CO2 
       a poison that must be 
      removed
 
 
   
 
  
   
   
 
 
  
  
 
     
       
 
 
 
 
 
 
 Design an air 
      filtering system for a submarine? This filter must remove odours and 
      carbon dioxide from the air. Conduct some experiments to see how best to 
      remove odours.  Try using common 
      household baking powder and discuss your 
      results. Indicate where the air 
      is channelled and what reactions take place. For long space  voyages discuss how best to 
      provide oxygen and remove carbon 
      dioxide? Carbon dioxide is 
      toxic to the astronauts. If its concentration is allowed to increase it 
      will be fatal. The Orbiter has special air filters containing lithium 
      hydroxide. The air is passed through the filters and any carbon dioxide 
      present reacts with the  
      lithium hydroxide to produce a harmless solid substance called 
      lithium carbonate. Just like the movie above calcium hydroxide (lime 
      water) works in a similar way to lithium hydroxide. As carbon dioxide is 
      bubbled through lime water solid calcium carbonate is formed. Calcium 
      carbonate is non toxic, in fact it is the substance the normal chalk is 
      made up of.  The filtered air has 
      no carbon dioxide, all the carbon dioxide has reacted to form lithium 
      carbonate. Lithium carbonate stays in the filters as a solid 
      substance. When 
      CO2 is bubbled through water containing calcium hydroxide (lime 
      water) a solid white substance is formed. This white solid has the 
      chemical name calcium 
carbonate.