It’s not easy to break down compounds such as mineral oils, paints, and organic solvents in wastewater, but a group from Germany believe they have found a way. To remove these tricky materials from the water supply, scientists from the Max Planck Institute for Intelligent Systems in Stuttgart have invented tiny, jet-propelled micro engines to treat waste water. The mini engines take advantage of iron, platinum, and hydrogen peroxide to break pollutants down into carbon dioxide and water that is clean enough to use again.
The microengines are composed of an inner layer of platinum and an outer layer of iron. When hydrogen peroxide is added to a contaminated solution, it acts as a fuel for the platinum micromotors and helps to begin an oxidation process that degrades pollutants on the iron layer. Known as the Fenton reaction, the microcleaners break down toxins into water and carbon dioxide.
The tiny tubular device is self-propelled, relying on the reaction between hydrogen peroxide and iron to run the inner platinum micromotor. When the platinum comes into contact with hydrogen peroxide, the platinum becomes a catalyst for a reaction that turns the hydrogen peroxide into water and oxygen. Small bubbles form and then escape through the tube on one side once it reaches a certain speed. As it moves, more fuel is fed through the front end. Since the iron layer is magnetic, the little jets have the added bonus of being able to be steered to specific pollutants instead of moving along random trajectories.
The microengines are so far only suited for small scale use, but researchers hope that their methods will be applicable on an industrial scale. They look forward to the day where compounds like pesticides and paint residue can be cleaned by a swarm of tiny, self-propelled devices.
Images via the Max Plank Institute and Wikicommons user Anita Martinz