First ever porous liquid shows promise for carbon capture
Liquids dissolve stuff, enveloping the substance to be dissolved with friendly molecules that welcome the material to rest in a bath of fluid. Constantly in motion, the fluid would not be described as having "pores", or holes, where the dissolved substance enters (although recent studies have sought to describe the nature of "cavities" between molecules and how they influence the dissolving properties of solvents).
Up until now, only solids have offered the power of pores -- the ability to form holes of a certain size that can be useful for stopping some materials while others pass through. But scientists at Queen's University of Belfast, have just changed all that.
They have created the first porous liquid, specially designed of cage-like molecules sized to capture small molecules like methane or carbon dioxide, but too large to be filled by the liquid solvent in which they are dissolved. The resulting soup behaves quite differently from the standard liquid. For example, the porous liquid can capture up to 8 times more methane gas than could be dissolved.
Most carbon capture and storage systems depend on liquid solvents or reaction systems, because liquid systems more easily retrofit onto existing power plants. Current technology relies mostly on amines or carbonates to capture the carbon dioxide from the power plant emission stream. The carbon dioxide can then be released from the solvents and liquified for injection into storage sites.
Alternatives like engineered porous liquids could offer better options for carbon capture, a technology which may be essential to bridge the gap between increasing emissions of global warming gases and commitments to adopt alternative energy solutions to reduce these climate changing emissions.
Even if we can avoid the risks of storing carbon dioxide deep in the earth, porous liquids could become important for other technological breakthroughs. We cannot help but think of most of the biochemical miracles our bodies perform; our cells use molecules built precisely to catalyze the chemical reactions we need to survive, all in the liquid medium of our watery beings.