We know that real trees soak up carbon from the atmosphere — but fake trees?
A cheap plastic that removes carbon dioxide (CO2) from the atmosphere? “Yes,” says a team of chemists at the University of Southern California’s (USC) Loker Hydrocarbon Research Institute, led by Nobel Prize winner George Olah. Science Now reports on their work with an inexpensive polymer called polyethylenimine or PEI.
But how to maximize its absorption capabilities? Olah’s team dissolved the polymer in a solvent and spread it out, peanut-butter-style, on fumed silica — you know, like the stuff in those desiccant packets in your electronics packaging (“Do not eat,” by the way). It’s also used as a stabilizer for lipstick and other make-up.
Here are the geeky details from Science Now:
When the researchers tested the new material’s CO2-grabbing abilities, they found that in humid air—the kind present in most ambient conditions—each gram of the material sopped up an average of 1.72 nanomoles of CO2. That’s well above the 1.44 nanomoles per gram absorbed by a recent rival made from aminosilica and among the highest levels of CO2 absorption from air ever tested, the team reported last month in the Journal of the American Chemical Society. Once saturated with CO2, the PEI-silica combo is easy to regenerate. The CO2floats away after the polymer is heated to 85°C. Other commonly used solid CO2 absorbers must be heated to over 800°C to drive off the CO2.
Team member Surya Prakash says the polymer could also be used to make vast farms of artificial “trees” that could suck CO2 out of the atmosphere, much like real ones do. Prakash and Olah have been trying to stand the carbon paradigm on its ear for the past several years, exploring it as a positive rather than a negative for the planet. “People tend to think of CO2 as a problem rather than a resource,” he explained. “We want to take CO2, and instead of burying it underground, use it as a raw material, and convert it with alternative energy sources back to fuels and feedstocks.”