pH Control
We can also inject CO2 to lower pH.
- Carbon dioxide is a gas which produces carbonic acid, a weak acid, when dissolved in water.
- Carbonic acid is a mild acid present in water as H+ and HCO3, which are highly reactive ions.
- The ions react immediately with alkalis such as caustic soda, sodium carbonate, and dissolved lime, turning them into neutral carbonates and bicarbonate salts.
CO2 + H2O » H2CO3
H2CO3 + 2NaOH » Na2CO3 + 2H2O
H2CO3 + Na2CO3 » 2NaHCO3
One thing to note about using CO2 gas is it is an consumable, unlike ozone and oxygen that is produced on location.
Benefits of using CO2 gas to lower pH:
- Safe to use
- Accuracy of regulation
- Low maintenance system
- Flexibility
- Safe for the environment