Optimization of preparation conditions of composite electrodes for selective adsorption of vanadium in CDI by response surface methodology

Abstract

In this work, a novel composite electrodes D314/activated carbon (AC) were prepared by D314 ion-exchange resin and activated carbon (AC) for the preferential adsorption of vanadium ion in capacitive deionization (CDI) technique. The conditions for preparing D314/AC composite electrode had been optimized using Response surface methodology (RSM). The vanadium (V) preferential adsorption characteristics, as affected by the weight ratio of resin to AC, the content of binder and the particle size of resin, were acquired by the Box-Behnken experimental design. In the optimized conditions, the average values of the adsorption amount of V, separation efficiency of V to iron (Fe) and aluminium (Al) reach 106.89±3.03mg/g, 2.08±0.08, 10.55±0.45, which were among the 95% confidence intervals (92.86, 110.10), (1.79, 2.16), (7.91, 12.24) of the predicted optimal value. The particle size of resin has the largest impact on the three response values, which will affect the specific surface area and specific capacitance of the composite electrode.