Researchers from RMIT University in Melbourne, Australia, have discovered a method to convert plastics into carbon nanotubes and a clean liquid fuel.
In addition, they use agricultural and organic waste to turn these plastics into new high value products.
Carbon nanotubes are hollow, cylindrical structures that have exceptional electronic and mechanical properties. They are used in hydrogen storage, composite materials, electronics, fuel cells and biomedical technologies. In particular, there is growing demand for them from the aerospace and defence sectors.
The process to turn these waste plastics into carbon nanotubes and liquid fuels involves turning agricultural and organic waste into biochar. This biochar is used to remove toxic contaminants from the plastic as it is broken down into its components of gas and oil.
At the same time, the carbon in the plastic is converted into the carbon nanotubes, which coat the biochar.
These nanotubes can be exfoliated for use by industry or the nano-enhanced biochar can be used directly for environmental remediation and boosting agricultural soils.
RMIT University associate professor Kalpit Shah said: “We focused on polypropylene as this is widely used in the packaging industry. While we need to do further research to test different plastics, as the quality of the fuel produced will vary, the method we’ve developed is generally suitable for upcycling any polymers.”
The experimental study conducted at lab scale can also be replicated in a new type of hyper-efficient reactor that has been developed and patented by RMIT.
It uses fluidised bed technology and offers significant improvement in heat and mass transfer, to reduce overall capital and operating costs.
The next steps involves detailed computer modelling to optimise the technology and pilot trials in the recycling sector. Researchers from RMIT are keen to work with plastic producers and recyclers to further develop the technology.