Young researcher makes reusable PFAS remover

Removing forever chemicals like PFAS out of our waterways is an ongoing research question. Cheng Zhang, a researcher at the University of Queensland, has created a reusable PFAS remover.

Per- and polyfluoroalkyl substances (PFAS) have become a problem in water across the world. Numerous research teams are taking different approaches to remove it from the water. Some PFAS are effective at resisting heat, stains, grease, and water, making them useful chemicals for various applications. These applications include stain and water protection, photographic materials, cosmetics, and sunscreen. Because they are heat resistant and film-forming in water, some PFAS have also been used as effective ingredients in fire-fighting foams.

In Australia, the historical use of PFAS in fire-fighting foams has resulted in increased levels being detected at airports, defence bases, and other places where firefighting training has been conducted. Increased environmental levels of PFAS have also been found in some industrial areas, effluent outfalls, and landfill sites.

The greatest concern of PFAS is highly mobile in water. It does not fully break down naturally in the environment and is toxic to many animals. While understanding the human health effects of long-term PFAS exposure is still developing, there is global concern about these chemicals in the environment.

Dr Cheng Zhang is making a difference

Dr Cheng Zhang from the University of Queensland (UQ) is one of those researchers investigating a new way to remove PFAS from water. His paper on the topic was published in October in the high-profile Angewandte Chemie International Edition. The paper was titled “Efficient Removal of Perfluorinated Chemicals from Contaminated Water Sources Using Magnetic Fluorinated Polymer Sorbents.”

Originally from Shandong in China, he has lived in Australia for more than ten years. He has enjoyed the research environment at UQ, as well as the living environment in Australia. As a National Health and Medical Research Council (NHMRC) CJ Martin Research Fellow (2019-2022) and the recipient of a Discovery Early Career Researcher Award (2023-2025), Zhang is working hard to make a difference.

“I am a polymer chemist, by my research. I only started studying water management in the last two or three years. However, it is how I started focusing on PFAS,” said Zhang. “Having said that, I have been studying this style of fluoropolymers for over ten years.”

Zhang started his academic life in materials science. His studies in this field got him into studying real-world problems with real-world solutions. The opportunity to remove contaminants from water, such as PFAS, attracted him to move sideways from materials science to polymer chemistry.

What his research has found

Zhang and his team focused on developing a PFAS remover by capturing PFAS efficiently and selectively. Each PFAS molecule has a hydrophilic “head” and a long, hydrophobic “tail” that contains carbon-fluorine bonds. The carbon-fluorine bond is one of the strongest single bonds in nature. That bond gives the molecules persistence in the environment and their “forever” moniker. Legacy PFOA and PFOS, as well as emerging GenX, which are the focus of most water treatment efforts, can persist in the environment and may pose harm.

On that basis, Zhang started investigating the capture of PFAS using a unique polymer sorbent. His research found that their now-patented polymer is a reusable PFAS remover. It is also efficient and selective.

“The efficient treatment of PFAS-contaminated water is becoming an essential consideration for establishing water sustainability in Australia,” Zhang said. “Our product addresses the issue of extensive PFAS pollution in Australia and will deliver ongoing benefits to the Australian water and environmental industries and local communities.”

Industry collaboration

His masters and PhD students are working together to advance the technology. They believe in the importance of collaborating with industry partners.

“Industry partners have been very interested in the technology. Our polymer has a very high capacity and a low cost, especially considering it can be reused multiple times. Compared to any other substance, it is over ten times more efficient than activated carbon,” said Zhang. “That’s a massive advantage of our technology. It is also an area of research that we are targeting – increasing capacity, improving selectivity, and reducing cost.”

One industry partner that has been heavily involved in the research is the industrial corporation Chemours, a spin-off company from Dupont. As the producer of Teflon, Nafion membranes, Krytox lubricants, and Opteon refrigerants, they produce a significant amount of PFAS.

“One possibility is that they can develop a large-scale production facility, given their manufacturing lines in the United States. Chemours has supported us a lot over the last two to three years, and we have a good relationship with them. We have also secured funding from the US Department of Defence and The University of Queensland’s Knowledge Exchange and Translation (Kx&T) ECR Funding. Hopefully, we will be able to use their production lines,” said Zhang. “Once we optimise the materials production procedures, I think they will be happy to move forward on that, as we should be able to generate plenty of revenue.”

Difference between technologies in PFAS remover

There have been several different techniques looking at methods of capturing PFAS. Activated carbon is the most commonly used technology and has been broadly used as a PFAS remover. However, the carbon sorbent has low efficiency, is non-selective, and is non-reusable.

Zhang acknowledged this and other research occurring over the past couple of years. He pointed out that one of the biggest issues for most research teams in this field is that they must operate with concentrated levels of PFAS.

“In the real world, levels of PFAS concentration tend to be very low and even much lower than the nonfluorinated organic and inorganic species. The advantage of the polymer we have developed is that it can selectively and specifically recognise and grab PFAS. It makes things a lot easier and more realistic. Because our technology focuses on low concentrations of PFAS, the polymer can grab onto more of it,” said Zhang.

He also acknowledged that different techniques could work together to maximise the efficiency of PFAS removers. The opportunity to solve a real problem inspires Zhang.

“I think that I am lucky to have identified this real problem and focused on the root cause of the contamination in the environment. Being able to work in related fields where I am creating new materials that solve real societal problems,” said Zhang.

Communication skills

Another area that Zhang is noted for is his experience in communicating his scientific achievements to a broad audience. As a young researcher that collaborates with industry, he has had to learn how to use non-technical language to explain his project.

“Taking part in Fresh Science was an excellent experience,” he said. “At one point, I needed to explain my research in 100 words or less. That was a challenging experience but revising my language so that industry partners could understand was fantastic. The willingness to understand the different backgrounds of my audience helped enormously. All the training and competitions were great at helping me understand what I was saying and how to express my research to a broad audience.”

Moving from the focus of publishing papers to communicating with a wider audience is an important skill. Zhang acknowledged that he would continue to develop this skill as he grows as an individual and a researcher. He is also a material scientist working in energy storage and medical fields.

“I’m trying to find partners to collaborate with in those two fields. Fortunately, I now have experience from my time studying PFAS. That has given me a good base of knowledge to explain my scientific research and how my research career can help industrial partners,” he said.