Nanofabricated chitosan/graphene oxide electrodes for enhancing electrosorptive removal of U(VI) from aqueous solution

Abstract

The radioactive pollution caused by uranium-containing effluents brings serious detriments to environmental safety and human health. Herein the chitosan/graphene oxide (CS/GO) electrodes were nano-fabricated for the effective electrosorption of U(VI) from aqueous solution. The cyclic voltammetry measurements were conducted to determine the specific capacitance of the CS/GO materials. The U(VI) electrosorption was performed on capacitive deionization (CDI) system. The results showed that CS/GO-4 presented best electrosorption performance for U(VI) among various CS/GO materials, which is associated with a well-balanced meso-/micro- porous structure for promoting ion transfer and superior conductivity for ion trapping through electrical double-layer (EDL) interaction. The isotherms could be described by Langmuir model, whereas the kinetics could be fitted by Langmuir model. The maximum removal capacity for U(VI) electrosorption by CS/GO-4 reached 271.2 mg/g at 0.9 V, which was almost double that achieved at 0.0 V. The electrosorption mechanism may involve in the formation of electrical double-layer (EDL) and the coordination of U(VI) by the amine and carboxyl groups of CS/GO materials. The electrosorption-desorption cycles further demonstrated that the potential application of CS/GO electrode materials for the electrosorptive removal of U(VI) from radioactive wastewater.