Researchers make PFAS breakthrough

07062019

The Australian Defence Magazine

The problem of cleaning up toxic polyfluorinated alkyl substances (PFAS) pollution has seen a breakthrough in the discovery of a new low-cost, safe and environmentally friendly method that removes PFAS from water.

PFAS pollution does not break down readily in the environment and was extensively used in fire-fighting foams at airports and Defence sites, resulting in contaminated ground and surface water.

Researchers from the Flinders University Institute for NanoScale Science and Technology, in collaboration with the University of SA, have developed a new type of absorbent polymer made from waste cooking oil and sulfur combined with powdered activated carbon (PAC).

While there have been few economic solutions for removing PFAS from contaminated water, the new polymer adheres to carbon in a way that prevents caking during water filtration. It works faster at PFAS uptake than the commonly used and more expensive granular activated carbon method, and it dramatically lowers the amount of dust generated during handling PAC that lowers respiratory risks faced by clean-up workers.

“We need safe, low-cost and versatile methods for removing PFAS from water, and our polymer-carbon blend is a promising step in this direction,” Flinders University’s Dr Justin Chalker, co-director of the study, said. “The next stage for us is to test this sorbent on a commercial scale and demonstrate its ability to purify thousands of litres of water. We are also investigating methods to recycle the sorbent and destroy the PFAS.”

During the testing phase, the research team was able to directly observe the self-assembly of PFOA hemi-micelles on the surface of the polymer. “This is an important fundamental discovery about how PFOA interacts with surfaces,” Dr Chalker explained.

The team demonstrated the effectiveness of the polymer-carbon blend by purifying a sample of surface water obtained near a RAAF base. The new filter material reduced the PFAS content of this water from 150 parts per trillion (ppt) to less than 23 ppt, which is well below the 70 ppt guidance values for PFAS limits in drinking water issues by the Department of Health.

The core technology for this PFAS sorbent is protected by a provisional patent. 

“Our canola oil polysulfide was found to be highly effective as a support material for powdered activated carbon, enhancing its efficiency and prospects for implementation,” Nicholas Lundquist, PhD candidate at Flinders University and first author in the ground-breaking study, said.

The project was a collaboration funded by the SA Defence Innovation Partnership, with further support from industry partners Puratap and the Salisbury Council. Co-directors of the study were A/Prof Sally Plush and Prof John Hayball at UniSA and Dr Justin Chalker at Flinders University.

Flinders PhD student Nicholas Lundquist was the lead author of the study in collaboration with Research Fellow Dr Martin Sweetman of UniSA.

Other key contributors to the study were several current and former members of The Flinders University Institute for NanoScale Science and technology including Kymberley Scroggie, Max Worthington, Dr Louisa Esdaile, and Salah Alboaiji.