Researchers at the University of Bath have invented a new way to remove health-harming toxins from water – using 3D printing.
The team from the university’s Department of Chemical Engineering say their method removes at least 75% of perfluorooctanoic acid (PFOA) from water and so could become an important tool in future efforts to eliminate the chemicals from water supplies.
PFOA is one of the most common perfluoroalkyl and polyfluoroalkyl substances (PFAS), which are known as forever chemicals due to the incredibly long time they take to break down – in some cases more than 1,000 years.
PFAs are man-made and known for causing health issues, including harms to reproductive, developmental, cardiovascular systems and in increasing likelihood of diabetes.
Sources of PFAS include domestic products, often with water-repellent properties, such as non-stick pans, raincoats, paints, fabrics and firefighting foams.
The University of Bath team’s method uses ceramic-infused lattices – or – made of ink infused with the ceramic indium oxide.
The 4cm ‘monoliths’ are created by extruding the ink from a 3D printer – like squeezing toothpaste from a tube – and forming it into a lattice shape.
Because indium oxide bonds with PFAS, the chemicals immediately stick to the monoliths and can be removed from the water in under three hours, which is compatible with current water treatment plants in the UK and abroad.
While testing has so far found that the monoliths remove 75% of PFAS from water, the team is aiming to increase the efficiency of the process with further refinement.
These tests have also shown that the monoliths become more effective under repeated use – they undergo high-temperature thermal ‘regeneration’ treatment after each use. This is something the researchers are keen to understand more fully with further experimentation.
Dr Liana Zoumpouli, a research associate in the university’s Department of Chemical Engineering, said: “PFAS, or ‘forever chemicals’, are a major focus in water treatment and public health. We have created an efficient way to remove these chemicals from water without using lots of energy.
“Using 3D printing to create the monoliths is relatively simple, and it also means the process should be scalable. 3D printing allows us to create objects with a high surface area, which is key to the process.
“Once the monoliths are ready you simply drop them into the water and let them do their work. It’s very exciting and something we are keen to develop further and see in use.”
While legislators around the world, particularly in the US and EU, have brought in some rules on acceptable levels of PFAS and similar chemicals in drinking water, the researchers say further legislation is likely as the scale of health threats comes into clearer focus.
Prof Davide Mattia, who co-author a report on the research with Dr Zoumpouli, added: “Currently, these chemicals are not strongly regulated in the UK in drinking water, but there are guidelines, and we expect changes in policy quite soon. Water companies are likely to be looking at integrating systems to deal with them.”
The team also includes Drs Alysson Martins, Antonio Jose Exposito and Jannis Wenk.
The research was funded by the Engineering and Physical Sciences Research Council.
