Constructing a cationic porous organic polymer with [PF6]- charge-balanced anion for a rapid, selective and high-capacity thorium capture

Abstract

Thorium, recognized as a strategic resource, holds a significant position in the development and application of future energy sources. However, the currently available thorium is limited, and how to recover thorium from various thorium-containing mineral wastes as well as thorium-containing wastewater for recycling is an urgent problem for researchers. In this paper, we report a cationic porous organic polymer (namely ECUT-POP-34) for the rapid and selective adsorption of thorium from rare earth wastewater. The adsorption equilibrium can be fast finished within two minutes, exceeding almost all reported adsorbents for such use, while its saturated adsorption capacity reaches also as high as 588 mg/g, higher than most reported adsorbents for such use. Especially, in the presence of various rare-earth interfering ions in solution, ECUT-POP-34 also exhibits a high selective adsorption towards Th over these rare-earth ions. In addition, a good reusability is also observed. All these advantages suggest its superior application in recovery of thorium from thorium-containing wastewater. The Th-F coordination interaction derived from the charage-balanced anion of [PF₆]^- within the channel of material is viewed to contribute the fast, selective, and high-capacity thorium uptake.