It is estimated that up to half of the carbon dioxide that is released by humans ends up in the rivers, lakes and oceans of the world, slowly lowering their pH and acting as a huge heat sink, contributing to global warming. But Nanoengineers from the University of California have come up with an ingenious solution to help clear this CO2 pollution – tiny micromotors smaller than the width of a human hair.
hese six-millimetre-long tube motors create usable carbon solids with an outer polymer surface layer containing the carbonic anhydrase, which speeds up the reaction between carbon dioxide and water to form bicarbonate. This is then reacted with calcium chloride to form calcium bicarbonate, a solid that is found in eggshells and is used in calcium supplements and cement.
"In the future, we could potentially use these micromotors as part of a water treatment system, like a water decarbonation plant," says Kevin Kaufmann, co-author of the study.
This proof of concept, published in the journal Angewandte Chemie, shows that the micromotors removed 90 per cent of the carbon dioxide from a deionised water solution in only five minutes and this was reduced by only two per cent when used in sea water.
"We're excited about the possibility of using these micromotors to combat ocean acidification and global warming," says Virendra V. Singh, co-first author of this study.
Unfortunately we cannot expect to see hoards of micromotors cleaning up our oceans just yet, as they require prohibitively expensive platinum to make and power the devices. Research is now looking to develop them so that they can be propelled by water alone.
"If the micromotors can use the environment as fuel, they will be more scalable, environmentally friendly and less expensive," concludes Kaufmann.