SEPARATION BY MEMBRANES.

Abstract

A review is presented of membrane processes in general, with the exception of electro-membrane processes. The authors' aim is to discuss the aspects common to all membrane processes as well as the essential differences between them. The following processes are examined: reverse osmosis, ultrafiltration, gas permeation through porous or diffusion membranes, pervaporation and liquid membrane techniques. In liquid systems, mass transfer at the membrane surface proves to be the limiting factor. Conditions on the permeate side tend to influence flux and quality of the permeate only when a considerable pressure drop does occur. A typical example is that of hollow fiber modules. It is shown how the permeability and dimensions of the membrane require selective adjustment in order to establish maximum flux.