Membrane and Desalination Technologies - TCE Moodle Website

240 L.K. Wang et al.
Fig. 6.1. Filtration application guide for membrane separation processes.
1. Flux, which is the rate of transport of solvent or solution through the membrane
2. Rejection, which is the degree of separation of a particular feed component
There are five major variables that affect the two basic process parameters (8):
1. Driving force in terms of applied transmembrane pressure (TMP) and/or electric voltage/current
2. Flow velocity which affects turbulence and mass transfer coefficient
3. Process water temperature which has effects on physical properties, such as density, viscosity,
diffusivity, osmotic pressure, surface tension, and others
4. Feed stream characteristics in terms of particle concentration, particle size, viscosity, molecular
weight, molecular configuration, ionic charges, and fouling potential
5. Membrane module in terms of materials, pore sizes, membrane configuration membrane ionic
charges, and feed compatibility
2.2. Membrane Modules and Equipment
There are basically six different designs of membrane modules (12, 13):
1. Tubular modules with channel diameters greater than 3 mm
2. Hollow fiber or capillary modules made of self-supporting tubes, usually 2 mm or less in internal
diameters
3. Plate modules
4. Spiral-wound modules
5. Pleated sheet modules
6. Rotary modules