Facile fabrication of magnetic reduced graphene oxide-ZnFe2O4 composites with enhanced adsorption and photocatalytic activity

Abstract

Magnetic reduced graphene oxide-ZnFe2O4 composites (RG/ZF) were successfully prepared through a simple chemical co-precipitation method, and their composition, structure, and morphology were characterized by XRD, Raman, SEM, TEM and STEM. These results indicated that the as-prepared RGO with some defects and few reactive groups containing oxygen possessed the few-layered crystal structure, and the ZnFe2O4 nanoparticles with spinel structure were homogeneously dispersed in the interlayer of graphene sheets. The interactions between two components had been investigated by TG and FT-IR. Importantly, kinetic researches indicated that the adsorption behavior of RG/ZF composite could be well described by the second-order kinetic model. Their adsorption effect on RhB conformed to the Langmuir model and belonged to the monolayer chemical adsorption, which were illustrated by thermodynamic experiment. In addition, RG/ZF composites with different mass ratio of RG to ZF (mRG/ZF) presented good photocatalytic activity, and their photocatalytic behavior could be described by the first-order kinetic model under different pH. Among all composites, the RG/ZF composite with mRG/ZF=0.4 showed the best photocatalytic activity under pH=1. However, the enhanced photocatalytic activity may arise from the effective separation of photogenerated e−-h+ pairs and the positive synergetic effect between two components. Moreover, the obtained optimum RG/ZF composite had the saturation magnetization (9.8747emu/g) enough to make it easy to be separated from solution by means of an external magnetic field. On the other hand, the antibacterial testing implied that the antibacterial properties of composite were depended on the mRG/ZF, and the RG/ZF with mRG/ZF=0.4 likewise presented the most excellent antibacterial activity, especially to the C. albicans (its IZD and MID was respectively up to 34.5mm and 12.5μg/mL). Finally, the possible mechanisms of photocatalysis and antibacterial have been discussed.