Engineering news
Engineers at the University of California, San Diego, have designed tiny micromotors that could one day be used to clean up carbon dioxide pollution in oceans.
The “enzyme-functionalised micromotors” can move rapidly in water, remove carbon dioxide and convert it into calcium carbonate. The team believes carbon dioxide scrubbing micromotors could one day be used in water treatment facilities, similar to desalination plants, to decarbonate water at an industrial scale.
The team demonstrated that the micromotors could remove 90% of the carbon dioxide from a solution of deionised water. When placed in a sea-water solution the micromotors removed 88% of the carbon dioxide in the same timeframe.
Virendra Singh, a researcher in the study, said: “We’re excited about the possibility of using these micromotors to combat ocean acidification and global warming.”
The micromotors are six-micrometre-long tubes with an an outer polymer surface that holds the enzyme carbonic anhydrase, which speeds up the reaction between carbon dioxide and water to form bicarbonate. Calcium chloride, which is added to the water solutions, helps convert bicarbonate to calcium carbonate.
The micromotors’ fast and continuous autonomous movement induces efficient solution mixing, leading to faster carbon dioxide conversion.
To fuel the micromotors in water, the team added hydrogen peroxide, which reacts with the inner platinum surface of the micromotors to generate a stream of oxygen gas bubbles that propel the micromotors.
When released in water solutions containing as little as 2-4% hydrogen peroxide, the micromotors reached speeds of more than 100 micrometres per second.
Singh said that the next step for the research was to develop micromotors that can be propelled just by water, without “the need for hydrogen peroxide or expensive platinum catalysts”.