Highly reactive magnetite covered with islands of carbon: Oxidation of N and S-containing compounds in a biphasic system

[Display omitted] ► Heterogeneous oxidation of N and S organic compounds using amphiphilic catalyst. ► Magnetite covered with islands of carbon: an amphiphilic catalyst as a promising strategy. ► Amphiphilic catalyst presented high catalytic activity for oxidation of quinoline and DBT. In this work a series of magnetite were prepared by impregnating of natural goethite (limonite) with glycerol before thermal treatment under N2 flow at 300, 400 and 500°C. The formation of carbon spots (island) over magnetite was found. The magnetite was found to be the main phase after treatment at 400 and 500°C with high content of Fe2+, which is the active specie in a Fenton like system. Furthermore, iron oxide particles with magnetic and amphiphilic properties were formed, which are interesting for using as a catalyst in refineries. All materials presented high catalytic activities for oxidation of quinoline and dibenzothiophene in a biphasic reaction system (water/toluene).