Competitive adsorption of trace organics on membranes and powdered activated carbon in powdered activated carbon-ultrafiltration system

An activated carbon adsorption model was developed to predict final permeate concentrations of a target trace organic compound (o-dichlorobenzene, DCB) under the variable influent concentration in powdered activated carbon-ultrafiltration (PAC-UF) system for drinking water production. The results were then compared with experimental DCB concentrations both in bulk and permeate. In the adsorption period, the DCB concentrations both in bulk and permeate were always lower than the predicted ones while the permeate concentrations were lower than the bulk ones regardless of membrane materials used and PAC doses. On the other hand, during the desorption period, the experimental values were higher or lower than the predicted ones depending on PAC dose and membrane used. The competitive adsorption and/or desorption of DCB between PAC and membrane itself resulted in this discrepancy, and this trend was more pronounced in a hydrophobic membrane.