West Virginia University advances polypropylene recycling technology

USA – Researchers at West Virginia University (WVU) are developing an innovative method to recycle polypropylene (PP), a plastic widely used in packaging, using microwave technology.

Spearheaded by chemical engineer Yuxin Wang, the technique aims to recover propylene, a key chemical compound in PP, through a more energy-efficient process.

This method offers two significant advantages: precise heating control and operation at much lower temperatures—around 300°C compared to the traditional 600°C to 700°C.

Instead of conventional recycling, where plastics are broken down into reusable pieces, this approach breaks PP back into its fundamental chemical components.

These can then be repurposed for various applications beyond just recreating the original product.

The technique involves heating a catalyst with microwaves, transferring heat to the PP waste, and breaking it down into its original chemicals.

This upcycling method goes beyond standard recycling, creating valuable chemicals that can be used in various manufacturing processes.

The research has been supported by a US$1 million grant from the US Department of Energy (DOE). Wang explained the broader implications, “Traditional recycling limits reuse to the same product. Our method generates chemicals that can make polypropylene again and be valuable for other reactions.”

This project also creates educational opportunities for WVU students, who will gain hands-on experience at the Advanced Photon Source (APS) facility at Argonne National Laboratory in Illinois.

Students will collaborate with Tao Li from Northern Illinois University, an expert in catalytic reaction processes, learning cutting-edge plastic upcycling techniques.

Wang emphasized the educational benefits, “WVU students will use new techniques developed at APS to explore plastic upcycling mechanisms, helping to address our plastic waste issue.”

In parallel, researchers at the University of California, Berkeley, recently developed a chemical process that “vaporizes” polyethylene, polypropylene, and mixed plastic waste into building blocks for repolymerization.

According to the researchers, ff scaled, this process could reduce the reliance on fossil fuels and promote a circular economy for single-use plastics.

Globally, around two-thirds of post-consumer plastic is made from polyethene and polypropylene, with approximately 80% ending up in landfills, incineration, or polluting natural environments.

UC Berkeley’s efforts, led by chemistry professor John Hartwig, focus on breaking down the stable carbon-carbon bonds in polyolefins, such as those found in plastic bags and bottles, and converting them into reusable monomers. This advancement brings the goal of true circularity for plastics closer to reality.

Employing solid catalysts, which can be reused in continuous flow processes, has also addressed the challenge of recovering catalysts used in earlier processes, making the approach scalable for industrial applications.

This breakthrough promises to unlock new potential for large-scale recycling of currently downcycled or discarded plastics.

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