Thermo Catalytic Cracking of Waste Polyethylene Using a Hybrid Catalyst

Abstract

Scientific advancements in the latest era have lead widespread and endless growth in the production of plastic materials. This exponential development has made public distress over the environmental effect instigated by the waste polymer produced. The transformation of plastic waste to valuable products is gaining increasing attention. The aim of this investigation was to examine the aspects of catalytic degradation of polymer utilizing Fuller's earth clay AKA (Multani Matti), Dolomite, HZSM-5 as catalyst and various metal oxides as an additive. A number of experiments were done using diverse catalysts and temperature conditions. The plastic used was waste polyethylene bags whereas blended mixtures of (ZnO + clay), (Fe (III) oxide +clay), (Ni oxide + clay) and (Dolomite + ZnO + HZSM-5) were used as a catalyst. The plastic catalytically cracked under controlled conditions of 400 oC to 500 oC. The gas products formed during the catalytic degradation of polyethylene were then analyzed in gas chromatograph mass spectrometer (GCMS). The product varied distinctly on the type of catalyst and conditions used. The proportion of gas products i.e. propene, 1-butene, butane, butene and 1-pentene produced using fuller’s clay and dolomite zeolite mixture varied according to condition and w/w plastic to catalyst ratio. This is primarily due to different selectivity of dolomite mixture and fuller’s clay mixture. 450oC gave the maximum amount of product in the temperature range of 400 oC to 500 oC. Furthermore, the experimental setup developed in this work appeared to be feasible to produce low molecular weight hydrocarbons.