Ratio, capacity permeating volume

Most commercial systems like Mustang from Pall and Sartobind from Sartorius make use of functionalized microporous membranes. The fibrils reinforced membranes are (pleated) layered around a porous core. The feed is forced to permeate through the membranes in radial direction. This approach results in high area to volume ratio. The 3M and Mosaic Systems approach is different. Instead of functionalization of a porous support they make use of already functionalized beads, which are embedded in a porous support. In this approach, the beads are responsible for the capacity and selectivity where the porous matrix controls the hydrodynamics. The 3M modules consist of stacked flat sheet or pleated membranes, while Mosaic Systems makes use of porous fibers in which the active particles are embedded (Figure 3.23). 

It is seen that a linear curve is not obtained with the use of (k ) values derived from the fully permeating dead volume and, thus, (k ) can not be used in the kinetic studies of columns. In contrast, the linear curve shown when using (k"), obtained from the use of the dynamic dead volume, confirms that (k e) values based on the excluded dead volume must be employed in all column kinetic studies. TTius, the excluded dead volume must be used for measuring mobile phase velocities and solute capacity ratios in all kinetic studies of columns and also in column design. 

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