Influence of the ratio of Fe/Al2O3 on waste polypropylene pyrolysis for high value-added products

Thermo conversion technology has been considering as a promising one to realize the high value of waste plastics. However, low selectivity of target products limited the further utilization fundamentally. Herein, alumina supported with different iron ratio catalyst was introduced to improve the properties of products. The results show that the hydrogen in gaseous product increased dramatically with the increase in the iron ratio, and the maximum content was 82 vol% while the ratio of iron and alumina was 2:1. For liquid oil, the yield suffered from an apparent reduction, while the content of naphthalene increased first and then decreased and reached the maximum of over 70 area% when the iron and alumina was 1:2. Simultaneously, carbon deposits yield on catalysts increased with the increase iron ratio, and the maximum one of approximately 42 wt% was obtained from the catalyst with ratio of 1:1. Further research shows that the carbon deposits on the catalyst were composed of abundant carbon nanotubes (CNTs), varying from ~8 to 20 nm of diameters. This study presents a feasible strategy to deal with plastics.