SF Carbon Dioxide Process

[mishalak]

Huh. I just had a more or less crazy idea. Could a semipermeable membrane be used to separate carbon dioxide from an atmosphere at a low energy cost? If so it might be possible to build a system using specialized unicellular algae or cyanobacteria that would be more efficient at using sunlight under high CO2 conditions that would be the first step in a really permanent sequestering system.

I could see using something like this in a science fiction story. Perhaps not as the total solution for global warming, but something that people in the future are doing as part of the fight against global warming.
 

Comments

[pompe]

I think it would be difficult because the CO2 molecule is both small and not charged, which it shares with many other atmospheric molecules, and because the fraction of carbon dioxide in the atmosphere isn't that large. Might work better with dissolved carbon dioxide in the oceans, though.

[mishalak]

Ah, well then I'm left with applied phlebotinum then.

It just seems there ought to be a low(er) energy trick to separate out CO2 than fractional distillation of air. Perhaps a reversible chemical trick instead of something as direct as pressure on a semipermeable membrane.

[pompe]

Maybe you could use some sort of energy absorbtion process, basically utilize the same properies which makes CO2 a decent greenhouse gas to begin with.