How can microbots be used to clean contaminated water?

Swarms of hundreds of thousands of microbots each smaller than the width of a human hair can be deployed to industrial wastewater to remove heavy metals, according to a recent study from the Max-Planck Institute for Intelligent Systems in Stuttgart, Germany; the Institute for Bioengineering of Catalonia in Barcelona; and the Catalan Institution for Research and Advanced Studies in Barcelona.

In just one hour, according to the researchers, 95 percent of the lead found in industrial wastewater can be removed. The method is being developed as alternative to traditional methods like filtration.

In the study, the microbots removed lead from wastewater by absorbing the metal into their outer layer. A central layer made of nickel allows the microbots to be easily controlled by an external magnetic field, while an inner platinum layer reacts with a hydrogen peroxide agent added to the water, allowing the microbots to propel themselves using the bubbles produced. When the microbots are done absorbing the lead, their magnetic fields are used to collect them from the water, whereupon they can be cleaned and deployed again.

A video of the microbots in action can be found at Phys.org.