Meet the Teenager Who Figured Out How to Remove Microplastics From Water


There’s clever people and then there’s just flat out geniuses, and Fionn Ferreira sits firmly in the latter category.

At just 18-years-old, Fionn did what scientists triple his age have tried and failed to do: he figured a way to remove microplastics from water. If microplastics sound vaguely familiar, it might be because you’ve been ingesting tens of thousands of them every year. They’re tiny pieces of plastic less than 5mm in length that exist in our waterways and even the air, and make their way into the food we eat and the water we drink. So, no good. But that’s where Fionn comes in. His lightbulb moment came when he was kayaking near his home in a remote region of Ireland, and he spotted a rock coated in oil from a recent spill that had small pieces of plastic stuck all over it. Almost a thousand test experiments later, Fionn discovered a non-harmful way to extract these microplastics from water using a kind of magnetic liquid made from vegetable oil and rust powder. Put simply, his discovery will more than likely be a game-changer for our oceans and waterways. When I dialled into the teenage prodigy’s new digs in the Netherlands, he was coming off the back of his usual eight-hour stint in the chemistry lab and I was just coming off the couch after four-straight hours of my favourite spy show. The world needs all kinds, I guess.

Hey Fionn! So, you’re studying in the Netherlands at the moment?

Groningen, in the very north. We’ve got a really big chemistry department here so it’s great. Today I had eight hours of lab work; we do that every day.

And you’re originally from West Cork in Ireland. What was it like growing up there? 

Growing up in West Cork was really wonderful because I was able to be outside all the time… when the weather was good. I didn’t have a games console or play computer games, pretty much everything I did was outside. Also just living by the coast, there’s so many water sports and activities you can do. For me, it was kayaking, sailing and swimming. I think being so close to the coastline really brought a sense of love for the coastline and when I would see pollution on it, that would really resonate with me.

And were you always just tinkering away at experiments growing up? Were your parents involved in the sciences too?

No, my parents aren’t involved in the sciences. My father builds wooden boats and my mother paints and does souvenir models that people can build themselves out of paper. I think what really helped me there was that they both had quite a lot of experience in building and modelling and that made me naturally want to do stuff with my hands. I was building little devices that could help me clean up the seashore or measure things about the seashore—artificial-based intelligence devices where I could take a picture of the seashore and it could find plastics in it. Any kind of technologies to do with the shoreline and the environment I loved. Almost all of them didn’t work, but I thought that was a really nice process; trying something out and realising it doesn’t work, and you learn from your mistake. Well, I don’t call them mistakes, but the way you found out it doesn’t work and then improve for the next one.

And in your own words, can you explain how you discovered that magical combination of elements that made extracting the plastic from the water possible? 

Yeah, so they were all things that I was independently experimenting with and didn’t expect to come together. I saw a video on YouTube about ferrofluids and how cool they are when you bring a magnet close to them. I thought, ‘that’s cool, I have to make some ferrofluids.’ I got some old cassette tapes from our local second-hand store and scratched the iron—there’s like an iron powder on the cassette tapes—so I scratched that off and dissolved that in oil and made a huge mess. I still remember there was black and brown stuff everywhere. But I had a little bit of ferrofluid; it was this oily black liquid. At the same time, I was working on ways to identify microplastics in water, so I was trying to use these things called spectrometers.

And what do spectrometers do?

They basically shine light through a sample of water and analyse the light to measure plastics in water. That worked pretty well, but in a bid to try and get rid of the bubbles in one of these little vials inside the machine, I thought, maybe I’ll just try to put some vegetable oil on top to get rid of the bubbles of air. Then all the plastics got stuck to the vegetable oil and I it seemed to be attracting the plastics. I thought, vegetable oil is very close to ferrofluid, so I tried the three out together and it seemed to work extraordinary well.

Was part of you like, microplastics are such a massive problem, how has no one thought to do this yet?

Yeah, when I started on this work there was still not so much known about microplastics. I’ve been doing this for quite a while, since about 2016 or so. It was really strange that no one had used oil before, but it’s something that chemists wouldn’t associate with water purification. Everybody before me was looking at filtration; so, putting it through a sieve to take the plastics out. I was trying that and it didn’t work. I identified that there must be a different way because it’s slow, tedious and it just won’t work.

So, you’ve done the successful experiments, you’ve won the awards from companies like Google, and everyone is psyched on it. How do you now apply it to the real world?   

That’s quite difficult, I was just really overwhelmed for a bit with all the different media attention towards me. I also felt like I was at a bit of a dead-end, like I didn’t really know how to progress. But then I approached some other people who have done similar science projects and they said I should approach an engineering company. So currently where I am is looking at an engineering company who’ve come back with a research plan. What they can do is apply a more professional aspect of building things and quantifying things, which I just can’t do on my own scale. They’ll then run tests on a much bigger prototype in their labs. What comes after that, is that I could myself work on the manufacturing… but I feel like that will take a lot of bandwidth and it will be a full-time company for me, and what I really love is coming up with ideas and testing them on a small scale. So, I’m looking at possibly licensing the idea to other already existing filtration companies so they can incorporate it into a system or a wastewater treatment facility. But I do want to leave it relatively open so it can be used in a wide field of applications. Ultimately the more people who work on it independently, hopefully the more it will be used.

Because the ultimate goal is cleaning our oceans.

Yeah, and what I’m actually looking at now which is quite interesting is how to build a filter that one could put into ships to clean the water that they use while cooling the engines. That filter could be put into ships that already exist, so you wouldn’t need new ships and as a by-product of shipping, so to speak, you could clean the water.

Is that part of your uni work or do you work on that in your own time?

No, I’m just in my second year of a bachelor, so I’m still doing a really broad course. This is just my own time.

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