Purifying water: PhD student Krithika Ganesan tackles the growing challenge of filtering out contaminating chemicals

As a Computational Chemistry PhD researcher at the University of Antwerp, Krithika Ganesan focuses on understanding how atomic-scale interactions influence material performance in sustainable energy and environmental applications.

For the non-scientific community, it might be difficult to grasp what exactly she does. That is why the university runs an annual PRESS>SPEAK 2026 writing competition. It is designed to hone researcher’s communication skills while giving them an opportunity to share their work with a wider audience.

Originally from India, Ganesan (pictured above) has been studying in Belgium for over two years. Besides her research work, she likes to travel, try new vegan cuisine, paint “and live in vibrant colours”.

Here is Ganesan’s winning text about her new strategy to access the hidden world of molecular interactions that endanger the water we drink, the air we breathe.

A Glass of Water: an invisible science

A ‘simple’ glass of water is anything but simple. Which bottles to buy? Which filter to choose? Maybe a purifier in the kitchen? By the time we pour a glassful, the water has passed through layers of technology, materials, and decisions. These layers give us something clear, innocent, and easy to trust.

That trust depends on separation technologies most of us never see. These systems don’t just clean drinking water; they also purify air, separate chemicals in factories, and help remove contaminants from the environment. At their core are materials designed to capture unwanted molecules and let everything else pass.

For decades, this has worked by using ‘molecular velcro’, where contaminants brush against a surface and are filtered out. Some contaminants, such as ‘forever chemicals’    like PFAS, or dry organic pollutants which are tiny, persistent, and difficult to catch. They slip through the so-called Velcro and remain forever. As new chemicals enter our water, air, and industrial systems, separating them efficiently has become a growing challenge. 

What if contaminants could stick to the materials/filters more effectively?

Krithika Ganesan studies materials based on titanium dioxide, which is stable, cheap, and environmentally safe. What makes these materials different is how their surfaces behave. Under the right conditions, titanium atoms can form unique hybrid surface which makes contaminants stick easily to the surface.

This means we can selectively target and capture certain molecules while ignoring others. This kind of control could improve technologies ranging from water and air purification to industrial separations and environmental cleanup. But these interactions are too small to observe with even the most powerful microscopes. The key moments happen at the scale of atoms and electrons, currently far beyond our reach.

To access this invisible world, she uses computational simulations that recreate chemical interactions atom by atom. Using mathematical models and high-performance computing, she builds virtual systems where molecules approach a surface, electrons rearrange and bonds either form or fail. Her  simulations allow her to slow time down and observe processes that happen too quickly and are too small to measure directly. By understanding exactly why certain molecules stick strongly while others escape, we can tune the surface chemistry.

This molecular-level insight allows us to design separation technologies that are simpler, efficient, and less energy-intensive. Fewer treatment steps, lower waste generation, and higher selectivity all become achievable when chemistry does more of the work. The outcome still appears ordinary: clean water, purified air, reliable products. Yet behind that apparent simplicity lies a precise chemical rhythm, unfolding quietly one atom at a time; turning a ‘simple’ glass of water into a triumph of invisible design.

Photos (main image) ©Brendan Church/Unsplash; courtesy Krithika Ganesan; ©Unsplash