What Is Monochloramine?
Monochloramine, often simply referred to as chloramine, is a compound formed when one hydrogen atom in ammonia (NH3) is replaced by a chlorine atom. It’s produced through the reaction of sodium hypochlorite and ammonia in alkaline conditions, resulting in a clear, colorless liquid useful in various disinfection processes.
Uses of Monochloramines
The main uses of monochloramine include the following:
1. Drinking Water Treatment
Monochloramine is used in drinking water treatment to kill bacteria, viruses, and microorganisms. They are also used at wastewater treatment facilities.
When ammonia and chlorine are injected simultaneously into the water in a 1:3 ratio, they produce monochloramine NH2Cl and dichloramine NHCl2, which gradually liberate hypochlorous acid HClO to manifest their bactericidal action. Although the sterilizing power is weak, it is known to have a residual effect in water and is called the chloramine method.
2. Treatment of Swimming Pool Water and Bathtub Water
In pool and spa water treatment, monochloramine provides disinfection and preserves water quality. Monochloramine reacts with chlorine to form a stable disinfectant that inhibits the growth of microorganisms in the water.
3. Cooling Water Treatment
Monochloramine prevents the growth of microorganisms in cooling water used in industrial processes and air conditioning systems.
4. Disinfection of Fire Fighting Equipment
Monochloramine is used to disinfect firefighting equipment such as hoses, water tanks, and fountains.
Properties of Monochloramines
Monochloramine is a stable, chlorinated ammonia derivative, well soluble in water and stable under neutral to slightly acidic conditions. It’s used for its disinfectant properties, breaking down into chloride ions and nitrogen upon reaction with chlorine, without the harsh chlorine odor or the formation of harmful by-products.
Other Information on Monochloramines
Concentration of Monochloramines
The effective concentration for monochloramine disinfection is around 3 mg/mL.