New technique to capture CO2 could reduce power plant greenhouse gases

Metal-organic frameworks are highly porous, making them ideal for absorbing gases and liquids. This graphic shows the interior of a MOF based on the metal magnesium (green balls), and has added molecules - tetraamines (blue & gray) - added to the pores to more efficiently absorb carbon dioxide from power plant emissions. (UC Berkeley graphic by Eugene Kim) A big advance in carbon capture technology could provide an efficient and inexpensive way for natural gas power plants to remove carbon dioxide from their flue emissions, a necessary step in reducing greenhouse gas emissions to slow global warming and climate change. Developed by researchers at the University of California, Berkeley, Lawrence Berkeley National Laboratory and ExxonMobil, the new technique uses a highly porous material called a metal-organic framework, or MOF, modified with nitrogen-containing amine molecules to capture the CO₂ and low temperature steam to flush out the CO₂ for other uses or to sequester it underground. In experiments, the technique showed a six times greater capacity for removing CO₂ from flue gas than current amine-based technology, and it was highly selective, capturing more than 90% of the CO₂ emitted. The process uses low temperature steam to regenerate the MOF for repeated use, meaning less energy is required for carbon capture. "For CO₂ capture, steam stripping - where you use direct contact with steam to take off the CO₂ - has been a sort of holy grail for the field.