Highly improved chlorine resistance of polyamide reverse membrane by grafting layers of graphene oxide.

• GO chemical grafting membranes demonstrate good chlorine resistance. • Chlorine resistance is enhanced with the increase of grafting times. • A large number of amide bond-active chlorine reaction sites are formed. Chemical grafting graphene oxide (GO) onto flat polyamide (PA) reverse osmosis membrane surface has been reported as a useful modification method for antibiological fouling. Here, we prepared an excellent chlorine resistance modified membranes by different layers GO grafting onto membrane surface. The influence of the layers number on the membrane separation performance and chlorine resistance was synthetically discussed. All modified membranes have good chlorine resistance, and the chlorine resistance is enhanced with the increase of grafting times. For example, NaCl rejection of pristine membrane drops from 96% to 46.2% while the GO 1 -grafted membrane drops from 95.7% to 59.2% and GO 5 -grafted membrane varies from 95.7% to 75.1% after 112 h exposure to chlorine. XPS results further prove that GO can react with chorine free radicals and protect PA fictional layers. Moreover, XPS analysis found that grafting method improved chlorine resistance more effectively than doping method by formation many choline attacking site amido bond. [ABSTRACT FROM AUTHOR]