A team of researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory have found a means to remove carbon dioxide (CO2) from coal-fired power plant emissions more efficiently and at lower costs.

By appending a diamine molecule to the sponge-like solid materials known as metal-organic-frameworks (MOFs), the researchers more than tripled the CO2-scrubbing capacity of the MOFs, while reducing parasitic energy, which is the energy, required to operate the scrubbing equipment.

"We've shown that diamine-appended MOFs can function as phase-change CO2 adsorbents, with unusual step-shaped CO2 adsorption isotherms that shift markedly with temperature and result in a much higher separation capacity," says Jeffrey Long, a chemist with Berkeley Lab's Materials Sciences Division and the University of California (UC) Berkeley.

"The step-shaped adsorption isotherms are the product of an unprecedented cooperative process in which CO2 molecules insert into metal-amine bonds, inducing a reorganization of the amines into well-ordered chains of ammonium carbamate," he says.

The research is published in the journal Nature.