Effects of electrochemical treatment of granular activated carbon on surface acid groups and the adsorptive capacity for phenol

An electric current was passed through a granular activated carbon (GAC) column to investigate changes in the surface characteristics of the GAC and the adsorptive capacity for phenol. Using potentiometric titration, it was observed that the GAC was less acidic after cathodic treatment and more acidic after anodic treatment. Oxic and anoxic isotherms were compared using statistical methods to evaluate changes in the adsorptive capacity of GAC for phenol. Under oxic conditions, the adsorptive capacity of GAC decreased after anodic and cathodic treatment. Under anoxic conditions, a decrease in adsorptive capacity in the lower range of phenol concentrations investigated was observed after anodic treatment, while cathodic treatment may not have significantly altered the adsorptive capacity. The observed changes in adsorptive capacity could not be definitely correlated with the observed changes in the measured surface acid group concentrations in this study.