Carbon dioxide scrubber

From Wikipedia, the free encyclopedia

A carbon dioxide scrubber is a device which absorbs carbon dioxide. It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or airtight chambers.

Carbon Dioxide scrubbers are also used in Controlled Atmosphere (CA) storage.

Contents 1 Strong bases 2 Monoethanolamine 3 Activated Carbon 4 See also

[edit] Strong bases

Various strong bases such as soda lime, sodium hydroxide, potassium hydroxide, and lithium hydroxide are able to remove carbon dioxide by reacting with it. In particular, lithium hydroxide is used aboard space craft to remove carbon dioxide from the atmosphere. It reacts with carbon dioxide to give lithium bicarbonate:

2 LiOH(s) + 2 H₂O(g) → 2 LiOH.H₂O(s)

2 LiOH.H₂O(s) + CO₂(g) → Li₂CO₃(s) + 3 H₂O(g)

The net reaction being:

2 LiOH(s) + CO₂(g) → Li₂CO₃(s) + H₂O(g)

[edit] Monoethanolamine

Monoethanolamine solutions absorb carbon dioxide when cold, and release it when warmed.

[edit] Activated Carbon

Activated Carbon can be used as a Carbon Dioxide scrubber. Air with high Carbon Dioxide content (such as air from fruit stores) can be blown through beds of activated carbon and the Carbon Dioxide will adsorb to the activated carbon. Once the bed is saturated it must then be "regenerated" by blowing low Carbon Dioxide air (ambient air) through the bed. This will release the Carbon Dioxide from the bed, and it can then be used to scrub again.

[edit] See also

• breathing
• Greenhouse gas