In this book I tried to give the brief introduction about membranes, membrane modules membrane processes and synthesis of membrane. A series of cellulose acetate/polyethylene glycol-600 membranes, with varying ratios were prepared by 2-stage phase inversion protocol. The permeation properties were studied by subjecting membranes in indigenously fabricated reverse osmosis plant. After optimization of different CA/PEG ratios, the membrane with highest salt rejection capacity was selected and modified with varying amount of silica. The Modified membranes were characterized for their permeation properties, hydrophilicity, compositional analysis, thermal stability, mechanical strength and morphological studies. Silica significantly influenced the permeation performance of composite membrane. The hydrophilicity was significantly enhanced by the addition of silica. The mechanical stability of the modified membranes, increased initially, but declined with further addition of silica. The results indicated that the incorporation of SiO2 content in the casting solution improved the fouling resistance of the membranes.
