Adsorption performance of talc for uranium removal from aqueous solution

Adsorption of uranyl ions onto talc from aqueous solutions was investigated in batch adsorption experiments. The study has been conducted to investigate the effects of the pH of solution, contact time, initial concentration and presence of other metals that could compete with uranium for adsorption sites. The kinetic sorption data were found to fit the first-order kinetic model. The experimental isotherm data of uranium sorption were examined using the Freundlich, the Langmuir and the BET models. The results obtained showed three segments separated by characteristic steep slopes in the respective experimental isotherms. This could be indicative of uranium adsorption in multimolecular or cluster states onto talc. Moreover, the detected talc surface area of 3.5 m2/g was too small for adsorption of uranium as a monolayer. The surface area occupied by the maximum amount of uranium adsorbed (41.6 mg/g) as a monolayer was 58.3 m2/g.

► The uranium adsorption onto talc has been first investigated.
► Kinetic and equilibrium characteristics of uranium adsorption have been evaluated.
► The hypothesis of multimolecular adsorption of uranium has been suggested.
► The competitive effect of metals on uranium adsorption has been studied.