PERFUSION CHROMATOGRAPHY - PERFORMANCE OF PERIODIC COUNTERCURRENT COLUMN OPERATION AND ITS COMPARISON WITH FIXED-BED OPERATION

Simulation studies using mathematical models that describe the single-component adsorption of bovine serum albumin into spherical bidisperse perfusive and spherical bidisperse purely diffusive anion-exchange porous adsorbent particles in a single-column fixed-bed system and in a two-column periodic countercurrent system in which the adsorbent is equally distributed over two beds are presented. The total length of the two-column periodic countercurrent system is equal to the length of the single-column fixed-bed system, and studies are performed for different values of the intraparticle Peclet number, Pe(intra), and of the microsphere diameter, d(m). In the single-column fixed-bed system, the percentage utilization of the adsorptive capacity of the adsorbent increases as d(m) decreases and Pe(intra) increases. The results indicate that the two-column system under periodic countercurrent operation provides higher values for the percentage utilization of the adsorptive capacity of the adsorbent than all the values of the percentage utilization of the adsorptive capacity of the adsorbent obtained from the single-column fixed-bed system for all values of d(m) and Pe(intra) examined in this work. It is an interesting result that the percentage utilization of the adsorptive capacity obtained from a two-column periodic counter-current system having purely diffusive (Pe(intra) = 0) adsorbent particles with the largest microsphere size, d(m), studied in this work is found to be higher than the percentage utilization of the adsorptive capacity obtained from a single-column system that uses perfusive adsorbent particles with the smallest microsphere size, d(m), and the largest intraparticle Peclet number, Pe(intra), studied in this work. The simulation studies with the two-column periodic countercurrent system also provide the following interesting result: the factors of economic significance in the two-column system under periodic countercurrent operation, namely the time between column switches and the degree of saturation of the column removed, are nearly independent of the values of the microsphere diameter, d(m), and the intraparticle Peclet number, Pe(intra).