Reverse osmosis composite membranes for boron removal

A method for preparing a composite polyamide membrane comprising

• contacting under interfacial polymerization conditions an organic solution comprising trimesoyl chloride with an aqueous solution comprising phenylene diamine to form a composite polyamide membrane, said contacting being carried out on a surface of a porous base membrane, said organic solution further comprising cyclohexanone and an aryl sulfonyl halide selected from 1,3-benzenedisulfonyl chloride and 1,3,6-naphthalenetrisulfonyl chloride;
• and
• concentration of the aryl sulfonyl halide in the aqueous solution ranging from about 0.18% to about 0.71% by weight;
• and
• contacting the composite polyamide membrane with a sodium hypochlorite solution to form a treated composite polyamide membrane having salt passage less than or equal to 1.26% and A-value greater than or equal to 16.5.