Abstract

Dialysis is a membrane separation process in which permeating species diffuse across a selective barrier in response to a difference in concentration. Less efficient than other industrial membrane unit operations, dialysis finds appeal chiefly in those biotechnology and food processing applications requiring gentle, isothermal, nondenaturing operating conditions. The popularity of dialysis as general laboratory technique for the separation, concentration, and purification of macromolecules has waned. In contrast, microdialysis, a continuous technique for estimating solute concentration in vivo without blood sampling, is increasing in importance, especially in neuropharmacological protocols. By far the largest and most formidable application of dialysis is for the chronic intermittent extracorporeal therapy of end stage kidney disease. In 1992, over 60 million highly optimized disposable hemodializers were produced to support a population of over 400,000 patients with renal failure.