News: News, Research

Microcapsules trap persistent PFAS contamination

Per- and polyfluoroalkyl substances (PFAS) are a group of toxic chemicals that have been manufactured and used globally in a variety of industries since the1940’s.

They are very persistent and do not break down and have been found in everything from drinking water to agricultural land. Once consumed they accumulate within the body and can cause adverse health effects. Being able to capture and eliminate PFASs from the environment is therefore very important.

Published in Environmental Science & Technology, A/Prof. Rico Tabor’s research at Monash University focuses on a new method they developed to capture PFAS detergents (the most mobile and troublesome form of the contamination) using tiny carbon-coated capsules filled with olive oil. The capsules have a diameter around one-fiftieth that of a human hair, allowing them to penetrate soils and follow water percolation pathways.

Scanning (SEM) and transmission electron microscopy (TEM) at our facilities at Monash University – the Monash Centre for Electron Microscopy – were used to characterise capsule morphology. SEM images of the dried shell showed the spherical shape, rough surface, and the hollow structure of the microcapsules. TEM was then used to further examine this morphology revealing cracks on the surface providing evidence of the capsules being hollow.

A. Scanning electron micrograph of the microcapsule. B & C. Transmission electron micrographs of the microcapsules.

 

“Contamination from PFASs is a threat to the environment,” said Associate Professor Rico Tabor.

“Their accumulation in water and soil means that they are being detected in agricultural land, water treatment facilities and even drinking water sources,” he said.

“Particularly worrying are detergent forms of these substances, as they can easily move between soil, sediment and water, ending up almost everywhere. For the first time, we show that microcapsules can be used to capture mobile PFAS contamination. The capsules work almost like synthetic microbes, ‘eating’ contaminants and retaining them inside.”

Melbourne’s $6.7bn Westgate Tunnel is currently at a standstill following the detection of PFASs in soil removed during excavation at the site.

“It is clear that methods for decontaminating PFASs from soil and water are urgently needed,” A/Prof. Tabor said.