Recent Advances in Polymeric Membranes for Pressure Driven Applications

Pressure driven membrane processes are widely used in various separation related applications ranging from production of drinking water from sea water and brackish water to separation of valuables from product streams or effluent management in industries. Research works are going on world over to develop novel membrane materials with superior performance having high selectivity, high throughput and better life. The research works cover all important fields of membrane separation including development of novel materials for membranes, development of new processes of making membranes and modification of membranes to achieve improved performances. In reverse osmosis (RO), to make membranes with better solute rejection and superior flux novel techniques are adopted like modification of reaction mixtures by added chemicals like multi functionary tertiary amine alcohol or polar compounds like triethylene glycol octyl methyl ether which eventually modifies the resulting membranes. For fouling resistant RO membranes methods have been developed where polymers resemble like brushes so that fouling is minimized. Membranes have been developed which are resistant to degradation due to oxidation. In nanofiltration (NF), in addition to development of fouling resistant membranes, new techniques have been developed for solvent resistant membranes. For microfiltration and ultrafiltration techniques have been developed for fouling resistant membranes by a novel layered coating of membranes. The present review describes some of the important works on membrane development, especially discovery of new polymeric membrane materials covering these aspects, disclosed in the patents in recent times.