Scientists Aim for Carbon Neutrality by Making Carbon Nanotubes from Plastic Waste

A research team from the Department of Energy and Chemical Engineering at UNIST has presented an innovative technology for processing plastic waste into carbon nanotubes (CNTs) – a valuable material that plays a key role in achieving carbon neutrality and promoting a circular economy.

Under the leadership of Professor Kwangjin An and Professor Hankwon Lim from the School of Energy and Chemical Engineering and the Graduate School of Carbon Neutrality at UNIST, a joint research team has developed a method to produce carbon nanotubes using mixed gases generated from mask waste. The work was published in Chemical Engineering Journal.

When plastic waste is pyrolyzed, the materials are converted into hydrocarbon gases, including methane, ethylene, and propylene. Scientists harness these gases by treating them at high temperatures to create CNTs.

Carbon nanotubes produced through the upcycling process are environmentally friendly, generating lower carbon dioxide emissions compared to traditional methods based on methane and hydrogen. Interestingly, this approach eliminates the need for a waste separation process, streamlining the procedure.

Using gases produced by thermal decomposition of mask waste, the research team showed that carbon nanotubes can be mass-produced at low cost. Interestingly, the upcycling process works at a cost comparable to existing methods, despite the complexity of the system.

In addition, the research team outlined a carbon neutrality strategy through scenario analyses using renewable energy sources. This study provides the first economic and environmental assessment of carbon nanotube production by recycling plastic waste, revealing a promising route to transforming plastic waste into high-value materials.

First authors Kim Hee-hyang and Nam Eon-woo said: “This process could achieve low-cost production if scaled up and if electricity supply and demand were effectively managed using renewable energy. This would result in significant reductions in carbon dioxide emissions.”

Professors Hankwon Lim and Kwanjin An emphasized: “The increase in the supply of carbon nanotubes thanks to advances in pyrolysis technology will also enhance energy security.”