BATCH DYNAMIC ADSORPTION OF DIPEPTIDES ONTO REVERSED-PHASE SILICA-GEL

Batch adsorption kinetics of two dipeptides, N-carbobenzoxy-L-leucyl-glycine and N-carbobenzoxy-glycyl-L-phenylalanine, onto the reversed-phase C18 silica gel has been experimentally and theoretically studied in this paper. This dynamic adsorption process was described with a rate-equation model, in which the surface interaction rates is considered to be finite and follows an intrinsic kinetics of Langmuir type. The model is validated with the experimental batch kinetics data. The model parameters, rate constants and pore diffusivity, were estimated by matching the experimental data with the theoretical predictions obtained from numerical solution of the model equations. The dependence of these parameters on various factors including initial solute concentration, ratio of solution volume to adsorbent mass, pH and methanol content were examined.