Grafted polyamide membrane for nanofiltration applications

A membrane made of a polymeric support, and an active layer with a polyamide grafted with a copolymer on the polymeric support. The copolymer is reacted units of a diallyldimethylammonium chloride (DADMAC), 3-(N,N-diallyl-N-methylammonio)propanesulfonate (DAMAPS), and N,N-diallyldodecane-1,12-diamine (DADA), and the copolymer is grafted to the polyamide with a linking molecule. Further, a method of making the membrane by dissolving an amine and the copolymer in water to form an aqueous solution, dissolving TMC in an organic solvent to form an organic mixture, pouring the aqueous solution onto a polymeric support and then pouring the organic mixture onto the same support for form a coated support, and heating the coated support to form a membrane.