Edible Carbon Dioxide Sponge

Friday, September 23 2011

When a yellow dye, called a pH indicator, is placed within the voids of the metal-organic frameworks (MOFs), the crystals turn yellow. However, upon exposure to carbon dioxide, the pH indicator switches to a red color, indicating that the MOF has both reacted and filled up with carbon dioxide. If the crystals are placed away from high concentrations of carbon dioxide, the gas leaves, and the crystals once again turn yellow.

The porous crystals - known as metal-organic frameworks (MOFs) - are made from all-natural ingredients and are simple to prepare. Conventional MOFs, which also are effective at adsorbing carbon dioxide, are usually prepared from materials derived from crude oil and often incorporate toxic heavy metals.

Other features of the Northwestern MOFs are they turn red when completely full of carbon dioxide, and the carbon capture process is reversible. The findings were made by scientists working in the laboratory of Sir Fraser Stoddart, Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences.

“We are able to take molecules that are themselves sourced from atmospheric carbon, through photosynthesis, and use them to capture even more carbon dioxide,” said Ross S. Forgan, a postdoctoral fellow in Stoddart’s laboratory. “By preparing our MOFs from naturally derived ingredients, we are not only making materials that are entirely nontoxic, but we are also cutting down on the carbon dioxide emissions associated with their manufacture.”