Cobalt-doped Graphene-supported Nanoscale Zero-valent Iron: Removal of Rhodamine B solution and mechanistic study

Abstract

nZVI materials loaded on GO have been applied to the treatment of difficult-to-degrade organics due to their higher electron transfer rate. However, cobalt doping of GO/nZVI composites and the effect of the doped materials on difficult-to-degrade organics are not known. In this work, Cobalt-doped Graphene-supported nanoscale Zero-valent Iron (GO/nZVI-Co) was successfully synthesized via the liquid-phase reduction-suspension self-assembly method, which was composited with theoretical mass ratio of GO:nZVI:Co = 1:2:0.08. And GO/nZVI-Co was used as efficient heterogeneous catalyst for degradation of Rhodamine B (RhB) via H2O2. Characterization results show that nZVI and Co particles were successfully loaded on GO nanosheets increasing the dispersibility of particles. Under the optimal reaction conditions(the mass ratio of GO: nZVI = 1:2 and Co doping is less than 1/5), the RhB degradation rate was as high as 98.28 %. The degradation pathways of GO/nZVI-Co-HP system could better explained by the secondary kinetic model and GC–MS spectru. The main effect of cobalt doping in the GO/nZVI-Co-HP system is to increase the adsorption properties of the material on H2O2, and this facilitates the contact reaction of nZVI with H2O2. In this study, a GO/nZVI-Co material with improved electron transfer efficiency was prepared and its removal mechanism of pollutants was elucidated to provide relevant theoretical support for the treatment of difficult-to-degrade wastewater.