Electrosorption based waste water treatment system using activated carbon cloth electrode: Electrosorption of benzoic acid from a flow-through electrolytic cell

An electrosorption based waste water treatment system including specially constructed flow-through electrolytic cell was designed. Electrosorptive removal of benzoic acid (BA) from dilute aqueous solutions in 0.01 M Na2SO4 onto activated carbon cloth (ACC) electrode was carried out with this system. Kinetics of both adsorption and electrosorption were followed by an online UV–Vis spectrophotometric analysis method. The data were successfully treated according to pseudo-first-order law and rate constants were determined. Appreciable increase, compared to open circuit adsorption, was obtained in the removal rate of BA by electrosorption. Effects of operating parameters such as applied potential and volumetric flow rate on electrosorption were examined. Optimum conditions for the process were found to be 30 mL min−1 for flow rate and +600 mV for polarization. The capacity of ACC under these conditions for electrosorption of BA was found as 180 (mg g−1) upon four successive electrosorption steps. An in-situ regeneration procedure applied at this saturation point caused 155 (mg g−1) of electrosorbed BA to electrodesorb upon −900 mV polarization, corresponding to about 86% regeneration of ACC.

Schematic representation of electrolytic cell used and the graph showing the concentrations of benzoic acid recorded during electrosorption steps (red circles) and the electrodesorption step (blue circles).Figure optionsDownload as PowerPoint slideHighlights
► We designed an electrosorption based waste water treatment system.
► We obtained enhancements in the removal rate of benzoic acid upon polarization.
► We achieved certain regeneration for carbon cloth electrode by electrodesorption.
► Electrosorption is a promising alternative method for waste water treatment.