| The current procedure employed to design full scale activated carbon contacting systems is presented in detail and followed by a review of the more important process controls and operating parameters. Inherent limitations of the design procedure are identified, with the need to be able to accurately predict carbon sorption capacity from bench scale analysis determined to be the most important. Some of the more recent models developed to predict activated carbon sorption capacity were analyzed leading to the realization that even the most sophisticated dynamic models were based upon sorption capacities determined from classical isotherm procedures. The validity of the classical isotherm procedure and the potential for using easily measurable surface characteristics of the activated carbons were then evaluated in numerous experiments. The surface characteristics of the activated carbons measured were the pH at which the surface potential charge was zero (pHzpc) and the surface charge and surface potential over a wide range of pH values. From these experiments it was found that, for the activated carbons tested, grinding the samples prior to isotherm construction alters the surface properties measured and lead to erroneous results. Conversely, for the activated carbons evaluated, under the test conditions described, pHzpc was determined to be an accurate predictor of sorption capacity. |
