Investigation of capacitive deionization process parameters on salt adsorption capacity via experimental design approach

Abstract

Process parameters of Capacitive Deionization (CDI) was investigated and optimized in this study. The effect of adsorption period (7-13 min), flow rate (5-20 ml min(-1)), and NaCl concentration (2-22 mM) on salt adsorption capacity was examined via Box-Behnken experimental design approach. A quadratic regression model (R-2 = 0.9987) was developed, revealing significant individual and binary effects between process parameters and salt adsorption capacity. The ANOVA results demonstrated its high significance with the p-value<0.0001. Optimal conditions varied with salt concentration, indicating significant interactions between the parameters. Maximum salt adsorption capacity occurred at 5 ml min(-1) flow rate and 13 min adsorption period for 22 mM NaCl, whereas for 12 mM and 2 mM NaCl concentrations, maximum adsorption capacity was obtained at the flow rate of 20 ml min(-1) and duration of 13 min. This study provided deep insights into CDI modelling and optimization, crucial for water treatment advancements.