Structural effects on electrosorptive behavior of aromatic organic acids from aqueous solutions onto activated carbon cloth electrode of a flow-through electrolytic cell

A flow-through electrolytic cell, constructed specially for electrosorption processes, was connected to a UV–Vis spectrophotometer to examine the electrosorptive behaviors of benzoic acid (BA), phthalic acid (PA) and nicotinic acid (NA) from aqueous 0.01 M Na2SO4 solutions onto activated carbon cloth (ACC) electrode. Effect of pH on electrosorptive behavior of BA was determined. Competitive electrosorption from binary mixtures of BA and NA was carried out. In situ regeneration of ACC was examined by reversing the polarization direction upon which electrodesorption of 95% of electrosorbed NA was achieved. Kinetic data of both open circuit adsorption and electrosorption were found to obey successfully to pseudo-first-order law and rate constants were determined. Appreciable increase in the removal rate of aromatic organic acids was achieved by electrosorption compared to open circuit adsorption. Rate constants for electrosorption at +600 mV polarization were found to decrease in the order of NA > PA > BA.

► We designed an electrosorption based waste water treatment system.
► Electrosorptive behaviors of aromatic organic acids are determined mainly by their dipole moments.
► We achieved in situ electrochemical regeneration of activated carbon cloth electrode.
► Electrosorption is a promising alternative method for waste water treatment.