MASS TRANSFER PROCESSES DURING THE ADSORPTION OF SOLUTES IN AQUEOUS SOLUTIONS IN BATCH AND FIXED BED ADSORBERS.

A theoretical mass transfer model has been developed to describe the adsorption of solutes from aqueous solutions onto adsorbent particles in batch and fixed bed adsorbers. The theoretical model is based on the unreacted core theory and yields an analytical solution for batch adsorbers, providing the assumption of a pseudo-irreversible isotherm is applicable, and all operating and tie lines terminate on the monolayer. The effects of adsorbent mass and pollutant concentration are considered. The diffusion coefficient from the batch adsorption system may be used in an analytical model for predicting theoretical breakthrough curves in fixed bed adsorbers. The main data required in this model are geometric factors, physical properties of pollutant and adsorbent, an external mass transfer coefficient and an effective diffusion coefficient. The external mass transfer coefficient is predicted from available fixed bed correlations. The variables, which can be studied in fixed beds, include bed height, solution flowrate and pollutant concentration.