CORVALLIS, Ore. – Let’s talk plastic and chemicals folks. To start, researchers, including an Oregon State University College of Engineering faculty member, have taken a key step. Especially toward greatly expanding the range of plastics and their chemicals that can be recycled.
The findings, published today in Science, are important. That’s because plastic and chemical waste is a massive problem. For that’s both globally and in the United States. Especially where only about 5% of used plastic is recycled. That’s according to the U.S. Department of Energy’s National Renewable Energy Laboratory, which led the study.
Packaging materials, containers, and other items are filling up landfills. These plastics have chemicals inside them. For they are littering the environment at a pace. So rapidly that scientists estimate by 2050, the ocean will have more plastic and chemicals by weight than fish. All most interestingly according to NREL.
The Research and Technology
A collaboration led by NREL’s Gregg Beckham and including Lucas Ellis, an OSU researcher who was an NREL postdoctoral fellow during the project, combined chemical and biological processes in a proof of concept to “valorize” mixed plastic waste. Valorize means to enhance the value of something.
The research builds on the use of chemical oxidation to break down a variety of plastic waste types. It’s a method from a decade ago by chemical industry giant DuPont.
“We developed a technology that used oxygen and catalysts to break down plastics into smaller, biologically friendly chemical building blocks,” said Ellis, an assistant professor of chemical engineering. “From there we used a biologically engineered soil microbe capable of consuming and ‘funneling’ those building blocks into either a biopolymer or a component for advanced nylon production.”
Beckham, a senior research fellow at NREL and the head of the Bio-Optimized Technologies to keep Thermoplastics out of Landfills and the Environment Consortium – known as BOTTLE – said the work provides a “potential entry point into processing plastics that cannot be recycled at all today.”
Current recycling technologies can only operate effectively if the plastic inputs are clean and separated by type, Beckham explains.
Plastics can be made from different polymers, each with its own unique chemical building blocks. When polymer chemistries are mixed in a collection bin, or formulated together in certain products like multilayer packaging, recycling becomes expensive and nearly impossible. That’s because the polymers often have to be separated before they can be recycled.
Simplifying Plastic Recycling
“Our work has resulted in a process that can convert mixed plastics to a single chemical product,” Ellis said. “In other words, it is a technology that recyclers could use without the task of sorting plastics by type.”
Researchers applied the process to a mix of three common plastics: polystyrene, used in disposable coffee cups; polyethylene terephthalate, the basis for carpets, polyester clothing, and single-use beverage bottles. Also, high-density polyethylene used in milk jugs and many other consumer plastics.
The oxidation process broke down the plastics into a mixture of compounds. It includes benzoic acid, terephthalic acid and dicarboxylic acids. Such acids in the absence of the engineered soil microbe would require advanced and costly separations to yield pure products.
The researchers engineered the microbe, Pseudomonas putida. That’s to funnel the mixture into one of two products biologically. For instance, polyhydroxyalkanoates which is an emerging form of biodegradable bioplastics. Also, beta-ketoadipate, which professionals can use in the manufacture of performance-advantaged nylon.
According to the researchers, trying the process with other types of plastics is the focus of upcoming work. That’s plastic, such as polypropylene and polyvinyl chloride.
“The chemical catalysis process we have used is just a way of accelerating a process that occurs naturally. So instead of degrading over several hundred years, you can break down these plastics in hours or minutes,” said co-author Kevin Sullivan, a postdoctoral researcher at NREL.
So instead of just having recycling bins for schools, these guys are learning how to break down plastics. All for a safer environment,
Funding was provided by the U.S. Department of Energy’s Advanced Manufacturing Office and Bioenergy Technologies Office. Moreover, the work is part of the BOTTLE Consortium.
In addition, scientists from the Massachusetts Institute of Technology, the University of Wisconsin-Madison and Oak Ridge National Laboratory also took part in the study.
In conclusion, NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. Finally, operation is for the department by the Alliance for Sustainable Energy, LLC.