Researchers have made a significant breakthrough in the fight against per-and poly-fluoroalkyl substances (PFAS), commonly referred to as 'forever chemicals'. 

These chemicals, known for their resistance to degradation, are pervasive in various consumer products and have contaminated water sources globally.

A team at the University of New South Wales (UNSW) Sydney, led by Dr Jun Sun and Professor Naresh Kumar from the School of Chemistry, has engineered a catalyst system capable of initiating a reaction to decompose branched PFAS compounds. 

This innovative method, detailed in a recent publication in Water Research, promises a more effective and sustainable solution for PFAS remediation.

“Owing to its robust nature, simple application, and cost effectiveness, the new system we have developed shows successful PFAS remediation in the lab, which we hope to eventually test at a larger scale,” Dr Sun says.

PFAS, used in a variety of products such as non-stick cookware, firefighting foams, and cosmetics, are highly durable due to their stable chemical structure. This durability has led to widespread environmental contamination. 

Reports indicate that many water sources exceed safe drinking limits for PFAS, raising significant health and environmental concerns. 

Some PFAS types, like perfluorooctanoic acid (PFOA), have been linked to adverse health outcomes, including cancer, as recognised by the World Health Organization.

Existing methods for PFAS removal, such as absorption onto activated carbon, are inefficient and environmentally taxing. 

“So if you’ve got a pad of activated carbon, and you pass water through it, you can absorb PFAS onto the activated carbon, but you then have to burn it to destroy the PFAS, or safely store it,” says researcher Professor Naresh Kumar.

This process, while isolating PFAS, does not eliminate the chemical, leading to further waste management challenges.

The new method involves a catalyst system using nano zero-valent metals (nZVMs) and a porphyrin ring structure, inspired by vitamin B12, which has shown potential in catalysing similar reactions. 

Testing on branched PFOS and PFOA revealed that this system could achieve approximately 75 per cent degradation within five hours, significantly outperforming existing catalysts.

The UNSW team aims to scale up this method for real-world applications. 

“The next step for us is to really try this on a pilot scale to see if this can be done out of the laboratory on a real sample,” Professor Kumar said.

There are plans to integrate the catalyst into an electrode for use in electrochemical cells, potentially allowing for more widespread and efficient PFAS degradation.

The development is a result of collaborative efforts involving Prof Denis O’Carroll, Prof Michael Manefield, and Dr Matthew Lee from the UNSW School of Civil and Environmental Engineering. 

The research was supported by a $3 million grant from the Australian Research Council awarded in 2019.