CATALYTIC CRACKING OF TOLUENE USING RED MUD: HYDROGEN EVOLUTION AND CARBON FORMATION

Toluene has been used as a model tar compound in many cracking and reforming studies in the context of biomass gasification and pyrolysis. Low cost alternate catalysts such as biochar, limonite have been studied. Toluene has also been used in chemical vapour deposition of carbon nano tubes. In this study, red mud waste from the aluminium industry without any pre treatment was used as a catalyst for toluene cracking. The hydrogen evolution and nano carbon formation were studied. The reduction behaviour of the catalyst in hydrogen showed conversion of iron hydroxide and oxide to iron above 700 ?C. Hydrogen formation rate was maximum at 800 ?C after around 7 h and subsequently reduced with time. Depending on the carbon content, the post reaction catalyst was comprised of reduced iron oxides (magnetite, wustite) and mixture of iron, iron carbide and graphitic carbon. Carbon content up to 46% was obtained and the deposited carbon was in the form of nano fibers. While red mud has been used in catalytic steam gasification and pyrolysis of biomass, the hydrogen evolution using red mud and toluene has not been reported.