Researchers have been searching for an ideal substance that can soak up carbon dioxide (CO2) in smokestacks before the greenhouse gas enters the atmosphere. Existing CO2 sponges have drawbacks: they may be too expensive, take too much energy to operate, do not capture much carbon or are unstable over long periods. Now chemical engineer Christopher Jones of the Georgia Institute of Technology and his colleagues have developed a solid adsorbent that is both strong and long-lasting.

The material contains nitrogen-rich compounds called amines grown on porous silica. The amines are bases that neutralize the acidic carbon dioxide gas. Heating the substance releases trapped CO2 for later storage. The low-cost material has a hyperbranching structure, which helps it hold many amines, Jones explains, and the strong chemical bonds holding it together allow it to be reused often. The absorbing findings appear in the March 19 Journal of the American Chemical Society.