SAN FRANCISCO, Sept. 17 (Xinhua) -- Researchers at the University of California, Berkeley, have created a new material that can absorb carbon monoxide (CO) far better than other materials, with potential applications in industrial processes like syngas production, where CO is a key player, and reactions where CO is an unwanted contaminant.
The new material is a metal-organic framework (MOF), a porous material with a growing list of applications, that incorporates chains of iron atoms tuned to attract CO and exclude other chemical compounds. When CO binds to an iron atom in the MOF, it changes the environment of neighboring iron atoms to make them even more attractive to CO, creating a chain reaction.
The CO binding flips the spin state of iron, hence Jeffrey Long, a UC Berkeley professor of chemistry and faculty scientist at Lawrence Berkeley National Laboratory, gives a new terminology for the material: spin-transition MOFs. Two years ago, Long stumbled across the first of this type of cooperative adsorbent when he created a MOF that adsorbed carbon dioxide far better than other materials.
"We see this cooperative adsorption effect where binding at one site activates the neighboring sites, which means that all of a sudden you go from very little adsorption to essentially saturating the material with CO," Long was quoted as saying in a news release.
In practice, the MOFs would adsorb CO at room temperature, and then be heated slightly to drive off the CO, readying the MOF for reuse. The spin-transition MOFs can be precisely tuned so that a small rise in temperature - from 20 to 60 degrees Celsius, for example - would start its release of CO, requiring significantly less energy than other capture or storage technologies, such as cryogenic distillation.
Initial calculations showed that the MOF requires just 32 percent of the energy to capture and reuse CO as a commercial, liquid absorbent process for recovering CO, which is called COSORB.
The research was published in the journal Nature.