Despite well-intended efforts to keep plastic water bottles, packaging and other items out of landfills, only 9% of plastics in the U.S. are recycled. One of the big problems is that plastics are made up of different materials that when mixed together limit their reuse.
Scientists at Washington State University and the University of Washington announced this week that they have received a $2 million grant from the National Science Foundation (NSF) to help tackle the challenge.
The project includes research into technologies for taking mixed plastic waste and using a chemical process for breaking the plastics into their building-block monomers that can be put to other uses.
“The process is designed to address the grand challenge in the plastic industry: how to deconstruct co‑mingled municipal waste plastics selectively. It sounds very straightforward, but there are a lot of technical challenges,” said Hongfei Lin, who is leading the project, in a statement.
Lin has also been spearheading research that uses chemical processes for turning certain kinds of plastics into hydrocarbon products that can be used to make jet fuel or for other applications. That research is focused on plastics made of polyethylene, which in the form of polyethylene terephthalate is used to make plastic bottles.
Lin is an associate professor in WSU’s Gene and Linda Voiland School of Chemical Engineering and Bioengineering.
One of the downsides to chemical recycling — whether for recycling mixed plastics or turning polyethylene-based plastics into an ingredient for jet fuel — is that it can require a lot of energy and create greenhouse gases and other toxic chemicals. Lin has been working to make the process more energy efficient and environmentally friendly.
Mixed plastics can be manually separated, which is expensive, and then melted down and molded into new products. The recycled, melted plastics are of lower quality, the scientists say, compared the chemically recycled materials.
The co‑principal investigators on the NSF-backed project are Yong Wang, who is also from WSU’s School of Chemical Engineering and Bioengineering, and the UW’s Jim Pfaendtner, both of whom hold a joint appointment at Pacific Northwest National Laboratory.