Development of Solutions to Two‐Resistance Mass Transport Models Based on External and Pore Diffusion. Part I: Theoretical Development

A two‐resistance mass transfer model has been developed to describe the adsorption of various pollutants onto adsorbents in batch adsorbers. The mechanism is based on external liquid‐phase mass transfer and pore‐diffusion controlling internal mass transport. A previous analytical modef⁻¹ was developed for a pseudo‐irreversible isotherm, but it was only applicable to systems in which operating lines and tie lines terminated on the isotherm monolayer. The application of the original model has been extended by incorporating several curve fitting equations into the analysis and differentiating them, thus enabling mass transfer coefficients to be predicted for operating lines over the whole range of the equilibrium isotherm. A comparison of the curve fitting equations was made to test which, if any, gave the 'best‐fit' to experimental data.