Research led by James Cook University has explored the potential of microwave-assisted pyrolysis as a method for converting waste streams such as tyres, plastics and fibres into fuels and advanced carbon-based materials
The study, published in the Journal of Analytical and Applied Pyrolysis, highlights how the technology could support more efficient waste processing while creating value-added outputs including building materials, electronics and anti-fouling products.
While pyrolysis itself is a long-established process, microwave-assisted pyrolysis represents a variation that uses microwave energy to heat materials more rapidly and controllably. “Pyrolysis is not a new technology at all … humans have been using it for a long time,” said Mohan Jacob, lead researcher on the project. “But in a modern twist, we are using microwave energy, which can rapidly and controllably heat the material. Our research focuses on how we can use this technology to better manage our current waste problems.”
Pyrolysis involves heating carbon-based materials in the absence of oxygen, producing char, oil and gas. According to the research team, microwave-assisted pyrolysis can significantly reduce processing times compared with conventional systems. “The energy efficiency for microwave heating is really good. The conventional process might take 24 hours to fully process, but with microwave heating, we can achieve the same thing in one hour, and we can completely use renewable energy for that,” Prof Jacob said.
The research from James Cook University also points to operational and logistical advantages, particularly for decentralised waste management. “These systems can be customised for use across a wide range of industries and businesses,” he said. “A key advantage is the ability to transform most waste materials directly on-site, with minimal or no pre-processing, leading to reduced transportation costs and lower environmental impacts.” He added that the process can reduce waste volume significantly, noting that “microwave pyrolysis can reduce the volume of the original waste by 95% for plastics, or 60% less for tyres. At the same time, the waste can be turned into value-added products.”
The resulting char can be used in a range of applications depending on its quality. “If the char is low quality, you can use it as a soil supplement, enhancing plant growth and helping to sequester carbon from the atmosphere,” Prof Jacob explained. “Alternatively, we can refine the char again and produce higher value materials such as activated carbon and graphene, which have applications in composite materials for batteries, electronic sensors or antifouling surfaces.”
Although microwave-assisted pyrolysis is still developing, pilot and demonstration projects are already underway internationally. In Canada, Environmental Waste International has been advancing microwave-based tyre recycling systems, while in Europe, the SULFREE project has explored related pyrolysis approaches to improve resource recovery and reduce environmental impacts. These initiatives reflect growing interest in alternative thermal technologies as part of broader efforts to transition towards more circular waste management systems.
Image credit: James Cook University
