Synthesis of Tributyl Phosphate-Coated Hydroxyapatite for Selective Uranium Removal

Efficient and rapid removal of radioactive contaminants is crucial when they are released into the environment following nuclear accidents. Here, different types of apatite were synthesized using tributyl phosphate (TBP) and tested for the removal of uranium from various solutions using different reaction times and uranium concentrations. The uranium adsorption results showed that uranium adsorption reached a steady state within 24 h in tests open to atmosphere at a slightly alkaline pH in different background solutions. TBP-coated hydroxyapatite removed U better than hydroxyapatite alone did. The U removal mechanism was considered as multilayer adsorption, showing the best fit to the Freundlich isotherm. The maximal U adsorption capacity determined from the Langmuir isotherm is 38 mg of U g–1. Because of the high U removal efficiency, even at the high pH used in this study, TBP-coated hydroxyapatite appears to be a promising adsorbent for the removal of U from various waste streams as well as for recovery of U from seawater.