German researchers develop microbots to clean up lead from water

German researchers have developed self-propelled tiny microbots that can remove lead or organic pollution from contaminated water, said the Max Planck Institute Stuttgart on Friday.

Working with colleagues in Barcelona and Singapore, German researchers used graphene oxide to make their microscale motors, which are able to adsorb lead from industrial wastewater from a level of 1,000 parts-per-billion to down to below 50 parts-per-billion in just an hour.

The lead can later be removed for recycling, and the micromotors can be used over and over again.

"The outer shell of the microbot, which is graphene, captures the lead," said Samuel Sanchez, group leader at the Max Planck Institute for Intelligent Systems in Stuttgart. He added that the inner layer of platinum works as the engine, decomposing hydrogen peroxide as fuel so that the bot can self-propel.

When hydrogen peroxide is added to the wastewater, the platinum decomposes it into harmless water and oxygen bubbles, which are ejected from the back of the microbot to propel it forward.

"It's important to use a system of pollutant removal that doesn't produce any additional contamination," he noted.

Heavy metal contamination in water stems from industrial activities and poses a serious risk to public health and wildlife. These new microbots, which are smaller than the width of a human hair could offer a solution that is potentially faster and cheaper than current methods of water cleaning, as well as being environmentally friendly, according to the Max Planck Institute.

"We now plan to develop our microbots to be able to collect other contaminants, as well as reducing the cost of making them and being able to mass-produce them," said Sanchez.