Catalytic pyrolysis of waste polypropylene using low-cost natural catalysts

• Published in: Scientific reports Vol. 13; no. 1; p. 11766
• Main Authors: Eldahshory, A. I., Emara, Karim, Abd-Elhady, M. S., Ismail, M. A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20.07.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/898; 639/4077/4082; 639/4077/909; Calorimetry; Catalysts; Differential scanning calorimetry; Gas chromatography; Humanities and Social Sciences; Kaolin; Mass spectrometry; Mass spectroscopy; multidisciplinary; Polypropylene; Pyrolysis; Sand; Science; Science (multidisciplinary); Yard waste
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-37769-8

The objective of this research is to produce oil from the catalytic pyrolysis of waste polypropylene (WPP) using a low-cost natural catalyst. Three natural catalysts were examined, i.e. Kaolin, Hematite, and white sand. Different catalyst-to-plastic ratios were examined, i.e. 1:1, 1:2, 1:4, 1:6, and 1:8. The utilized catalysts were elementally analyzed using the XRF analysis and the surface area was analyzed by the BET multi-point method. The WPP thermal degradation behavior was investigated by the thermogravimetric analysis (TGA), then the generated liquid oil was analyzed using the gas chromatography-mass spectrometry (GC–MS) and the differential scanning calorimetry (DSC). Thermal cracking without a catalyst produced a yield of 70 wt% of liquid oil, and the maximum oil yield in case of using Hematite and white sand as a catalysts were 70 wt% and 68 wt%, respectively. However, the ratio of 1:2 of the Kaolin to the WPP produced the highest oil yield of 80.75 wt%, and the ratio of 1:8 of the white sand to the WPP produced the highest gas yield, i.e. 44 wt%. Using Kaolin in the catalytic pyrolysis of WPP produced oil with the lowest percentage of heavy oils, i.e. 25.98%, and the highest percentage of light oils, which is 25.37%, when compared to other catalysts such as Hematite and white sand. Kaolin has the lowest cost of oil production compared to Hematite and white sand, which is 0.28 $/kg of oil. Kaolin is an economical catalyst that improves the quality, as well as the quantity of the produced oil in comparison to Hematite, white sand and the non-catalytic case.