Reverse osmosis membrane

Abstract

There is provided a reverse osmosis membrane including a porous support; a polysulfone layer formed on the porous support and having pores formed in a surface thereof, pores having a diameter of 40 nm or greater accounting for less than 0.5% of total pores; and an active layer.

What is claimed is: 
     
         1 . A reverse osmosis membrane, comprising:
 a porous support;   a polysulfone layer formed on the porous support and having pores formed in a surface thereof, pores having a diameter of 40 nm or greater accounting for less than 0.5% of total pores; and   an active layer.   
     
     
         2 . The reverse osmosis membrane of  claim 1 , wherein a total area of the pores formed in the surface of the polysulfone layer accounts for 1% to 20% of a total area of the surface of the polysulfone layer. 
     
     
         3 . The reverse osmosis membrane of  claim 1 , wherein the pores formed in the surface of the polysulfone layer have an average diameter of 8.0 nm to 10.0 nm. 
     
     
         4 . The reverse osmosis membrane of  claim 1 , wherein the pores formed in the surface of the polysulfone layer is formed by using a solution including a mixed solvent containing two or more solvents having different solubility parameter values. 
     
     
         5 . The reverse osmosis membrane of  claim 4 , wherein the solution comprises:
 a polymer having a sulfonic acid group in an amount of 5 to 45 parts by weight, based on 100 parts by weight of the solution; and   the mixed solvent containing two or more solvents in an amount of 55 to 95 parts by weight, based on 100 parts by weight of the solution.   
     
     
         6 . The reverse osmosis membrane of  claim 4 , wherein the two or more solvents included in the mixed solvent have a difference in solubility parameter values therebetween of 0.1 to 15. 
     
     
         7 . The reverse osmosis membrane of  claim 4 , wherein the mixed solvent includes two or more solvents selected from the group consisting of dimethylacetamide, methyl acetate, hydrazine, trichloromethane, diiodomethane, trichloroethylene, styrene, 2-butanone, tetrahydrofuran, cyclohexanone, acetone, benzonitrile, isophorone, 2-ethyl-1-hexanol, dichloromethane, dibutyl phthalate, 1,4-Dioxane, 1,2-dichlorobenzene, 1,2-dichloroethane, 2-butoxyethanol, 1-bromonaphthalene, acetic acid, epichlorohydrin, benzaldehyde, morpholine, acrylonitrile, acetophenone, pyridine, 2-butanol, cyclohexanol, aniline, 2-methylpropyl alcohol, 3-methylphenol, N-methyl-2-pyrrolidine, 1-butanol, bromine, 2-ethoxyethanol, phenoxyethanol, 2-propanol, benzyl alcohol, dimethylethanolamine, 2-furanmethanol, acetonitrile, 1-propanol, 2-methoxymethanol, methanoic acid, N,N-dimethylformamide, nitromethane, ethanol, dimethyl sulfoxide, propylene carbonate, 1,3-butanediol, diethylene glycol, methanol, 1,2-propanediol, 2-aminoethanol, ethylene glycol, and γ-butyrolactone. 
     
     
         8 . The reverse osmosis membrane of  claim 4 , wherein the mixed solvent includes a first solvent having a solubility parameter value of 21(J/cm 3 ) 1/2  to 30(J/cm 3 ) 1/2  and a second solvent having a solubility parameter value different from that of the first solvent by 0.1 to 15, the first solvent and the second solvent being mixed in a ratio of 95:5 to 50:50. 
     
     
         9 . The reverse osmosis membrane of  claim 4 , wherein the mixed solvent includes N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). 
     
     
         10 . The reverse osmosis membrane of  claim 4 , wherein the mixed solvent includes N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) mixed in a ratio of 90:10 to 60:40. 
     
     
         11 . The reverse osmosis membrane of  claim 4 , wherein the mixed solvent includes N,N-dimethylformamide (DMF) and γ-butyrolactone (GBL) mixed in a ratio of 95:5 to 50:50.