Determination of intraparticle transport parameters for multicomponent adsorption

This paper is devoted to the problem of determining intraparticle transport coefficients for multicomponent adsorption from experimental kinetic curves. Due to thermodynamic and kinetic interactions between the mixture’s components, this task is more difficult than for single component systems. As an example, the kinetics of adsorption on activated carbon of binary mixtures of phenol and indole from aqueous solutions was studied in a continuous stirred tank adsorber (CSTA). To describe the intraparticle transport of this system, the surface diffusion model using a linear driving force (LDF) was applied. For determining the matrix of the unknown kinetic parameters of the LDF-model, the application of three independent mathematical methods is discussed. Firstly, a semi-analytical calculation (SA) of the intraparticle transport parameters by solving a system of linear equations on the basis of an empirical description of experimental kinetic curves is put forward. Secondly, a non-linear regression (NR) method for parameter estimation was applied. The third method is a non-linear regression which, in contrast to the SA and NR methods, guarantees the stability of the system of differential equations in the steady state of the process (NRS)