Illustration: ikonaut

6. The activation: clean energy
The nanoporous catalyst is activated using green resources such as light, magnetic fields or mechanical vibrations.

5. The goal: breaking pollutants down into harmless residues
The radicals react with all the synthetic pollutants in the water, whether it’s pharmaceuticals, pesticides or other chemicals. They break them down into harmless molecules such as water, oxygen and carbon dioxide. The polymer membranes remain clean. The treated water can now be returned into the water cycle.

4. The process: A mini-cleaning team
These electrical charges divide the water (dark blue) and oxygen molecules (light blue) into highly reactive radicals (red), which are what do the real cleaning.

3. The material: a mini-network on polymers
When energy is supplied, a complex nanoporous network is activated on the surface of the polymer membranes. Every nanoparticle (the yellow diamonds) becomes both negatively and positively charged. This results in billions of surface charges in the smallest pores of the membrane (the black dots) in just a fraction of a second.

2. The idea: a nanoporous catalyst
The catalyst comprises polymer membranes that are mounted in a device through which the wastewater passes. The membranes are black because of the special nanomaterial of which they are made.

1. The problem: non-degradable substances in our wastewater
Wastewater from laboratories, the pharmaceutical industry and hospitals contains synthetic micropollutants, such as hormones and drugs. They are difficult to break down and remain in the food chain. Up to now, they have been treated using chemicals or with UV light, but this method is not efficient with turbid wastewater. The ETH spin-off Oxyle has now developed a nanoporous catalyst to do the job.