Reverse osmosis membranes and process for their preparation.

摘要

An aromatic polyamide reverse osmosis membrane having a density of 0.15-0.30 g/cc with a salt rejection of 95% or more and exhibiting improved flux is disclosed. The membrane is prepared by casting a solution of an aromatic polyamide, partially drying the thereby formed pre-membrane to a polymer content of 30 to 50% by weight followed by quenching the pre-membrane with water within 5-10 seconds of leaving the drying step. Optionally, the membrane can be annealed in hot water.