Inactivation performance and mechanism of Escherichia coli in aqueous system exposed to iron oxide loaded graphene nanocomposites

The challenge to achieve efficient disinfection and microbial control without harmful disinfection byproducts calls for developing new technologies. Magnetic-graphene oxide (M-GO) with magnetic iron oxide nanoparticles well dispersed on graphene oxide (GO) nanosheets exerted excellent antibacterial activity against Escherichia coli. The antibacterial performance of M-GO was dependent on the concentration and the component mass ratio of M/GO. The synergetic antibacterial effect of M-GO was observed with M/GO mass ratio of 9.09. TEM images illustrated the interaction between E. coli cells and M-GO nanocomposites. M-GO nanomaterials were possible to deposit on or penetrate into cells leading to leakage of intercellular contents and loss of cell integrity. The inactivation mechanism of E. coli by M-GO was supposed to result from both the membrane stress and oxidation stress during the incubation period. M-GO with excellent antibacterial efficiency against E. coli and separation-convenient property from water could be potent bactericidal nanomaterials for water disinfection. (C) 2014 Published by Elsevier B.V.