Solid materials based on polyethylenimine show great promise for reducing carbon dioxide emissions at a lower cost than today’s technology, and could even capture CO2 directly from the air, according to a report in the Journal of the American Chemical Society.
In the paper, authors Alain Goeppert, Miklos Czaun, Robert B. May, G. K. Surya Prakash, S. R. Narayanan and Nobel laureate George A. Olah of the University of Southern California say that polyethylenimine is a readily available and inexpensive material. On the other hand, they say, existing methods for removing carbon dioxide from smokestacks and other emissions sources are energy intensive and don’t work well.
Their tests show polyethylenimine achieving some of the highest carbon dioxide removal rates ever reported for humid air, under conditions that hamper other related materials.
The researchers say that CO2 should be seen as a valuable feedstock for fuels and materials, instead of as a problematic byproduct of combustion. They say that some of the needed CO2 will have to be obtained directly from the atmosphere.
While about half of manmade CO2 emissions come from large industrial sources, the rest come from distributed sources including transportation, home heating and cooking. For these smaller sources, CO2 capture at the source is not practical, so researchers are examining how to capture the gas directly from the atmosphere. This approach would allow carbon-capture infrastructure to be placed where it would have the smallest environmental impact, and also in locations close to CO2 recycling centers, the report authors say.
Their research suggests that polyethylenimine could be used to clean up CO2 in the open atmosphere, in smokestacks or on submarines. After capture, the materials give up the CO2 easily so that it may be sequestered or used to make other substances. The capture material can then be reused many times without losing efficiency, the researchers said.
They noted that the separation and recovery of CO2 from ambient air on a larger scale is still in its infancy. And while several underground carbon capture and sequestration (CCS) projects have been proposed, the authors said none of the existing technologies have been proven on the enormous scale necessary.
Carbon Capture Journal reports that 2011 was a mixed year for CCS projects, with funding agreed for or construction starting at some major projects, while other projects were cancelled. One of the highest profile cancellations was American Electric Power’s decision to shelve plans for its Mountaineer coal-fired plant in New Haven, W.Va., which had secured a cooperative agreement with the U.S. Department of Energy.
Meanwhile, construction began at an Archer Daniels Midland Company ethanol plant that is projected to capture and store one million tons of carbon dioxide a year.