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IBM’s VolCat process uses ‘molecular sorting’ to turn mixed-waste recyclate into virgin-grade PET

IBM Volcat recycling
The catalytic recycling process selectively finds polyester material in the witches’ brew of waste material and repolymerizes it into new PET, said IBM.

More than 272 million metric tons of plastic are produced each year around the globe, most of which ends up in landfills and waterways. One-quarter of that is made up of PET, a plastic commonly used in food and beverage packaging such as water bottles (bearing the #1 recycling label) and polyester clothing.

To combat this problem, IBM researchers recently created a technology called VolCat, a catalytic chemical process that can turn PET into a renewable resource. The cost-effective and sustainable innovation “digests” PET using a precise combination of chemicals, heat and pressure.          

Bob Allen, a chemistry and materials researcher for IBM who specializes in polymer materials with expertise in catalysts, told PlasticsToday that the new process that he helped to develop is akin to the depolymerization process that some companies are currently offering. “Depolymerization has been around for a long time. Among the questions that have to be answered: Is it economical and how robust is the process?” said Allen.

“What makes our process a little different is that we perform catalytic recycling, which is extremely selective in seeking out and finding polyester material in the witches’ brew of waste material. The polyester content is then repolymerized into new PET. Because there are two molecules of ethylene glycol attached to it, it can make new PET very easily.”

Allen noted that preliminary testing shows that value can be created by making new batches of PET from “very challenging mixed waste” materials. IBM’s process reportedly creates new PET that is indistinguishable from virgin PET. “Once the process is finished, because our catalyst is a volatile compound and the catalyst goes away from the reaction mixture, we recover and recycle all the catalyst,” he said. “There’s no waste involved in the VolCat catalytic process.”

The most innovative aspect of the VolCat process is that it eliminates the need for manual sorting because “the molecule does the sorting,” Allen explained.

Allen said that the VolCat process can reduce the amount of plastic being sent to landfills because it addresses the concerns of processors regarding contamination. “PET waste from a recycling plant might contain 90% PET, but regardless of how high quality the recycling stream is, they can’t take colored PET bottles. There’s not a lot that can be done with colored PET,” explained Allen. “Using the VolCat molecular sorting process, selective digestion just chews up the polyester component and makes new PET with the same properties as virgin PET. Foreign matter from municipal curbside collection that contains dirt, labels and adhesives—just chuck it all in and let VolCat run amok on the polyester to isolate the pure monomer from that mess and make new PET. This unbelievable catalyst is completely recoverable and completely ignores all this other material.”

Currently, VolCat is still in IBM’s laboratory and has not yet been commercialized. However, said Allen, “pilot discussions” are underway with several companies.

“Innovation is really required to move the industry from where we are today to something that takes advantage of this waste as a natural resource,” Allen concluded. “We feel strongly that material and process innovation is key to helping the world with the waste plastic issue. We want to move the VolCat process out of the lab and into the world as quickly as we can.”

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