in the NaDEHP based W/O microemulsion system,whilst reduced the extractability in the AOT-HDEHP W/O microemulsion system.The mechanism in acidic condition was demonstrated by the log-log plot method.The structure of the aggregations and the water content in the organic phase after extraction were measured by dynamic light scattering and Karl Fischer water titration,respectively.It was found that NaDEHP based W/O microemulsion broke up after extraction,while AOT-HDEHP W/O microemulsion was reserved.