Dissolving carbon dioxide from air without dissolving any other gases.

[nst.john]

Hello,

Me and two other people are doing a science research competition for high school students and for our project we thought of a machine that takes in air through a pump and dissolves CO2 and only CO2. The problem is I don't know what to put in for a solution or pure liquid that would dissolve the CO2. I thought about water but I don't know how to find the pressure needed to dissolve a gas, and also heard about monoethanolamine which dissolves CO2 but don't know how to make it or if it would be very effective. If you can either give me an equation or method to finding the pressure needed to dissolve gases in water, or if MEA is effective or any other methods to do this that would be great.

Thanks!

 

[SteamKing]

Air is a mixture of different gases, not a solution.

There are various methods of scrubbing CO2 from breathable atmospheres in confined spaces, like submarines and spacecraft :

http://en.wikipedia.org/wiki/Carbon_dioxide_scrubber

 

[Borek]

For a simple dissolution check the Henry's law. In the case of CO₂ things get more complicated, as CO₂ reacts with water creating carbonic acid, if it gets neutralized, more CO₂ can be dissolved. That's more or less how MEA works, but it is also possible with any base - it is just the further separation that can make some substances better.

Also, see http://www.sciencedirect.com/science/article/pii/036031999500007Z