Preparation of 3D graphene/iron oxides aerogels based on high-gravity intensified reactive precipitation and their applications for photo-Fenton reaction

Abstract

© 2018 In this work, we reported the preparation of 3D graphene/iron oxides aerogels (IO/GA) by in situ growth of iron oxide nanoparticles (IO) on the graphene oxides in high gravity rotating packed bed (RPB) followed by freeze drying treatments. The RPB was used to intensify the mass transfer and mixing during the adsorption and nucleation process of IO, guaranteeing highly homogeneous reaction conditions to the reactants. Thereafter, the IO nanoparticles obtained in the RPB route (IO/GA-RPB) exhibited an average size of 6 nm with uniform size distribution. By contrast, the IO nanoparticles prepared from traditional stirred tank reactor (IO/GA-STR) showed much larger particle size (33 nm). The 3D structured IO/GA-RPB nanocomposites were demonstrated to be efficient heterogeneous photo-Fenton catalysts for the degradation of methyl-blue. The kinetic studies of the catalytic reaction systems in the temperature range of 293 K-323 K and pH value of 1-7 were performed. The reaction rate constants and apparent activation energy were determined. The related catalytic mechanism of the photo-Fenton reaction was investigated. The excellent catalytic efficiency of the 3D-foam-structured heterogeneous IO/GA-RPB catalyst, along with the knowledge of the kinetics data, make them promising for in scale-up applications of photo-Fenton reaction.