Waste plastics-to-fuel using fly ash catalyst

Abstract

Suitable disposal pathways of waste plastics and coal fly ash have yet not been established which is a matter of great environmental concern. Waste low-density polyethylene (LDPE) and high-density polyethylene (HDPE) were degraded using a semi-batch reactor along with acid or alkali modified fly ash catalyst. The high yield of liquid fuel product (about 87.24 wt%) was achieved for low-density polyethylene at a polymer and catalyst ratio of 25 w/w. About 96% conversion was found with very few amount of gaseous fuels. Both of the waste plastics were degraded at 400–450\xa0°C. The liquid products were analyzed using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance ( 1 H, 13 C, and DEPT-135 NMR), and gas chromatography–mass spectrometry (GC–MS). Fly ash is an efficient catalyst to degrade waste plastic into light weight liquid (gasoline and kerosene) hydrocarbons. The NMR results accompanied by GC–MS data ensure that obtained fuels contain both aliphatic (saturated and unsaturated) and aromatic hydrocarbons. This plastic-to-fuel technology should be commercialized owing to be profitable and eco-friendly. Graphic abstract