Chemical engineers at the University of New South Wales (UNSW) have developed a groundbreaking method to break down tough polymers into reusable raw materials using just sunlight, air, and a common chemical compound.
This innovative process could advance plastic waste management by providing a low-energy, sustainable solution for recycling a wide range of plastics.
The research team, led by Professor Cyrille Boyer from the School of Chemical Engineering, has demonstrated that their method can effectively degrade polymers such as polystyrene, polyvinyl chloride (PVC), and poly (ethylene glycol), which are commonly found in various household and industrial products.
The process, which operates at room temperature, uses iron trichloride–also known as ferric chloride – a cheap and widely available compound, combined with light and oxygen to break down the plastics.
In experiments, the team achieved a 90 per cent breakdown of seven distinctive types of polymers in less than 30 minutes, with the degradation increasing to 97 per cent after three hours.
Their findings were recently published in Macromolecular Rapid Communications.
Dr. Maxime Michelas, a researcher in Professor Boyer’s group, highlighted the significance of this innovation.
“It’s very important to degrade the polymer and turn it into another feedstock we can use for other things, or just to reduce the amount of microplastics in the world,”said Michelas.
The process begins with dissolving the polymer in a solvent.
When the solution is exposed to ferric chloride and light, it quickly breaks down, eventually becoming clear.
The researchers initially used dim, purple light in a controlled environment, but found that sunlight and ambient air also worked, but at a slower pace.
The simplicity of this system is one of its key strengths, according to Dr. Michelas.
Unlike previous methods that required complex setups involving electrodes and multiple co-catalysts, UNSW’s approach is straightforward and versatile, capable of degrading a broader range of polymers.
Despite its promise, the method has some limitations.
The use of organic solvents, which are not environmentally friendly, and the inability to precisely control the byproducts of the degradation process are challenges the team is working to overcome.
Professor Boyer’s team is currently exploring new catalysts that could operate in water, which would be a major environmental advancement.
The importance of such research is highlighted by the growing global plastic waste crisis.
In Australia alone, plastic consumption has more than doubled since 2000, and it is expected to double again by 2049.
Dr. Michelas pointed to the Great Pacific Garbage Patch, a massive collection of ocean plastic twice the size of Texas, as a stark reminder of the urgent need for innovative solutions.
Professor Boyer’s team remains committed to refining their method, with the goal of developing a process that could degrade polymers without the use of solvents, potentially transforming plastic waste management worldwide.