Sorption Kinetics in Finite-Bath Systems

Rates of sorption on activated carbon in rapidly agitated batch reactors can be influenced by both surface mass transfer and internal pore diffusion mechanisms. Mathematic interpretation of kinetic data is further complicated by the characteristic nonlinear equilibrium behavior of many sorbates. A conceptual kinetic model is developed using simplifying assumptions of irreversible adsorption and quasi-steady state. The model in its final form allows for straightforward calculation of diffusion and mass transfer coefficients. Experimental design was found to be critical for successful application of rate data to the model. Molecular size and shape were significant factors in predicting rate-limiting step behavior.