ACTIVATED CARBON ADSORPTION IN OXIDIZING ENVIRONMENTS

Molecular oxygen-induced enhancement in the adsorption capacity of GAC was investigated thoroughly from sorbate types point of view. Iosther m studies on phenol, o-cresol, and 4-nitrophenol at 23 degrees C showe d a 20-163% increase in retention capacities with the incremental capa city increasing with decreasing equilibrium concentrations. The increm ental capacity was strongly dependent on the DO to GAC mass ratio and the adsorptive capacity under anoxic conditions. The phenomenon was ob served when oxidizing agents such as hydrogen peroxide and potassium p ermanganate were used instead of molecular oxygen. CC-MS analysis perf ormed on GAC extracts suggested polymerization of adsorbates on the ca rbon surface as a potential reason for this enhancement phenomenon. Fo ur different aliphatic compounds namely chloroform, bromoform, 1,1,1 t richloromethane, and 1,1,2,2 tetrachloroethane were also studied. The results showed no significant effect on the adsorptive capacity of GAC for those aliphatics due to dissolved oxygen existence in the test en vironment. Significant enhancement was found in the case of wastewater samples from both domestic and industrial sources.