Tetraphenylimidodiphosphinate as solid phase extractant for preconcentrative separation of thorium from aqueous solution

A simple and reliable method for solid phase extraction of thorium using tetraphenylimidodiphosphinate is presented. The solid phase extraction process was optimized at equilibrium time 3 h, pH = 4.5, initial concentration 30 mg L-1 and extractant dosage 0.01 g with 98.95 % of removal efficiency and 29.68 mg g(-1) of adsorption capacity. The interfering ions experiments indicated that it had almost no effect on thorium adsorption. Kinetics data follow the pseudo-first-order model and equilibrium data agreed with the Langmuir isotherm model very well. FT-IR analysis indicated that imino group and phosphoryl acted as the significant roles in the solid phase extraction process.