Reducing fouling of RO membranes by redox-initiated graft polymerization

In previous publications we described a simple method for surface modification of commercial composite polyamide RO membranes and characterized the modified membranes thoroughly. The, procedure involves radical grafting with a redox system consisting of potassium persulfate/sodium methabisulfite in an aqueous solution at room temperature. Three membranes, BW-30, SW-30 and CPA-2, were modified and the products were then subjected to ATR-FTIR The ATR-FTIR technique was particularly valuable in providing information about degree of grafting and the microstructure of grafted chains. Both acrylic and sulfo-acidic monomers and neutral monomers such as polyethylene glycol methacrylate were used to demonstrate the wide possibilities of the method in terms of grafting of different monomers and initiators. It was shown that some of the modified membranes conserved their previous operating characteristics, flux, or rejection, but exhibited a higher resistance to humic acid.