Recycling Single Use Plastics to Useful Chemical Intermediates

Abstract

Polymers are extremely stable and with rising landfill costs, forthcoming extended producer responsibility tax and the drive towards a circular economy, there is an increasing need to redirect polymer waste from landfill/energy recovery towards enhanced recovery of the raw materials/feedstocks. The COVID pandemic has introduced a significant amount of personal protective equipment (PPE) single use plastics in the form of facemasks into our global ecosystem, which is increasingly becoming an environmental issue due to their increasing non-biodegradability and with declining landfill capacity, this makes plastic recycling a necessity. Chemical recycling stands out as a viable method of converting plastic waste into valuable products, especially liquid fuels (naphtha) and liquefied petroleum gas (LPG). Chemical recycling of plastics can also serve as a route to introduce circularity into the plastic supply chain. This research study is focused on investigating the use of heterogeneous catalysts (zeolites Beta and USY) for the conversion of polypropylene (PP) and single use facemasks into chemical feedstock using hydrocracking. Catalytic hydrocracking reactions were carried out between 270-330 °C at 20 bar hydrogen pressure for 30-60 minutes. The results indicates that USY zeolite was more effective than zeolite beta due to its higher selectivity to liquid products. Moreover, the presence of highly acidic catalysts can be used to suitably recycle polymers into useful hydrocarbons with C₃-C₁₆ product distributions.