Electro-assisted adsorption of Cs(I) and Co(II) from aqueous solution by capacitive deionization with activated...

In this study, a new composite of activated carbon cloth/graphene oxide (ACC/GO) was prepared, characterized and used as electrode material for the electro-assisted adsorptive removal of Co²⁺ and Cs⁺ from aqueous solution. The ACC/GO composite was synthesized by a vacuum filtration method, and characterized by cyclic voltammetry and various surface characterization methods. Effect of applied voltage and initial concentration of Co²⁺ and Cs⁺ on their removal efficiency was examined. The kinetics and isotherms of Co²⁺ and Cs⁺ adsorption were investigated to explain the adsorption mechanism. At 0 V, the removal efficiency of Co²⁺ and Cs⁺ was 10.1% and 21.4%; at 1.2 V, electro-assistance increased the removal efficiency of Co²⁺ and Cs⁺ to 40.8% and 39.7%, respectively. Moreover, ACC/GO composite electrode had higher adsorption capacity compared to the pristine ACC electrode, due to its higher specific surface area and more oxygen-containing functional groups. The maximum adsorption capacity of Co²⁺ and Cs⁺ was 16.7 mg g^-1 and 22.9 mg g^-1, respectively at 1.2 V and 20 mg L^-1 by ACC/GO composite electrode. The modeling and experimental results demonstrated that the removal mechanism involved in physical adsorption, chemical adsorption, and electro-adsorption. Overall, the prepared ACC/GO composite electrode had high capacitive deionization performance in removing heavy metal ions from wastewater.