Electrochemistry offers new way to tackle rising carbon dioxide – extract it from seawater

Capturing carbon dioxide from seawater to tackle climate change could be cheaper and more energy efficient than existing systems that capture it from air. Chemical and mechanical engineers at the Massachusetts Institute of Technology (MIT) have used an electrochemical system to take advantage of the fact that oceans and other surface waters act as large carbon sinks that have absorbed 30% to 40% of anthropogenic CO₂ emissions since the industrial revolution.

Existing methods for removing carbon dioxide from seawater apply a voltage across a stack of membranes to acidify a stream of water by splitting it. But these membranes are expensive, and reagents are needed to drive the overall electrode reactions at either end of the stack adding to the cost.