**2. Briefing on membrane separation**

Membrane separation is a technology in which selectively materials are screened out via pores or minute gaps presented in the molecular arrangement of membrane structure. Membrane separations are basically classified by pore size and by the separation driving force. These classifications are: microfiltration (MF), ultrafiltration (UF), ion-exchange (IE), and reverse osmosis (RO), and forward osmosis (FO) [11].

Membrane separations are primarily used to separate solids (either particulate or in solution) from liquid. The technology also used in effect liquid-liquid separation and gas-to-liquid infusion processes. Reverse osmosis (RO), ultra-filters (UF), and micro-filters (MF) are membrane technologies that employ pressure across the membrane as the driving force for separation (a trans-membrane pressure or TMP). Basically UF practical in concentrating and purifying virus, bacteria, fermentation broths, colloids, and particles, as well as dissolved high molecular weight polymer. Since membrane separations can also be accomplished at below ambient temperatures; they are suitable in the manufacture of degradable materials such as pharmaceuticals and foods. MF is engaged for separation and purification of suspended solids, colloidal particles, and bacteria from liquids and it is also used in the screening of particles and bacteria from gases. Non-filtration membrane technologies are dialysis and electro dialysis. Dialysis uses concentration differences as the separating driving force and the electro dialysis uses electric potential differences as the separating driving force for the separation. An artificial kidney is a specific example of dialysis where blood impurities are effectively removed for renal failure patients.
