Submarine crews could be breathing much healthier air thanks to miniscule devices based on 62 year-old technology. Currently, carbon dioxide is removed from the air in submarines through a reaction with chemicals such as calcium hydroxide. Chemical engineers from England’s University of Bath are collaborating with mechanical engineers from Duke University in the US, to develop a chemical-free filtration system. It utilizes seawater and tiny folded wire mesh rings known as Dixon rings.

It has been known for a long time that sea water absorbs CO2. The researchers, however, are faced with designing a system that could fit within the close confines of a submarine, or other undersea habitat. That’s where the Dixon rings come in. Only 3mm across, the rings’ mesh construction provides extra surface area for the absorption of CO2.

The system consists of a column packed with Dixon rings. Seawater and “used” air are pumped through the column (and rings) in counter-current directions. This chaotic interaction results in the air being scrubbed of its CO2, which is then discharged into the sea.

According to the Bath scientists, not only will this technology do away with the need for chemicals, but it will also allow crews to stay undersea for longer periods.

The study is funded by a three-year £380,000 (US$563,109) grant from the US Office of Naval Research.