Removal of thorium and uranium from aqueous solution by adsorption on hydrated manganese dioxide

The hydrated manganese dioxide (HMO) was synthesized by hydrothermal process using MnSO 4 and KMnO 4 . The adsorption of HMO for Th(IV) and U(VI) were investigated by batch static adsorption experiments. The HMO and MnO 2 were characterized by FT-IR, XRD and SEM. At the same time, the adsorption mechanism is discussed. The adsorption process was in line with the pseudo-second-order kinetic model and Langmuir isothermal model. The maximum adsorption capacities were Th ( T  = 308 K, C 0  = 200 mg L −1 , q max  = 218.34 mg g −1 ) and U ( T  = 308 K, C 0  = 200 mg L −1 , q max  = 55.19 mg g −1 ).