Solid-liquid adsorption based on external mass transfer, macropore and micropore diffusion

A mass transfer model has been developed based on external film mass transfer, macropore diffusion and micropore diffusion to explain the adsorption of pollutants from aqueous solutions onto adsorbent particles. A computer program has been developed to facilitate analysis of the model in order that theoretical concentration decay curves may be compared with experimental data. A brief comparison has been made for the adsorption of Acid Blue 25 dye on chitin and phenol on carbon. However, the main purpose of the paper is to show the mathematical development of the model using the basic equations of the branched pore theory developed by Peel et al. (1981, A.I.Ch.E. J. 27, 26) and undertake a sensitivity analysis to study the effect of changing the four main parameters, namely, the external film mass transfer coefficient, the surface diffusion coefficient, the branched pore rate coefficient and the fraction of total adsorptive capacity in the macropores.