Preparation and characterization of Fe-MCM-41 catalysts employed in the degradation of plastic materials

Fe-MCM-41 catalysts were prepared by two different metal loading methods. In the first one, iron was inserted in the siliceous framework during the hydrothermal synthesis; in the second one a MCM-41 sample was impregnated with iron nitrate in methanolic solution. Both samples were tested for plastics degradation activity towards polyethylene, polymethylmetacrylate and two polystyrene samples with different molecular weights. These tests were performed with the aim of being applied to the recover of the waste polymers, to be used as chemicals and fuels. Iron and carbon chemical states and atomic concentrations were determined by X-ray photoelectron spectroscopy (XPS), performed before and after the catalysis tests. The experimental results showed differences between the two Fe-MCM-41 catalysts, in particular in the iron chemical states before and after the catalysis. Different behaviour in the catalysis reaction is also revealed from the analysis of carbon species, that are different in the two catalysts and dependent on the type of the tested polymer.