How can we spur plastic upcycling? Turn it into Graphene

2024-09-14

In a groundbreaking development, Australian scientists have devised a method to convert harmful microplastics into valuable graphene, offering a promising solution to plastic pollution. Graphene, a material consisting of a single layer of carbon atoms, exhibits unique properties that make it highly sought after in electronics, biomedical technology, and solar panels.

Microplastics are now recognized as a significant environmental and health hazard due to their ubiquitous presence. In response to this issue, a team led by Mohan Jacob, a professor of electrical engineering at James Cook University, has utilized an advanced technology known as atmospheric pressure microwave plasma to address both plastic waste and material production.

Jacob and his team have adapted this technology, previously used to synthesize graphene from gases like methane and ethanol, to process microplastics. Atmospheric pressure microwave plasma involves channeling microwaves into a chamber filled with gases such as argon, creating a highly reactive plasma state. This plasma breaks down the microplastics into gases like methane, which then decomposes further in the plasma to release carbon atoms. These carbon atoms eventually reorganize into the hexagonal lattice structure of graphene.

Compared to traditional graphene production methods, such as Chemical Vapor Deposition (CVD), this approach is more environmentally friendly and cost-effective. "Atmospheric pressure microwave plasma not only produces high-quality graphene but also eliminates harmful microplastics from the environment," explained Mohammed Adeel Zafar, a researcher at James Cook University and co-author of the study. This dual benefit aligns with sustainability goals and supports a circular economy.

In their recent experiments published in *Small Science*, Jacob's team achieved a six-to-one conversion ratio, meaning that 30 mg of microplastics yielded 5 mg of graphene. The quality of the graphene produced matched or even exceeded that from conventional sources, making it suitable for various commercial applications including electronics, energy storage, composite materials, and environmental technologies.

However, the technology faces challenges related to scalability. Currently, the process is less effective for plastics containing high levels of additives, fillers, or contaminants. Additionally, plastics with chlorine, such as polyvinyl chloride (PVC), can produce toxic by-products, raising safety and environmental concerns. Jacob's team is working on optimizing the process to handle a broader range of microplastics and exploring larger reaction chambers to make the technology viable for industrial-scale applications.

These advancements represent a significant step toward mitigating plastic pollution and advancing sustainable material production. As research progresses, atmospheric pressure microwave plasma could become a crucial tool in upcycling plastic waste and promoting a more sustainable future.