Reverse osmosis composite membranes for boron removal

Abstract

Improved methods for reducing boron concentration in seawater or brackish water, while simultaneously maintaining or improving the salt rejection of membrane and flow performance of polyamide reverse osmosis (RO) membranes include contacting the water with a composite membrane comprising moieties derived from an aromatic sulfonyl halide, a heteroaromatic sulfonyl halide, a sulfinyl halide; a sulfenyl halide; a sulfuryl halide; a phosphoryl halide; a phosphonyl halide; a phosphinyl halide; a thiophosphoryl halide; a thiophosphonyl halide, an isocyanate, a urea, a cyanate, an aromatic carbonyl halide, an epoxide or a mixture thereof.

1 . A reverse osmosis method for reducing boron concentration in water containing boron, said reverse osmosis method comprising contacting the water with a composite membrane comprising moieties derived from an aromatic sulfonyl halide, a heteroaromatic sulfonyl halide, a sulfinyl halide; a sulfenyl halide; a sulfuryl halide; a phosphoryl halide; a phosphonyl halide; a phosphinyl halide; a thiophosphoryl halide; a thiophosphonyl halide, an isocyanate, a urea, a cyanate, an aromatic carbonyl halide, an epoxide or a mixture thereof. 
     
     
         2 . A reverse osmosis method according to  claim 1 , wherein the moieties are derived from an aromatic sulfonyl halide. 
     
     
         3 . A reverse osmosis method according to  claim 1 , wherein the moieties are derived from 4-nitrobenzenesulfonyl chloride. 
     
     
         4 . A reverse osmosis method according to  claim 1 , wherein the moieties are derived from 1,3-benzenedisulfonyl chloride. 
     
     
         5 . A reverse osmosis method according to  claim 1 , wherein the moieties are derived from 4-cyano benzenesulfonyl chloride. 
     
     
         6 . A reverse osmosis method according to  claim 1 , wherein the composite membrane additionally comprises a cross-linked hydrophilic polymer. 
     
     
         7 . A reverse osmosis method according to  claim 6 , wherein the cross-linked hydrophilic polymer is polyvinyl alcohol. 
     
     
         8 . A method for preparing a composite membrane comprising contacting under interfacial polymerization conditions an organic solution comprising a polyacid halide with an aqueous solution comprising a polyamine to form a polyamide membrane, said contacting being carried out on a surface of a porous base membrane, said organic solution further comprising an aryl sulfonyl halide. 
     
     
         9 . A method according to  claim 8 , wherein the organic solution additionally comprises a C 3 -C 8  cyclic carbonyl compound. 
     
     
         10 . A method according to  claim 9 , wherein the C 3 -C 8  cyclic carbonyl compound is cyclohexanone. 
     
     
         11 . A method according to  claim 8 , additionally comprising contacting the polyamide membrane with an oxidizing solution, such as sodium hypochlorite. 
     
     
         12 . A method according to  claim 11 , wherein the concentration of free chlorine in the sodium hypochlorite solution ranges from about 10 ppm to about 4000 ppm. 
     
     
         13 . A method according to  claim 8 , wherein the aryl sulfonyl halide is present in an amount ranging from about 0.01% to about 2% by weight. 
     
     
         14 . A method according to  claim 8 , wherein the aryl sulfonyl halide is 1,3-benzenedisulfonyl chloride or 1,3,6-naphthalenetrisulfonyl chloride 
     
     
         15 . A composite membrane prepared by the method of  claim 8 . 
     
     
         16 . A reverse osmosis method for reducing boron concentration in water containing boron, said reverse osmosis method comprising contacting the water with a composite membrane comprising moieties derived from an aromatic sulfonyl halide, a heteroaromatic sulfonyl halide, a sulfinyl halide; a sulfenyl halide; a sulfuryl halide; a phosphoryl halide; a phosphonyl halide; a phosphinyl halide; a thiophosphoryl halide; a thiophosphonyl halide, an isocyanate, a urea, a cyanate, an aromatic carbonyl halide, an epoxide or a mixture thereof,
 wherein the composite membrane is prepared by contacting under interfacial polymerization conditions an organic solution comprising a polyacid halide with an aqueous solution comprising a polyamine to form a polyamide membrane and contacting the polyamide membrane with an oxidizing solution;   said contacting being carried out on a surface of a porous base membrane,   said organic solution further comprising a C 3 -C 8  cyclic carbonyl compound and an aryl sulfonyl halide.   
     
     
         17 . A reverse osmosis method according to  claim 16 , wherein the oxidizing solution is a sodium hypochlorite solution.