Sustainable management of medical plastic waste through carbon dioxide-assisted pyrolysis

To address the challenges associated with medical plastic waste and to characterize its heterogeneity, non-recyclability, and potential biohazard risks, this study explored a carbon dioxide (CO₂)-assisted pyrolysis process as a sustainable disposal method. Medical plastic waste typically includes polypropylene, polystyrene, and polyvinyl chloride. To experimentally evaluate the functional reactivity of CO₂, we employed three pyrolysis setups (one-stage, two-stage, and catalytic processes). The technical advantages of using CO₂ over inert gases such as nitrogen (N₂) were demonstrated through pyrolysis tests. The results showed that energy production was enhanced under CO₂ conditions, with catalytic pyrolysis generating 146% more flammable gases compared to pyrolysis in an N₂ environment. The use of CO₂ also led to a reduction in the formation of toxic chemicals due to improved thermal cracking. The CO₂-assisted pyrolysis process exhibited net negative CO₂ emissions when a catalyst was present, as a substantial amount of CO₂ was consumed during the process. In conclusion, CO₂-assisted pyrolysis of medical plastic waste offers a sustainable management solution that maximizes the utilization of carbon resources.