Researchers at Monash University have developed a new membrane technology that could make chemical recycling of plastics cheaper, cleaner and more efficient by improving the recovery of valuable chemicals used in the process.
Developed in collaboration with CSIRO and The University of Texas, the breakthrough focuses on improving glycolysis – a recycling method used to break down PET plastics such as drink bottles, food packaging and synthetic textiles.
The study, published in the Chemical Engineering Journal, outlines how specially designed nanocomposite membranes can separate water from ethylene glycol, a chemical used in the recycling process that is difficult and costly to recover using traditional methods.
Rather than relying on energy-intensive recovery systems, the membranes act as highly selective filters, allowing ethylene glycol to be recovered at high purity and reused during depolymerisation.
Researchers say the development could lower chemical use, improve recycling economics and support efforts to create a more circular plastics industry.
Lead author Dr Hamidreza Mahdavi, a research fellow at the Monash Department of Materials Science and Engineering, said the work addressed a significant challenge in existing recycling systems.
“Plastic waste still contains valuable building blocks. Our work shows that membrane technology can help recover these building blocks more efficiently from PET recycling streams, so they can be reused rather than wasted,” Dr Mahdavi said.
“Instead of only recovering energy from end-of-life plastics, we are trying to recover the building blocks needed to make new materials. This is an important step toward a more circular approach to plastic recycling.”
During glycolysis, PET plastics are chemically broken down into reusable raw materials. However, the process has historically faced commercial barriers because recovering ethylene glycol from the reaction mixture can be expensive and energy intensive.
The research team said the membrane-based separation system demonstrated strong performance under conditions relevant to real-world industrial recycling processes, providing a practical pathway for future commercial scale-up.
Researchers believe the innovation has the potential to reduce landfill waste and emissions while helping improve the viability of advanced recycling technologies.
The work builds on a broader Monash and CSIRO research program examining membrane-based recycling technologies. Earlier studies identified membrane systems as a promising approach for chemical recycling, while the latest experimental research demonstrates the concept in practice.
The project was conducted under the CSIRO-Monash collaboration program, with further research already planned to advance the technology and explore future industrial applications.