Dendrimer modified composite magnetic nano-flocculant for efficient removal of graphene oxide

Graphene oxide (GO) as an emerging nanomaterial has been widely used in water purification. However, practical removal of GO from water environment and industrial waste liquid remains a critical challenge. Here, a poly (amide amine) dendrimer (PAMAM) modified composite magnetic nano-flocculant (Fe3O4@SiO2@PAMAM) was fabricated and a new strategy for removal of GO was proposed combining the advantages of flocculation with magnetic separation. Results showed that high removal efficiency of more than 82.41 % could be attained under the conditions of an initial GO concentration of 100 mg/L, flocculation time of 60 s, Fe3O4@SiO2@PA-MAM dose of 100 mg/L, and pH of 6.0. The maximum removal capacity of Fe3O4@SiO2@PAMAM for GO was approximately 238.10 mg g-1. Based on the charge neutralization and sweep flocculation, the prepared Fe3O4@SiO2@PAMAM demonstrated excellent application performance for removing GO in surface water, do-mestic sewage, and industrial waste liquid. A new magnetic nano-flocculant and an alternative technology strategy for treatment of GO was presented.