Novel malonamide-amidoxime bifunctional polymers decorated graphene oxide/chitosan electrode for enhancing electrosorptive removal of uranium (VI)

Developing the best electrode and exploring its electrosorption process are key to promoting the industrialization of uranium(VI) electrosorption. Herein, malonamide-amidoxime bifunctional polymers (MAFP) was incorporated into graphene oxide/chitosan (GO/CS) to prepare a high-performance composite electrode (MAFP/GO/CS) for U(VI) electrosorption. The as-prepared MAFP/GO/CS electrode displayed a more obvious porous structure, a larger specific surface area, an abundant amide and amidoxime group, as well as better hydrophilicity and electrochemical characteristics. This electrosorption experiment systematically examined the effects of voltage, electrosorption time, pH, and initial U(VI) concentration. According to the results, MAFP/GO/CS electrode had the maximum U(VI) electrosorption capacity of 260.58 mg/g at pH 6 and -1.2 V. It was found that Langmuir's and pseudo-second-order kinetic models of electrosorption were well suitable for simulating the U(VI) electrosorption kinetics and isotherms. A major contribution to enhanced electrosorptive U(VI) by MAFP/GO/CS electrode could be attributed to the synergetic coordination of U(VI) by amide and amidoxime groups in MAFP moieties. This work served as a good guideline for incorporating MAFP with GO/CS to fabricate a novel electrode for U(VI) electrosorption.