Pushing the boundaries of wastewater treatment
In 2025, the Young Scientist award went to was presented to Olivier Monfort from the Faculty of Natural Sciences of Comenius University Bratislava. The Slovak Academy of Sciences and the Association of Slovak Scientific and Technological Societies conferred this award on him as part of the “Scientist of the Year of the Slovak Republic” initiative. Every year the event honours leading scientific figures from all fields of science and technology. Even though he originally hails from Brittany, his scientific career has taken him from the shores of the Atlantic to landlocked Bratislava. He is Head of the Department of Inorganic Chemistry at the Faculty of Natural Sciences, where he leads the M2 research group. He received the award for new findings on the modification of MXenes to increase their efficiency in degrading persistent pollutants in water and for his significant contribution to elucidating the mechanisms of photocatalytic reactions in wastewater treatment.
Your research group is called M2. What does the name signify?
I set it up together with my colleague Martin Motola; and the acronym is a bit of a pun: it comes from our surnames - Monfort and Motola - and it also reflects our expertise: materials and mechanisms. Our group also includes two postdocs and six PhD students. We are continuing the research started by our former supervisor, Professor Gustáv Plesch.
What exactly do you study?
We work on nanomaterials designed for wastewater treatment. Our aim is to understand how and why the processes we investigate operate and to determine whether it makes sense to apply them to actual wastewater. Another goal is to develop non-toxic, sustainable and efficient nanomaterials. I personally focus on iron-based materials. At present I also focus on research into iron-based MXenes.
What are MXenes?
MXenes are a new category of nanomaterials that were discovered relatively recently – in 2011 – and are currently attracting great interest. They are two-dimensional (2D) materials, such as graphene and transition-metal dichalcogenides (TMDs), but they are composed of metallic carbides, nitrides or carbonitrides. These nanomaterials have specific properties; their surface can be modified, which makes it possible to influence their reactivity. In other words, we can “design” their surface chemistry according to the intended application.
What uses of MXenes are you exploring in your group?
Until now, MXenes have mainly been investigated for energy applications, but at the Faculty of Natural Sciences of Comenius University Bratislava we are pioneers in using them in oxidised form for wastewater treatment. In the laboratory we study how MXenes react with molecules present in wastewater. Current systems cannot fully purify the water, and untreated pollutants, like antibiotic residues, are released into the natural environment. In our research we use both water that we “contaminate” ourselves for experimental purposes, but also real wastewater from the municipal wastewater treatment plant in Bratislava. The processes we study are known as advanced oxidation processes because they make use of highly reactive, oxidising radicals that effectively degrade organic molecules.
You also study how MXene reactions can be activated by sunlight. How does that work?
The material itself, merely by being present in water, cannot completely break down pollutants: you have to supply it with energy. For this purpose we use light. In the laboratory we use a photoreactor that generates UVA radiation similar to natural sunlight. We activate the nanomaterials with light; this principle is called photocatalysis. Another way to increase the efficiency of degradation is to use green oxidising agents, which promote the formation of radicals. One of the substances we use is hydrogen peroxide, which is inexpensive and non-toxic. When our nanomaterial is exposed to light, hydroxyl radicals are generated. These are extremely reactive and react with a wide range of pollutants.
How do you expect your methods can improve treatment in the future?
The point of developing such advanced methods is to deploy them everywhere! In everyday life they can be used as an additional step in water treatment. The goal is to increase the share of treated wastewater that can be reused in the circular economy, for example for irrigating fields. The challenge is how to achieve this in large countries such as Spain, Greece or France: particularly in their southern parts they are already facing serious water shortages. The situation is also worsening in Brittany, where I come from. There used to be sufficient groundwater reserves, but in recent years there have been summers when watering gardens is banned because there simply is no water.
You received the Young Scientist of the Year award. Does that mean you have achieved something new in this field?
Yes, there were two areas in which I published high-quality papers. In the first area, I focused on clarifying mechanisms that had not previously been fully described or had been interpreted incorrectly. The second area involved the MXenes we mentioned. The results we published were related to surface modification by oxidation, specifically for wastewater treatment. I should stress, however, that the award I received is a result of the collaboration that I coordinate. I am very grateful for this recognition, because it is further proof that we are capable of doing top-level research in Slovakia.
Who are your collaborators?
We learned how to prepare MXenes in the United States; their discoverer, Professor Yury Gogotsi, personally visited Slovakia several times. His former PhD student, Professor Michael Naguib from Tulane University in New Orleans, is our partner and often collaborates with us. My postdoc Shalu Shalu completed a research stay with him. We collaborate with CNRS and Université Clermont Auvergne in France on the treatment processes specifically, and we also have partners in China and the Czech Republic. At home we collaborate with the Centre for Nanotechnologies and Advanced Materials (CENAM) at the Faculty of Mathematics, Physics and Informatics, Comenius University Bratislava, and with the Slovak University of Technology.
How did you get from France to Bratislava? What made you even consider university studies in Slovakia?
I already learned about Slovakia in secondary school. Our regional capital had twinning arrangements with several cities in Europe and once, when it organised a festival, they invited students from the Metodova Bilingual Grammar School in Bratislava. I was assigned to look after them and I made friends with some of them; afterwards we stayed in touch. I obtained my Bachelor’s degree in chemistry in Brittany, at the Université de Rennes. My supervisor was Czech, he actually described himself as Czechoslovak, and he advised me to look into Master’s programmes in the Czech Republic or Slovakia. I opted for Comenius University Bratislava.
Did you study in English?
No, in Slovak. It was hard until I learnt Slovak, but the teachers were very accommodating and my classmates also helped a lot. After a while I felt so good here that I stayed on to do my PhD. I went back to France for a postdoctoral stay. I then tried to obtain a permanent research position, but it did not work out: I made the short-list several times, but research policy favours foreigners. In the meantime, an opportunity arose to take up an assistant professorship in Bratislava, and I decided to return to Slovakia. I am grateful to France for not selecting me, because I am now proud to be working in Slovakia, where I can demonstrate my abilities and show that Slovakia has great potential.
The French are renowned for their love of gastronomy, good food and wine. How did you adjust to life in Slovakia in this respect?
First of all, I am Breton, not French! I like Slovak cuisine very much, although it is fattier than what I was used to. I loved dumplings with sheep cheese, pierogi, and schnitzels. Unfortunately, I now have to keep to a gluten-free diet, so I can no longer enjoy them. As far as wine is concerned, I was pleasantly surprised by how good your white wines were. Sometimes me and my friends take the "Carpathian Wine Route" and once we met a winery owner who, when he found out I was from France, brought out his very best wines for me to try. That was certainly a case of positive discrimination!
Do you think we are open enough towards foreigners?
Overall I think you are, although compared to France you are still a very homogeneous society, for example in terms of skin colour or religion. Personally, however, I have always felt accepted, especially when people saw that I was making an effort to speak Slovak. The level of internationalisation, at least at our faculty and department, is quite high. Apart from me, our department also has staff from Ukraine, Japan, China and India. I also see the opening of the university’s Welcome Centre as a great step; my PhD students have already used its services and were very satisfied.
Barbora Tancerová