Potential breakthrough to tackle ‘forever chemicals’ in water

RESEARCHERS are attempting to develop a device capable of degrading a carcinogenic form of the so-called “forever chemicals” PFAS in water in as little as six minutes using low-wavelength ultraviolet light.

PFAS – used in firefighting foam, products such as non-stick pans, and by many industries – repel oil, grease and water, but persist in the environment, resist breakdown, and are typically only filtered and stored, risking recontamination.

Locally, the Australian Defence Force has been working to manage, remediate and monitor PFAS contamination on and around RAAF Base Williamtown since 2018.

The new NSW Smart Sensing Network Grand Challenge Fund project centres on a new Australian National University-developed technology which uses a hydrogen-fuelled plasma to generate vacuum ultraviolet (VUV) radiation.

This low-wavelength radiation triggers photolysis, breaking the strong carbon-fluorine bonds in PFAS and converting them into harmless byproducts like fluoride and carbon compounds – without producing secondary pollutants.

“This technology has the potential to treat large volumes of water simultaneously, much faster than current alternatives, and is another great application of low-pressure plasmas,” Project Co-Investigator Professor Christine Charles said.

“Using this technology, it could take six minutes to treat the same amount of water a conventional radiation source could treat in 10 hours.”

Australian National University (ANU) is building a prototype water-treatment reactor to test the method, which is also highly power-efficient – up to 30 times more efficient than traditional methods.

Researchers say it is also scalable, making it a practical solution for large-scale environmental clean-up and waste-water treatment.

The reactor will feature an integrated in-situ sensing unit designed by University of Sydney researchers, which will monitor the PFAS degradation in real time during treatment.

The project comes after elevated levels of concentrations of PFAS were detected in a Blue Mountains drinking water catchment last year.

It began unexpectedly when PhD researcher Josef Richmond set out to replicate how fine, potentially toxic, and electrostatically charged dust behaves on the Moon, Mars and asteroids.

“In order to replicate these extreme space environments in the lab, I needed to build a radiation source to replicate the high-energy, low-wavelength portion of the solar radiation that is constantly bombarding these bodies in outer space,” Mr Richmond said.

While the original aim was to study a space phenomenon, a student’s remark about its lack of real-world impact led the researcher and Rural Fire Service volunteer to studies on using low-wavelength deep ultraviolet light to destroy PFAS via photolysis.

“The UV sources used in these studies were very inefficient, limiting the effectiveness of the treatment process,” Mr Richmond said.

“After some investigation, it turns out that the radiation source we had developed was significantly more efficient and could potentially remove this barrier to scaling up to levels that are useful in the real world.”