Porous chitosan/biocarbon composite membrane as the electrode material for the electrosorption of uranium from aqueous solution

Abstract

The radioactive pollution owing to the discharge of effluents containing radionuclides brings serious toxicological effects on the ecological environment. In this work, the chitosan (CS) and biomass-resourced porous activated carbons (BC) composite membranes (CS/BC) were used as the electrodes for the electrosorption of U(VI) from aqueous solutions. The capacitive characteristic and electrosorption performance of the composite electrodes was systematically investigated. The CV curves of the CS/BC membrane showed normal dependency of scan-rate and U(VI) concentration, reflecting good removal capacity and kinetic rate for U(VI) electrosorption. The CS: BC mass ratios had significant effects on U(VI) electrosorption performance, and the CS/BC-2 is the best among various CS/BC electrodes owing to its good match of functional groups and mesoporous structure. The CS/BC-2 presented high removal capability of for U(VI) electrosorption (207.6 mg/g at the voltage of 0.9 V and pH 4.0, based on Langmuir model). The electrosorption involves in electrical double-layer formation, ion-exchange, complexation and physisorption. The cyclic electrosorption-desorption results and the XPS characterization further clarified this mechanism. The CS/BC-2 could also selectively adsorbed U(VI) from other co-existed metal ions in electrosorption. The results revealed the potential application of electrosorption process by using CS/BC electrodes in U(VI) solution for the cleanup of environmental pollution.