Elimination of radionuclide uranium (VI) from aqueous solutions using an α-MnO2@CTS composite adsorbent

To effectively treat the contamination caused by radionuclide uranium (VI) in wastewater discharged from the nuclear industry, it is necessary to investigate novel nanomaterials with powerful adsorption capacities. In this study, a novel composite nanomaterial α-MnO 2 @CTS was successfully synthesized by coating nano manganese dioxide (α-MnO 2 ) with chitosan (CTS) using a straightforward method. The effects of the pH, ionic strength, presence of coexisting ions, time, temperature, cycle number and stability on U(VI) removal were investigated. The results showed that U(VI) elimination by α-MnO 2 @CTS was strongly dependent on the pH but weakly influenced by the NaNO 3 concentration, which indicated complexation on the inner-sphere surface. At pH = 6.0 ± 0.1 and T  = 298 K, α-MnO 2 @CTS had an adsorption capacity of up to 326.54 mg/g toward U(VI), which was consistent with the results of a Langmuir adsorption isotherm model. In various studies, the high removal rate of U(VI) by α-MnO 2 @CTS has been attributed to electrostatic attraction, and hydroxyl and amide groups introduced by CTS are also considered to play a key role in the adsorption process. In conclusion, α-MnO 2 @CTS can efficiently and rapidly adsorb U(VI) under acidic conditions, indicating broad application prospects for radioactive wastewater treatment.