Patents
This invention deals with a process of producing polyamide composite membranes for reverse osmosis. The polyamide composite membrane is made by coating a micro porous polysulfone support for about one minute with an aqueous solution containing 2-wt % m-phenylenediamine (MPD).The excess MPD solution is drained off, and coated support is dipped into a solution of 0.1 wt% Trimesoyl Chloride (TMC) in hexane for a minute. After draining the TMC solution, the resulting polyamide composite membrane is cured in an air-circulating oven at 40 to 90 C for 2-10 minute. The membrane is given post treatment with acid solution and dried in presence of surface- active agent and disinfectant. The resultant membrane exhibits a product flux of 30.5 gfd and a salt rejection of 95.5 % when tested at 2 to 5 psi pressure for an aqueous solution containing 0.2 % sodium chloride. This membrane can be operated in the pressure range of 200 to 400 psi and the salinity range of 2000 to 10000ppm.