AWWA ACE95062

The influences of solution chemistry and sorbent surface characteristics on the oxygen sensitivity of dissolved organic matter (DOM) sorption by granular activated carbon (GAC) were investigated. The oxygen sensitivities for sorption of Polymaleic Acid (PMA), Peat Humic Acid (PHA), and Laurentian Fulvic Acid, (LFA), were found to decrease with decreasing pH and with increasing ionic strength and calcium concentrations. The results suggest that linear, flexible and open DOM molecular configurations and direct interactions of DOM functional groups with GAC surface are important factors with respect to oxygen effects. Measurements of PMA and LFA sorption on different types of GAC surfaces indicate that oxygen sensitivity decreases markedly with increasing number of GAC surface functional (acid/base) groups, suggesting that polymerization occurs on the surface sites other than those containing acidic or basic surface functional groups. The two raw materials from which the experimental carbons were produced, wood and coal, were found to influence the oxygen sensitivity of DOM sorption differently.