New research from Cornell University aims to ease the process of chemical recycling — an emerging industry that could turn waste products back into natural resources by physically breaking plastic down into the smaller molecules it was originally produced from. In a new paper, “Consequential Life Cycle Assessment and Optimization of High-Density Polyethylene Plastic Waste Chemical Recycling,” published in the Sept. 13 issue of the journal ACS Sustainable Chemistry & Engineering, Fengqi You, the Roxanne E. and Michael J. Zak Professor in Energy Systems Engineering and doctoral student Xiang Zhao detail a framework incorporating several mathematical models and methodologies that factor everything from chemical recycling equipment, processes and energy sources, to environmental effects and the market for end products.
The framework is the first comprehensive analysis of its kind that quantifies the life-cycle environmental impacts of plastic waste chemical recycling, such as climate change and human toxicity. Billions of tons of plastic have been produced since the 1950s, yet most of it — 91%, according to one often cited study — has not been recycled. While growing landfills and contaminated natural areas are among the concerns, the failure to reduce and reuse plastic is also seen by some as a missed economic opportunity.
That’s why the emerging industry of chemical recycling is capturing the attention of the waste industry and researchers like You, who is helping to identify optimal technologies for chemical recycling and providing a roadmap for the future of the industry. Not only does chemical recycling create a ‘circular economy,’ in which a waste product can be turned back into a natural resource, but it opens the door for plastics such as high-density polyethylene — used to produce items such as rigid bottles, toys, underground pipes, and mail package envelopes — to be recycled more commonly.