Mineral sieve filters out carbon from flue gases

A CHEAP mineral membrane that filters carbon dioxide from power station flue gases could make it easier to dispose of the greenhouse gas in old oil wells.

But while the power industry is excited by the prospect, environmentalists say it will only serve to delay more fundamental action on greenhouse gas emissions.

The mineral membrane acts as a molecular sieve: it exploits the fact that CO₂ molecules are very slightly smaller than molecules of nitrogen, the main component of flue gas. With a diameter of 0.33 nanometres, CO₂ passes through the new membrane over 100 times as…