Patent ID: 6723241
Filing Date: 2004-04-20
Classification: B01D

Abstract:
A composite membrane comprising a polyamide layer on a porous support wherein the polyamide layer retains at least 15 micrograms of phosphorous per gram of polyamide after washing by passing pure water across the membrane for 24 hours at 25Â° C. and a pressure of 70 pounds per square inch, and wherein the phosphorous comprises a phosphorous containing compound having solubility parameter of from about 15 to about 26 J1/2cmâˆ’3/2, wherein the phosphorous containing compound comprises a compound represented by the formula: wherein Z is the same or different and is selected from: X, Oâ€”Pâ€”(X)2, P(O)â€”X2, (P(â€”X))mâ€”Pâ€”X2, (Oâ€”P(â€”X))mâ€”Oâ€”Pâ€”X2, (P(O)(â€”X))mâ€”P(O)â€”X2, and (Oâ€”P(O)(â€”X))mâ€”Oâ€”P(O)â€”X2, and wherein at least one Z is selected from an aromatic group, P is phosphorous, O is oxygen, m is an integer from 1 to 5; Y is O or a non-bonded pair of electrons, X is the same or different and is selected from: R and R including one or more oxygen linkage(s), and R is the same or different and is selected from H (Hydrogen), and a carbon containing moiety.