In a shift away from simply burning or burying waste, new research led by James Cook University recommends using microwave energy to transform waste into high-value building materials, electronics and anti-fouling products.
Research published in the Journal of Analytical and Applied Pyrolysis has reviewed the potential for microwave assisted pyrolysis (MAP) to convert problematic waste materials such as tyres, plastics and fibre, into fuels and high-end carbon materials.
"Pyrolysis is not a new technology at all … humans have been using it for a long time." said the lead researcher and one of the paper's authors, JCU Professor Mohan Jacob.
"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 a carbon-based material in the absence of oxygen, breaking it down into solid char, combustible oil and combustible gas.
"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.
Image: Prof Jacob (R) and his team of MAP researchers (L to R) Muliyana Arifudin, Gopika Kaimal and Dr Saeed Moarrefi, in front of their pyrolysis equipment.
Prof Jacob suggested MAP could be used to reduce the costs of waste management for industry and councils.
"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.
"For example, microwave pyrolysis can reduce the volume of the original waste by 95 percent for plastics, or 60 percent less for tyres. At the same time the waste can be turned into value-added products."
The research paper outlines how the char that is produced using MAP can have a variety of potential uses and benefits.
"If the char is low quality, you can use as a soil supplement, enhancing plant growth and helping to sequester carbon from the atmosphere," said Prof Jacob.
"Alternatively, we can refine the char again and produce higher value materials such as activated carbon and graphene, which has applications in composite materials for batteries, electronic sensors or antifouling surfaces."
Prof Jacob said our priority should be on converting waste into highly useful and valuable products.
"MAP has the potential to help us move to a more circular economy, reducing environmental impacts," he said.
