A recent article describes a new material developed by a team of researchers at the University of Southern California. The material, fumed silica impregnated with polyethlenimine, readily absorbs CO2 from the air and releases the CO2 if heated. The article speculates that “large artificial trees made from the material could be used to lower the concentrations of the greenhouse gas in the Earth’s atmosphere.” In addition, the researchers hope to find a low-cost method of turning the CO2 into methanol, a fuel and a chemical feed stock. Here is a link to article on USC News.
Hal Harvey writes about an important caveat in the work:
Well, this is interesting. A low-cost device that scrubs CO2 from ambient air would be useful.
A quick reality check, though: The scale required for these things is almost unfathomable. If the scrub device was free and ubiquitous, and we wanted to build a system that scrubbed and sequestered 1Gt carbon per year (a good contribution, but only about 10% of what we need), the sequestration system (capture sites, compression, pipelines, drilling, injecting, capping, monitoring) would be 1/3 as big as the entire global oil system. That is a many trillion dollar system, with a vast amount of technology, land-use, logistics, etc. For 1Gt Carbon per year.
Olah has another idea, which is to use the captured CO2, add energy from renewable sources, and make methanol, which can be burned in modestly modified autos. That avoids capture and sequestration, but (a) puts the CO2 right back into the atmosphere, and (b) requires a huge additional source of renewable energy. Thermodynamics is very unforgiving. Still, after we displace coal, that would be better than burning gasoline. (Until we displace coal, it is silly to use renewables to offset gasoline.)
USC Viterbi School of Engineering. Photo by Lan56. Used under the Creative Commons Attribution-Share Alike 3.0 Unported license (http://goo.gl/DgzJU).