Patent ID: 9248410
Filing Date: 2016-02-02
CPC Classification: B01D

Claim Text:
1. A forward osmosis membrane for seawater desalination in a forward osmosis mode, said forward osmosis membrane having a composite membrane structure of sequentially laminated layers comprising: a hydrophilic polymer layer having finger-like pores; and a polyamide layer; wherein the forward osmosis membrane satisfies both (i) a back diffusion of salts from a draw solution not more than 0.375 (μS/cm)/min·cm wherein the hydrophilic polymer layer contains 10 to 25 wt % content of a hydrophilic polymer including any one selected from the group consisting of hydrophilic polyacrylonitrile, polyacrylonitrile-vinylacetate copolymer (P-CO-PAN), and polyacrylonitrile-acrylic ester copolymer (CO-PAN); or the hydrophilic polymer containing 0.1 to 10 wt % of a sulfonated polysulfone-based polymer represented by formula 1 in combination with a polysulfone-based polymer; wherein A is any one functional group selected from: B is any one functional group selected from: m/(n+m) is 0.2 to 0.7; and x is 50 to 2,300.