Potassium Superoxide

Potassium superoxide is the chemical compound with the formula KO₂. This rare salt of the superoxide ion is produced by burning molten potassium in pure oxygen. Potassium superoxide is used as an oxidizing agent in industrial chemistry, as a CO₂ scrubber, H₂O dehumidifier and O₂ generator in rebreathers, spacecraft, submarines and spacesuit life support systems.

Important reactions:

4 KO₂ + 2 H₂O → 4 KOH + 3 O₂

2 KOH + CO₂ → K₂CO₃ + H₂O

K₂CO₃ + CO₂ + H₂O → 2 KHCO₃

4 KO₂ + 2 CO₂ → 2 K₂CO₃ + 3 O₂

The Russian Space Agency has had success using potassium superoxide in chemical oxygen generators for its spacesuits and Soyuz spacecraft. KO₂ has also been utilized in canisters for rebreathers for fire fighting and mine rescue work, but had limited use in scuba rebreathers because of its dangerously explosive reaction with water. The theoretical capacity of KO₂ is the absorption of 0.309 kg CO₂ per kg of absorbent while 0.338 kg O₂ are generated per kg of absorbent. The human body though will produce more CO₂ than oxygen absorbed, thus a device or absorbent specifically for CO₂ scrubbing may also be required.