Heterogeneous Fenton-type oxidative degradation of low-density polyethylene to valuable acid products using a nanostructured Fe–CeO2 solid solution catalyst

Abstract

The chemical conversion of waste plastic polymers to useful commodity chemicals has become crucial to helping tackle the issue of global plastic waste today. Polyolefins maintain the highest production rate and lowest recycling rate worldwide due to their inert chemical structures. This work shows the synthesis of solid-solution Fe–CeO₂ catalyst as an excellent heterogeneous catalyst for Fenton-type oxidative degradation of low-density polyethylene to achieve high yields of organic acids. The catalyst was synthesized in 3 molar ratios of Fe : Ce and it was found that the molar ratio of iron and cerium was crucial for catalytic performance with the Fe–CeO₂ 1 : 1 catalyst giving the highest yields of acid products. The catalyst achieved 91% mass loss and 71% organic acid at pH 7, with 1 wt% catalyst loading. The use of a multi-metal Fenton system resulted in a synergistic effect, displaying superior activity to systems with only one Fenton active metal. The heterogeneous nature of the catalyst allowed for easy recovery and demonstrated excellent recyclability in multiple cycles. The high recyclability performance was attributed to the stability of the solid solution structure.