Monolithic silica columns are continuous porous and permeable materials that have a bimodal porous structure. Macropores (0.5-8 micrometers) and high bed porosity (0.6-0.9) allow fast convection, while thin silica skeletons (0.3-5 micrometers) allow rapid diffusion. The high mass transfer efficiency of monolithic columns has been used in analytical batch chromatography to achieve fast separation and high resolution. Only feasibility studies have been carried out for SMB applications using silica monoliths. The objective of this study is to explore the potential of SMB based on monolithic columns.

A new design method for monolithic SMB is developed in this study based on the concept of Standing Concentration Waves (SWD). A general rate model for monoliths is developed for SMB systems (VERSE-MONOLITH). The design based on standing waves is validated with the simulations using VERSE-MONOLITH.

This study shows that the maximum productivity of a monolithic SMB based on the commercial Prep-Chromolith columns is pressure limited. Permeability has to be improved to increase productivity by increasing bed porosity or skeleton diameter. Wave spreading due to mass transfer effects is an order of magnitude lower than in packed bed SMB, leading to much lower desorbent requirement for the same productivity. Axial dispersion is the major mechanism for wave spreading in the monolithic SMB.