DISSOLVED-OXYGEN EFFECTS ON EQUILIBRIUM AND KINETICS OF PHENOLICS ADSORPTION BY ACTIVATED CARBON

Phenol and o-cresol have been shown to undergo oxygen-induced polymeri zation reactions on activated carbon that enhance their adsorption. Fo ur different levels of dissolved oxygen (DO) were involved in the equi librium and kinetics studies undertaken. It was found that for both ph enol and o-cresol, the adsorptive capacities increase with the increas e in DO concentration. The quantities of dimers and trimers formed on the carbon surface were a function of the DO level. Phenol recovery ef ficiencies around 70 % and 25 % were found for anoxic and oxic isother ms, respectively. The additional capacity attained under oxic conditio ns was limited by the masses of DO and granular activated carbon (GAC) in the test environment. Two empirical relationships relating the oxi c capacity to the ratio of DO to GAC mass and the anoxic capacities we re developed. Batch studies have shown that the apparent surface diffu sivity coefficient for phenol in GAC decreased with increasing DO leve ls in the sorbate solution.