Highly efficient extraction of thorium from aqueous solution by 2-carboxyethylphosphonic acid-functionalized chitosan xerogel

Efficient separation and enrichment of thorium from aqueous solutions is an important subject in the field of energy and ecological environment. In this study, a novel polymer-based xerogel was prepared by a crosslinking reaction of 2-carboxyethyl phosphonic acid functionalized chitosan(CCS-TCEP) and was applied to the adsorption of Th(IV) ions. The maximum adsorption capacity of CCS-TCEP could reach 311.6 mg/g with an excellent selectivity due to the abundant binding sites for thorium provided by TCEP. Moreover, this material has a high adsorption rate and the adsorption equilibrium could be reached within 60 min. After 5 cycles of reuse, the adsorption capacity of CCS-TCEP still retained more than 80 % of its initial value. Furthermore, the extraction mechanism of CCS-TCEP for Th(IV) ions was also analyzed in detail by FT-IR, XPS and DFT calculation. This study indicates that CCS-TCEP can be used as a potential adsorbent for efficient extraction of thorium from aqueous waste.