You may see a plastic bag and think groceries, but Vilas Pol thinks batteries. 

The Argonne National Laboratory scholar has developed a new technology that converts the plastic sacks into carbon nanotubes, a component used in lithium-ion batteries that power everything from cell phones to cars. Pol calls the process “upcycling” because the finished product has a much higher value than the initial materials.

Not only is the process he’s created a cheaper way to develop nanotubes, Pol said, it could be an environmental game-changer.

“Many times, when I go to the grocery store, I get 10 or 15 bags,” he said. “The problem (of recycling them) is very serious, not just here but in developing countries. They just dump them in the Dumpster, and they don’t decompose at all.”

The idea to turn plastic bags into something more sprang from a report Pol read two years ago about the bags being banned from San Francisco’s grocery stores and pharmacies. Pol holds a director’s post-doctoral fellowship in chemical sciences and engineering at Argonne, which is near Lemont and is operated by the Department of Energy, and he thought he could use his expertise to find a better alternative to tossing the flimsy carriers.

“My supervisor asked if I could do something with plastics, and I said, ‘It might take time,’ ” Pol said. “He said, ‘Time is no problem.’ ”

Pol considered the properties of plastic, which is composed of carbon, hydrogen and sometimes oxygen, and decided the best use for the bags would be to harvest the carbon to grow nanotubes. Using cobalt acetate as a catalyst, he cooked the bags at 700 degrees Celsius until the plastic broke down, causing the carbon in the plastic to grow as nanotubes on the cobalt particles.

Creating enough nanotubes to power a cell phone takes less than one plastic bag, Pol said, and the process winds up costing less than traditional ways of creating nanotubes, which usually must be created in a vacuum. Better yet, the technology can be applied to several types of plastic, not just plastic bags.

“You can use water bottles or plastic cups,” Pol said.

Although cobalt acetate is relatively expensive, Pol pointed out the material can be recovered when the batteries are recycled. Pol also found that performing the process without cobalt acetate still yields a useful result – carbon spheres that can be used in printer ink.

Right now, plastic bags collected for recycling are used most frequently to create a wood-plastic hybrid used in decking or patio furniture, said Mike Mitchell, executive director of the Illinois Recycling Association. But while more grocery stores around Illinois are starting to offer plastic bag recycling, plenty of bags still wind up in landfills, where they will sit forever.

“They’re definitely an issue,” he said. “They’re hard to recycle. Curbside collectors don’t want them in the curbside program because they’re so lightweight and they get caught in air currents (in recycling centers.) … Then it becomes for residents, ‘Well, what do I do with this?’ ”

New options for plastic bags would be a welcome addition for the recycling industry, Mitchell said.
“It’s the more, the merrier for this type of stuff,” he said.

For the technology to work on a large scale, Argonne will need to work with engineers to design a larger reactor than the 40-cubic-centimeter one Pol uses in his lab. But word of the process is quickly spreading: Pol received an e-mail this week from a Los Angeles-based company eager to partner on the technology.

“It is a big benefit,” Pol said. “The plastic is not going to go away.”

WHAT’S UPCYCLING?
The term refers to the process of turning materials with little or no value into something of much greater value. Mike Mitchell, executive director of the Illinois Recycling Association, said examples of upcycling are growing – from leftover glass at glass plants being turned into expensive tabletops to plastic bags being combined with sawdust to create patio furniture.

For those in the recycling industry, Mitchell said, upcycling holds the allure of both environmental and economic benefits.

“When you compare what some products are worth to the cost of collection, the margin gets slim or negative,” he said. “Recycling is a commodity-driven enterprise. … It’s a very foundational environmental issue, but it’s also a huge economic driver.”

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