What is pH-Raising Media? Mechanism of Action in Water Treatment

1. What is pH-Raising Media?

pH-raising media are water filtration materials used to increase the pH of acidic water (pH < 7). The most commonly used types of pH-raising media in water treatment include:
 

• Corosex (MgO – Magnesium Oxide): Rapid pH increase, suitable for very low-pH water.

• Calcite (CaCO₃ – Calcium Carbonate): Provides stable pH adjustment, ideal for slightly acidic water.

• Dolomite (CaMg(CO₃)₂ – Calcium Magnesium Carbonate): Raises pH while adding essential minerals to the water.

2. Mechanism of Action of pH-Raising Media in Water Treatment

pH-raising media work by neutralizing acidic water through chemical reactions between the acidic water and the active components of the media. The mechanism of each type is as follows:
 

Calcite (CaCO₃)

• When water passes through Calcite media, CaCO₃ slowly dissolves into the water, increasing pH.
   

• Chemical reaction:
   

  CaCO3+H2CO3→Ca(HCO3)2

  (Calcium Carbonate + Carbonic Acid → Calcium Bicarbonate)
   

• Calcite dissolves gradually, providing a stable pH increase.
   

Corosex (MgO)

• Corosex contains Magnesium Oxide (MgO), which reacts with acidic water more effectively than Calcite.
   

• Chemical reaction:
   

  MgO+H2O→Mg(OH)2

  (Magnesium Oxide + Water → Magnesium Hydroxide)
   

• Magnesium Hydroxide acts as a strong base, neutralizing acidity faster than Calcite.
   

Dolomite (CaMg(CO₃)₂)

• Dolomite consists of both Calcium Carbonate (CaCO₃) and Magnesium Carbonate (MgCO₃), allowing it to raise pH while adding minerals to the water.

• When exposed to acidic water, CaMg(CO₃)₂ gradually dissolves, releasing Ca²⁺ and Mg²⁺ ions, ensuring a more stable pH balance.

3. Advantages of Using pH-Raising Media in Water Treatment

• Safe and non-toxic: Natural minerals, free from harmful chemicals.

• Easy to use: Can be placed in filter tanks or filtration columns without the need for chemical dosing systems.

• Improves water quality: Helps maintain an appropriate pH level, reducing water corrosiveness.

• Protects piping and equipment: Low-pH water can corrode metal, damaging pipelines and machinery.

4. When Should You Use pH-Raising Media?

• When the incoming water has a pH below 6.5, causing strong acidity and pipe corrosion.

• When water contains high CO₂ levels, leading to low pH and poor water quality.

• When using well water with low pH, requiring pH adjustment to meet drinking water standards.

5. How to Use pH-Raising Media Effectively

• Use in filtration columns: Place the pH-raising media in a pre-treatment filter before the main treatment system.

• Combine different media types: Calcite is often used together with Corosex for better pH adjustment.

• Regular replacement: Media depletes over time, so it should be replenished or replaced every 6–12 months.

6. Conclusion

pH-raising media are safe and effective materials for adjusting water pH to an optimal level.

Choosing the right media type helps protect pipelines and equipment while ensuring high water quality.
 

Looking for a reliable pH adjustment solution? Contact REECHEM today for expert advice on suitable products!
 

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