Journal of Applied Chemical Science International

The growing challenge of plastic waste pollution, coupled with the limited efficiency of conventional waste management techniques in Nigeria, drives the exploration of thermal and catalytic pyrolysis. These methods present an alternative, more efficient solution for plastic waste conversion into valuable hydrocarbons, with the catalyst improving product yield and quality. However, commercial zeolites presently used are often expensive and require complex synthesis procedures, thus limiting their widespread use in industrial applications. This study investigates the thermal and catalytic pyrolysis of waste plastic bags from polythene and Styrofoam food packaging made from polystyrene into liquid fuel using Zeolite X synthesized from clay sourced locally from konno-boue in Khana local government area of Rivers State. The study commenced with the synthesis of Zeolite X through pretreatment the kaolin clay and calcination processes. The synthesized Zeolite X catalyst was characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM) to confirm its structural integrity and catalytic potential. The catalytic and thermal pyrolysis of polythene and polystyrene was conducted in a fixed-bed pyrolysis reactor, with temperatures ranging from 300 °C to 600 °C. Parameters such as the catalyst-to-plastic ratio and reaction temperatures were varied to optimize the product yield. The products obtained include: liquid oil, solid char, and gases, with their resultant yields specified. Results indicated that thermal pyrolysis in the absence of catalyst yielded 66.5% liquid fuel, while catalytic pyrolysis produced a lower yield of 28 % liquid but significantly increased the gas output to 61 %. This enhanced gas production with Zeolite X is attributed to the catalyst's role in breaking down larger hydrocarbon chains more effectively. The liquid fuel product obtained from the catalytic pyrolysis of polythene and polystyrene shows that catalyst to feed stock ratio of 1:4 was effective. This increased the yield of gas from 7.0 % to 61 %. The temperature range for catalytic pyrolysis was 200 °C to 280 °C, while thermal pyrolysis required higher temperatures of 300 °C to 395 °C, highlighting the energy savings afforded by catalytic processes. Further analysis using Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography (GC) Total Petroleum Hydrocarbons (TPH) indicated the fuel quality, with a higher content of light hydrocarbons such as alkanes and alkenes in catalytic pyrolysis, suitable for use as an alternative fuel. The locally sourced Zeolite X catalyst demonstrated strong potential for improving the efficiency and selectivity of the pyrolysis process, making it a viable solution for plastic waste management and fuel production.