Home
Common Compounds
Exam Guide
FAQ
Features
Glossary
Construction Kits
Companion Notes
Just Ask Antoine!
Simulations
Slide Index
Toolbox
Tutorial Index
Introduction
Measurement
Matter
Atoms & ions
Compounds
Chemical change
The mole
Gases
Energy & change
The quantum theory
Electrons in atoms
The periodic table
Chemical bonds
Solids
Liquids
Solutions
Acids & bases
Redox reactions
Reaction rates
Organic chemistry
Everyday chemistry
Inorganic chemistry
| Environmental chemistry |
History of chemistry
Miscellaneous
Home  FAQ Environmental chemistry | Print | Comment |
| Previous Question | Next Question |
Is there a safe chemical way to remove CO2 from air?
- I know that alkali metal hydroxides (column I and II metal hydroxides) can be used to absorb carbon dioxide (CO2) in an enclosed atmosphere, like in a space craft or submarine. However, they're corrosive and absorb water vapor. (1) Is there any commonly-available material that is not toxic/dangerous that will absorb CO2? (2) What is used in underwater rebreathers/CO2-scrubbers? Thanks.
Garcia Oliver -
Plants absorb CO2, of course, but they take up a lot of room and are slow, inefficient CO2 absorbers.
Most industrial CO2 scrubbers use chemicals that don't meet your criteria. Monoethanolamine (MEA) is used to scrub carbon dioxide from gas streams, but it's corrosive and toxic in very small amounts. Ascarite II
is a very efficient CO2 absorbent, but
it's basically
nonfibrous asbestos covered with sodium hydroxide.
Potassium superoxide is an interesting possibility for spacecraft and submarine CO2 scrubbing, since it regenerates oxygen as it reacts with carbon dioxide:
4 KO2(s) + 2 CO2(g) = 2 K2CO3(s) + 3 O2(g) But it isn't common, and it is quite toxic.Calcium hydroxide (mixed with a small amount of sodium and potassium hydroxides) is used in most underwater rebreathers. The reaction between the hydroxides and CO2 is exothermic, and divers can tell from the warmth of the scrubber canister that the absorption reaction is working. Failure of the canister lid can give the diver a mouthful of hydroxides- called a "caustic cocktail" in diving circles. It's apparently a memorable experience.
You can learn more about the construction and chemistry of rebreathers here.
Related Links
Carbon dioxide sequestration(U. S. Department of Energy)
Climate Change Information KitTechnical information on programs and technologies to reduce carbon dioxide emissions.
http://www.fe.doe.gov/coal_power/sequestration/index.html (10/28/00)(United Nations Environmental Programme)
Physico-Chemical Life Support SystemsBackground information on climate change and its potential impact on human activities and recommended policies and technologies for limiting carbon dioxide emissions.
http://www.unep.ch/iuc/submenu/infokit/factcont.htm (10/28/00)(The Mars Club)
Regenerative Life Support: Carbon Dioxide ControlInformation on several different chemical techniques for purifying air and recycling wastes aboard spacecraft.
http://marsacademy.com/lifes2.htm (3/21/99)(James Atwater)
Regenerative Life Support: Water ProductionDetails on several CO_2_ recycling technologies for life support systems, including lithium hydroxide absorption, molecular sieves, solid phase amines, and silver oxides.
http://ucs.orst.edu/~atwaterj/co2.htm (3/21/99)(James Atwater) Outline of water generation from carbon dioxide using the Sabatier and Bosch processes.
http://ucs.orst.edu/~atwaterj/h2o_gen.htm (3/21/99)
General Chemistry Online! Is there a safe chemical way to remove CO_2_ from air?
Copyright © 1997-2010 by Fred Senese
Comments & questions to fsenese@frostburg.edu
Last Revised 02/23/18.URL: http://antoine.frostburg.edu/chem/senese/101/environmental/faq/co2-recycling.shtml