Graphene oxide-supported nanoscale zero-valent iron composites for the removal of atrazine from aqueous solution

Graphene oxide-supported nano zero-valent iron (GO/nZVI) composites were successfully synthesized using a self-assembly method then characterized by various techniques. The results indicate that nZVI can be uniformly dispersed on the flat surface of GO and immersed into the wrinkles of GO, and both the defects structure, specific surface area and pore volume of GO/nZVI increased relative to those of GO and nZVI. These structure changes improve the reactivity of nZVI and adsorption capacity of GO, and alter the adsorption sites. The ability of GO/nZVI to remove atrazine was investigated by batch experiments according to various parameters. It was found that GO/nZVI can significantly increase the removal efficiency of atrazine compared to the pristine GO and nZVI and a synergetic effect occurred between GO and nZVI for atrazine removal. A combination of atrazine adsorption by GO and atrazine reduction by nZVI on GO/nZVI was proposed as the mechanism of atrazine removal, among the adsorption was the major process governed by pi-pi stacking of wrinkles, pore-filling of mesopores, and pi-pi EDA of GO defect sites. The results also suggested that GO/nZVI exhibited high reactivity under a wide pH range due to the mutual balancing effect between reduction and adsorption. In addition, GO/nZVI was easily separated from water and exhibited good stability. Therefore, GO/nZVI composites can be suitable as excellent materials for the treatment of contaminated water.