Reduction of Aqueous HOCl with Activated Carbon

A mathematical model describing the unsteady state of chlorine removal from water by activated carbon is developed and tested. Constants in the model, which account for intraparticle diffusion and surface reaction, are determined from semibatch experiments in which the level of free chlorine, present in all cases as HOCl, is maintained constant. The resulting model is tested for its adequacy in describing experimental results obtained from a closed batch reactor and from a fixed-bed reactor for several sets of conditions including different particle sizes. Very close agreement is demonstrated between experimental results, in the form of effluent chlorine concentration versus time, and model predictions.