The researchers revealed the surprising benefits of adding water during polyolefin depolymerization when using ruthenium (Ru)-based catalysts.
After synthesizing and experimenting on various Ru-based catalysts on different supports, the team found that catalysts with both metal and acid sites exhibit dramatically improved conversion rates when water is added to the reaction mixture. "The addition of water alters the reaction mechanisms, promoting pathways that enhance catalytic activity while suppressing coke formation," explains Dr. Ro, "This dual role improves process efficiency, extends catalyst lifespan, and reduces operational costs."
The researchers investigated the reaction mechanisms in detail, shedding light on the effect of Ru content and the proximity and balance between metal and acid sites. Under optimal conditions, Ru/zeolite-Y catalysts showcased a 96.9% conversion rate for polyolefins.
Finally, to explore the viability of this type of catalytic recycling, the team conducted a techno-economic analysis and a life cycle assessment of the proposed approach. The results clearly underscored the potential of implementing a real commercial-scale process using Ru/zeolite-Y catalyst. "The addition of water not only enhances carbon efficiency, it improves economic and environmental performance, also increases the conversion of polyolefins to valuable fuels like gasoline and diesel," highlights Dr. Ro. Adding further, he says, "This approach thus represents a viable alternative to conventional waste management practices and offers a solution to reduce landfill and ocean pollution caused by polyolefins—the largest contributor to plastic waste."
Overall, this breakthrough in catalytic depolymerization could revolutionize how we deal with plastic pollution and help us efficiently deal with this serious environmental threat. The research team has high hopes that this technology will evolve over the next few years to the point that mixed plastic waste can be processed without pre-sorting, making recycling efforts more cost-effective and simpler to implement. "By demonstrating a sustainable and economic approach to transforming plastic waste into valuable resources, our research could help drive policy changes, inspire investment in advanced recycling infrastructure, and foster international collaborations to address the global plastic waste crisis. Over time, these advancements promise cleaner environments, reduced pollution, and a more sustainable future," concludes Dr. Ro on an optimistic note.
