Simultaneous electrosorptive removal of chromium(VI) and fluoride ions by capacitive deionization (CDI): Multicomponent isotherm modeling and kinetic study

Abstract

Abstract The aim of present study is simultaneous and individual removal of chromium (VI) (Cr(VI)) and fluoride (F) ions with activated carbon (AC) electrode by capacitive deionization (CDI). Capacitive deionization is recently developing and worldwide attracted technique due to less energy consumption and eco-friendly in use. AC electrode was fabricated and further it characterized by SEM, EDS, and cyclic voltammetry. The maximum electrosorptive removal of Cr(VI) and F were found to 97.1% and 94.20% for 10 mg/L binary feed at optimized flow rate 16 mL/min and 1.2 V. Effective regeneration electrode was observed after electrosoprtion of Cr(VI) and F. In mono component modeling Redlich Peterson model and Freundlich isotherm model were found best agreement with experimental results of Cr(VI) and F electrosorption. Non Modified R–P model and Extended Freundlich model among six applied multicomponent isotherm models found to good correlation with the experimental data for both Cr(VI) and F electrosorption. Pseudo first order kinetic model found good agreement experimental data for both Cr(VI) and F electrosorption. Thus CDI process could be used for simultaneous electrosorptive removal of low concentrated Cr(VI) and F binary feed system.