Studies on the desalination of NaCl solution with activated carbon coating electrodes by electrosorption and kinetic analysis

摘要

In this paper a promising electrosorption approach called capacitive deionization (CDI) was discussed to relieve the crisis of water resources shortage. A simple CDI cell reactor was fabricated to study the performance of electrosorption experiments. A mixture containing activated carbon powder (ACP), binder poly vinylidene fluoride (PVDF) and conductive graphite powder at the mass ratio of 8:1:1(%) was dissolved in di-methylacetamide (DMAc) to form a slurry, then the slurry was cast on the current collector to manufacture activated carbon coating electrodes. The surface morphology and electrochemical performance of obtained electrodes were characterized using SEM and cyclic voltammetry (CV). From the SEM image, the electrodes were irregular grid-like porous materials, and both ACP and PVDF binder were bound together. The results of CV indicated that the electric double layer was existing and the specific capacitance was calculated. The adsorption rate and capacity of NaCl onto activated carbon coating electrodes at different bias potentials were measured and the electrosorption kinetics were also investigated. The kinetic analysis demonstrated that the electrosorption of NaCl on the activated carbon coating electrodes conformed to pseudo-first-order kinetics model.