Microplastics, nanoplastics and per- and polyfluoroalkyl substances (PFAS) are increasingly recognised as persistent contaminants in the environment and water systems. While conventional water treatment technologies can remove some pollutants, tackling these chemically and physically distinct contaminants simultaneously remains a significant scientific and technological challenge worldwide.
A dedicated team of researchers at RMIT University in Melbourne, Australia, led by Dr Mohammad Haris, has been working on a promising approach to address this challenge. Dr Haris is part of the Innovative Resources and Waste Technologies (iRWT) research group. The team has developed a technology that can remove microplastics, nanoplastics, and PFAS from contaminated water. This research goes beyond conventional filtration, exploring new ways to capture and eliminate pollutants that are difficult to detect and remove with existing traditional treatment methods.
In this interview with our team member Hadia Rashid, Dr Haris discusses the science behind the technology, why microplastics, nanoplastics, and PFAS are particularly challenging contaminants, and how this teamwork can contribute to more effective water purification.
Watch on YouTube: Beyond Filtration: The Breakthrough That Could Clean Our Water with Dr Haris at RMIT, Australia
Hadia Rashid: Your team is working on the simultaneous removal of microplastics, nanoplastics, and PFAS. These are quite different types of pollutants. So what inspired your team to bring them together in one treatment approach?
Dr. Muhammad Haris: It’s an excellent question. When we talk about pollutants, they fall into different categories, and the ones I’m referring to are usually classified as emerging pollutants. So we can talk about microplastics, PFAS, and microfibers differently—these are also top pollutants in different research.
But when we see them in the natural environment, they usually coexist. So we started this work in early 2022 with microplastics, and then, because, as I said, they coexist in the natural environment, and PFAS is a very problematic pollutant as well and has very strict regulations around the world. So we thought that there should be a platform where we can address multiple pollutants at a time rather than addressing them separately.
Hadia Rashid: For someone hearing about PFAS for the first time, could you briefly explain what PFAS are and why they are often referred to as forever chemicals?
Dr. Muhammad Haris: PFAS are basically fluorocarbons. It’s a class of fluorocarbons with a carbon-fluorine bond, which is considered one of the strongest bonds in chemistry. They break down very slowly in the natural environment, and they have been widely used because of their exceptional stability. This property also creates a problem: they don’t break down; this is why they are called chemicals forever. And once they enter the human body, they are going to stay there forever and can cause several severe diseases. PFAS is not composed of only one class of fluorocarbons. Basically, it represents a very large group of fluorocarbons.
Hadia Rashid: Your team has reportedly demonstrated more than 95% removal of micro- and nanoplastics within an hour. Could you walk us through what actually happens when this magnetic adsorbent comes into contact with contaminated water?
Dr. Muhammad Haris: Once we talk about microplastics and nanoplastics, one thing is, just for the sake of understanding, a human hair is around thousands of nanometers in size. So when we talk about nanoparticles, we basically can’t see them, and they can be in different sources of water. When we go below the size of microplastics, they become very hard to remove from water. Usually, these particles are forced through the membranes to be removed. But it is very problematic for the smaller sizes because they usually escape through the compact membranes or the pores- these sorts of issues.
When we tested under different circumstances and conditions, we showed that it can remove up to 90%. The main thing is, rather than just removing 30 nanometers, we created a platform where we absorb those small nanoparticles onto magnetic material. We also removed larger particles, not just 30 nanometers. Since we used magnetic materials, we are looking beyond filtration. Our idea is to regenerate it, reuse it multiple times, and then convert it back into another functional material once it reaches the end of its life. Once the nanoparticles attach, we use an external magnet that pulls out the material, which already has the pollutant loaded on top of it. So yes, it is reusable.
In the lab, we have shown up to five cycles where we can reuse the same material multiple times. So we can regenerate it and reuse it.
Hadia Rashid: So that powder is made from waste?
Dr. Muhammad Haris: We started from waste, but then to make it more commercially viable, we now use a common carbon source. But you are right; we start with the waste, but it can work with several carbon precursors. And this is undoubtedly the beauty of our platform: we can tweak the properties and raw materials as required
Currently, it is not waste. It is a commercially available carbon material; our main idea was to convert it into real-world usage. We were thinking about how we can develop this platform so it’s easy to use and can be synthesized at commercial scale beyond the laboratory.
Read more from the author: A Legacy of Discovery: James Watson, Co-Architect of the DNA Double Helix, Passes at 97
Hadia Rashid is a BS (Hons.) student of Applied Microbiology at UVAS Lahore. Passionate about science communication, she writes to bridge the gap between research, the environment, and society.
