Catalytic combustion of methane over red mud-based catalysts

Three iron-based catalysts were prepared from waste materials from the aluminium industry (red mud (RM)) by dissolution–precipitation methods, followed by calcination in air at 500 °C for 2 h. The activity and stability of those materials for the catalytic combustion of methane was studied at atmospheric pressure, temperatures between 300 and 626 °C and space time between 106 and 526 g h/mol of methane (WHSV=48 h−1), and compared to that of hematite and a Cu-Cr-Ti commercial catalyst. The kinetics of the reaction was successfully modelled considering pseudo-first order dependence on methane partial pressure. Superficial characterisation of fresh and used catalysts were carried out by BET, X-ray diffraction (XRD) and temperature programmed techniques. Results obtained indicate that red mud activated by the method of Pratt and Christoverson exhibits higher catalytic activity and good thermal stability.