Question of the Day: Chlorine Species

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Taxonomy

• Industrial Wastewater Treatment
• Industrial Water Treatment
• Chlorination
• Laboratory Testing

5 Answers

1. I'd add stabilized chlorine/bromine as part of combined chlorine. These are hydantoin and cyanuric products.

2. Listen to 8:18

   http://scalinguph2o.com/2018/10/26/057-pinks-and-blues/

   "Free is what is available right now to do a quick kill and start to sterilize or sanitize the system. Total is the addition of free and combined Chlorine - combine with some organics (bromine for example" It is important to know what the total number is for both. If way more combined Chlorine than free this may or may not be a problem depending on the application.  

3. Agreed with respect to free chlorine pertaining to HOCl (and OCl- ion) in solution however it gets there.  Agreed also with respect to various chloramines, portraying combined chlorine species.  Total chlorine is the sum total of chloramines, free chlorine, and also any other free halogen in the system.  For example, I use a bromine release agent in cooling water due to selection of a higher pH program where free chlorine is not as effective.  The addition of this bromine results in a better kill at the higher pH, and also results in a "free chlorine" residual that would not normally be present given our source water being chloraminated.

4. Dennis is correct, Free is HOCl and HCL, combine is the mono, di and tri chloramines and any other available organics

5. Free chlorine is the measure of the amount of hypochlorous acid (HOCl) formed by the addition of chlorine to water. Combined chlorine is the measure of the amount of chloramines formed when chlorine is added to water containing ammonia. Total chlorine is the sum of the free + combined chlorine.