Electrochemical Adsorption of Cs(+) Ions on H-Todorokite Nanorods

[Image: see text] In this work, manganese oxide with a 3 × 3 tunnel structure was synthesized. Mg-todorokite was treated with HNO(3) to obtain H-todorokite, which was used as an electrode for adsorption of Cs(+) from aqueous solution by an electrochemical reaction. H-todorokite was electrochemically reduced to lower oxidation state to enhance its negative charge and simultaneously increase the amount of cations because of the charge compensation. The Cs(+) adsorption on H-todorokite was completed by a coupled electrochemical reaction (the redox reaction between Mn(3+) and Mn(4+)) and an ion-exchange reaction between Cs(+) and H(+) ions. Cyclic voltammetry measurements at different pHs and Cs(+) concentrations were performed. H-todorokite revealed high electrochemical adsorption capacity for Cs(+) because of the high crystallinity and stability of the materials, which reached 6.0 mmol g(–1) in 0.1 mol·L(–1) Na(2)SO(4) solution.