Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Carbon Dioxide Removal
Name: Daniel T.
Status: educator
Age: 20s
Location: N/A
Country: N/A
Date: 7/20/2004


Question:
I have been trying to find way to explain how to remove carbon dioxide from exhaled air. Either I am looking for an easier way or more details about other methods. Currently this is how I understand it can be achieved...if you bubble exhaled air through a liquid mixture of water and Portland cement the alkaline solution will react with the acidy gas of CO2, and the CO2 free air would escape, until the solution becomes a base...or you can use a common alkaline metal like calcium or potassium and use that instead of Portland cement to make the alkaline solution. I have also heard just mixing or bubbling the exhaled air through water will extract the CO2, because of CO2's solubility in water that would make carbonic acid...and from my calculations carbonic acid is heavier than water and would settle to the bottom of the water the air was bubbled through. The problem is since its an odorless, colorless gas how do I know if that is what is happening?...is there a certain temperature the gas and/or the water has to be for the carbon dioxide to be extracted. Is there any easier way to extract carbon dioxide from exhaled air? Something along the lines of electrochemistry perhaps...If I ran an electric current through the alkaline solution OR through the water/carbonic acid solution and used magnesium cathodes/anodes could I attract and extract the carbonic acid out of the water or the solution? So that I could have pure CO2 escape in a tube....the same way you might separate water into hydrogen & oxygen gases through electrolysis. This is all i know on the subject any clarification would be welcomed or if you have any new methods or ideas I am all ears..Thanks for the assistance...And I LOVE THIS WEB SITE..what a blessing thank you again


Replies:
Daniel,

You could first pass the exhaled air through a drying agent to remove most of the water. Then route the dried exhaled gas mixture through a bed of sodium or potassium hydroxide pellets to remove the CO2. By the way, carbonic acid (H2CO3) is not a liquid -- it is a rather imaginary (unstable) combination of CO2 dissolved in water. If one would attempt to isolate it, one would obtain CO2 and water.

Regards,
ProfHoff 881



Click here to return to the Chemistry Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory