Patent ID: 6177011
Filing Date: 2001-01-23
Classification: B01D,C02F,Y02A

Abstract:
A reverse osmosis composite membrane comprising:a sponge layer; anda separation layer formed on a surface of the sponge layer, wherein said separation layer comprises an aromatic polyamide, wherein a surface of the separation layer has a coating layer of at least one substance selected from the group consisting of an electrically neutral organic substance and an electrically neutral polymer, wherein a surface zeta (.zeta.) potential of the coating layer is controlled within.+-.10 mV at pH 6, wherein the reverse osmosis composite membrane has a flux of 0.6 m.sup.3 /m.sup.2 /day or more in a reverse osmosis test conducted by feeding a 1,500 ppm NaCl solution at a pressure of 15 kg/cm.sup.2 and a temperature of 25.degree. C., and wherein the reverse osmosis composite membrane before coating has an absolute value of the surface zeta (.zeta.) potential greater than.+-.10 mV in the range of pH 5 to 11 and has a flux of 0.6 m.sup.3 /m.sup.2 /day or more in a reverse osmosis test conducted by feeding a 500 ppm NaCl solution at a pressure of 7.5 kg/cm.sup.2 and a temperature of 25.degree. C.