New Technology Is Key Step Toward Big Gains in Plastics Recycling

Containers, containers, and other waste fill up landfills and litter the environment at an incredible rate. According to NREL, scientists have calculated that by 2050 there will be more plastic in the ocean than fish by weight.

The collaboration, led by NREL’s Greg Beckham and including OSU researcher Lucas Ellis, who was a NREL fellow during the project, combines chemical and biological processes to turn mixed plastic waste into “valorize” means to increase the value of something.

This research is based on the use of chemical oxidation to degrade various types of plastics. The method was developed ten years ago by the chemical giant DuPont.

“We have developed a method that uses oxygen and catalysts to break down plastic into smaller, more environmentally friendly chemical building blocks,” said Ellis, an assistant professor of chemical engineering. “From there, we can use biomodified soil microbes to consume these building blocks and ‘infuse’ them into biopolymers or building blocks for advanced nylon production. ”

Mr. Beckham, NREL Senior Scientist and Director of Biooptimized Technologies, an environmental consortium known as BOTTLE, is responsible for biooptimized technologies to prevent thermoplastics from ending up in landfills. plastic that cannot be recycled at all,” he said. This day. “

Beckham explains that modern recycling technology only works if the incoming plastic is clean and sorted.

Plastics can be made from a variety of polymers, each with its own chemical components. When polymer chemicals are mixed in trash cans or formulated together into certain products, such as multi-layer packaging, it is often necessary to separate the polymers before recycling, making recycling costly and virtually impossible.
“Our work has led to a process that can turn mixed plastics into a single chemical,” Ellis said. “In other words, it’s a technology that recyclers can use without sorting the plastic by type.”

The scientists applied the process to mixtures of three common plastics. Styrofoam is used in disposable coffee cups. Polyethylene terephthalate as a base for carpets, polyester clothing, and disposable beverage bottles. High-density polyethylene used in milk jugs and many other consumer plastics.

During the oxidation process, plastic breaks down into a mixture of compounds, including benzoic acid, terephthalic acid, and dicarboxylic acids. In the absence of artificial soil microorganisms, complex and expensive separations are required to obtain a pure product.

The researchers created the microbe Pseudomonas putida to biologically incorporate the mixture into one of two products. polyhydroxyalkanoates, a new form of biodegradable bioplastic and beta-ketoadipate that can be used to make high-performance nylon.
Testing the process with other types of plastics, such as polypropylene and polyvinyl chloride, will be a focus for future research, the researchers said.

“The chemical catalytic process that we use is just a way to speed up the natural process, so instead of taking hundreds of years to break down, we can degrade these plastics in hours or minutes,” said co-author Kevin Sullivan. NREL researcher.

Reference: Evaluation of Mixed Plastic Wastes Using Tandem Chemical Oxidation and Biological Injection, Kevin P. Sullivan, Allison Z. Werner, Kelsey J. Ramirez, Lucas D. Ellis, Jeremy R. Bassard, Brenna A. Black, David G. Brandner , Felicia Blatty, Bonnie L. Bass, Shwemin Dong, Steven J. Haugen, Morgan A. Ingram, Mikhail O. Konev, William E. Michener, Joel Miscoll, Isabelle Pardo, Sean P. Woodworth, Adam M. Gass, Yuri Roman – Reshkov, Shannon S. Stahl, Greg T. Beckham, Oct 13, 2022, Science.
DOI: 10.1126/science.abo4626

Funding was provided by the US Department of Energy’s Office of Advanced Manufacturing and Bioenergy Technology Administration, and the work was carried out through the BOTTLE consortium.

Scientists from the Massachusetts Institute of Technology (MIT), the University of Wisconsin-Madison and the Oak Ridge National Laboratory also participated in the study.

NREL is the US Department of Energy’s premier national laboratory for research and development in renewable energy and energy efficiency. It is managed in this sector by the Alliance for Sustainable Energy, LLC.