Strategic conversion of industrial plastic waste into transportation fuel using iron and strontium containing metal waste as a catalyst

Abstract

Metal waste (MW) produced from different manufacturing companies has been considered a hazardous material and discarded in secured landfilling sites. The complicated chemical composition of MW made it difficult to be used as a beneficial material. When the hazardous waste is reused as a useful material, waste recycling with the minimization of hazardous waste landfilling could be achieved. In this study, MW from magnetic materials producing from facilities was utilized as a catalyst for conversion of polyethylene based industrial plastic waste (IPW) into more valuable transportation fuel. Without MW catalyst, IPW was converted into long chained HCs at 600 ˚C. Multi-zone pyrolysis further degraded them into shorter ones (average carbon length: C17), but the carbon chain length was still higher than those of diesel and aviation fuels. MW catalyst enhanced the C–C and C–H bond scissions, producing C7-16 HCs and H2 as major components. The catalytic activity was attributed to the presence of transition and alkaline (earth) metal (oxide) such as Iron (oxide), Strontium (oxide), and their alloys in MW. IPW plastic oil from catalytic pyrolysis (C13.22H25.86 for 45.99 MJ kg−1) had similar chemical formula and heating value of petrodiesel (C12.3H22.2 for 42.5 MJ kg−1) and jet fuel (C10.17H19.91 for 43.23 MJ kg−1). Therefore, this study demonstrated that the hazardous MW from industry could be employed as a catalyst for conversion of low-quality plastic oil into higher quality transportation fuel.