The impact of CO2 gas on Demineralized Water quality

Demineralized water production is a very sophisticated and costly process. The demineralized or ultra pure water in DM or Condensate tanks becomes in contact with atmospheric air through the vent nozzle during emptying of the tanks. Due to the reaction of demineralized water with CO2 gas, the water changes its chemical properties to deionized or “aggressive” water.

During the production of demineralized water, CO2 (carbon dioxide) is removed from the content of the water. In case there is contact between the air and CO2 again, the same occurs and it dissolves back into the water. This impacts the quality of demineralized water and changes the quality parameters of demineralized water. The first one to be affected is the pH parameter of water starts to fluctuate.

CO2 (Carbon dioxide) dissolves into the water and ionizes the water. During the slow chemical reaction CO₂ turns to carbonic acid (H₂CO₃) in the form of weak acid.

The following reaction is showing this process CO₂ + H₂O → H₂CO₃.

Carbonic acid creates hydronium (H₃O⁺) and bicarbonate (HCO₃⁻) ions with water reversing the equilibrium of the water. The following reaction is showing this process H₂CO₃ + H₂O → HCO₃⁻ + H₃O⁺.

This chemical reaction explains why deionized water comes into contact with atmospheric carbon dioxide, its absorption of the gas produces carbonic acid, which can reduce the water's pH to as little as 5.5. For this reason, the pH reading of demineralized water must be 7 so that the quality of demineralized or pure water may be kept high.

The atmospheric air contains 400 ppm of carbon dioxide (CO2). In industrial areas this value can be even bigger. All demineralized or pure water tanks with atmospheric vent nozzles, are subject to CO2 affecting the pH and conductivity values of the storage water.

Moremex Tank CO2 (carbon dioxide) absorbers/CO2 tank breather filters

Moremex Tank CO2 absorbers allow to sustain the desired pH and conductivity of demineralized water. It can be fitted on storage tanks or installed on the ground near the tank by connecting to the tank by an air duct. The highly efficient and long-lasting filter media in the absorber blocks CO2 from penetrating the tank. The Moremex Tank CO2 absorber/CO2 tank breather filter is also equipped with a color indicator that allows you to monitor the filter saturation by CO2 and tells you when to change the cartridges with media at the right time. The Moremex Tank CO2 absorber can be equipped with pressure and vacuum relief valves and differential pressure gauge switches. Dust particles and sand which may come from the outside are also captured by the filters, preventing contamination entering the tank.

The dimensions and design of the Moremex CO2 absorber/CO2 tank breather filter units are based on data sheets of the storage tanks, so unnecessary costs are avoided with an exact amount of units produced for each project.