What is the Difference Between Free Chlorine and Total Chlorine?

With regards to pools and spas, it is essential to keep up with appropriate chlorine levels in the water. Chlorine is utilized to kill off microbes and different microorganisms that can pollute the water, which likewise assists with keeping a pH balance in the water that is safe for swimmers. But chlorine comes in two forms - free chlorine and total chlorine. What is the difference between free chlorine and total chlorine? In this article, we will delve into the differences between free chlorine and total chlorine, and how to measure each type of chlorine accurately. 

What is free chlorine?

Free chlorine is known as free residual chlorine in the form of hypochlorous acid, hypochlorite ion, or dissolved monomeric chlorine. Free available chlorine and free chlorine residual are other names for it. What is the role of free chlorine?

During the process of producing water, the waterworks plant will add an appropriate quantity of preparations containing chlorine to eliminate bacteria and other microorganisms from the water. The chlorine-containing preparations will interact with the water's bacteria, microorganisms, and organic and inorganic matter following their addition to the water. Free chlorine can keep killing microorganisms. It likewise keeps water from being once again debased. In this manner, the degree of free chlorine can mirror how much sanitizer is and the capacity of water to clean microorganisms.

What is total chlorine?

Total chlorine is the total amount of all chlorides in water, including naturally occurring chlorides and chlorine added by disinfectants. Disinfectants, such as chlorine gas and sodium hypochlorite, are often added during water treatment to destroy bacteria and pathogens. These sanitizers respond with natural matter and microorganisms in the water to frame chlorides. Therefore, the total chlorine content can mirror the aggregate sum of chlorides in the water, including those created by sanitizer augmentations.

What is the difference between free chlorine and total chlorine detection methods?

1.Detection methods for free chlorine:

(1) DPD method

(2) Colorimetric method

(3) Electrode method

Among them, the DPD method is the simplest with more accurate results, and thus is the most commonly used in the detection of free chlorine.

2.Detection methods for total chlorine:

(1) Silver Chloride Method

(2) Electrode method

(3) High-temperature oxidation method

What is the difference between free chlorine and total chlorine of the treatment method?

Chlorine has been used for decades to disinfect water to eliminate waterborne diseases. It is very effective in eliminating pathogens and diseases. It is widely used because it is cheap and easy to control and monitor. Chlorine easily maintains residual levels in water distribution and continues to protect drinking water supplies from bacterial growth. This is why chlorine is considered one of the best disinfectants. Regardless of its viability and moderation in cleaning water supplies, chlorination has its very own few issues. Here are some common treatment methods for free chlorine and total chlorine. 

1.Treatment methods for free chlorine:

(1)Aeration method. 

This sort of strategy fundamentally uses air to circulate air through wastewater containing free chlorine. On the one hand, some of the undissolved compounds can be blown off into the air to reduce their concentration in the water. On the other hand, the oxygen in the air can be utilized to lessen all the disintegrated free chlorine to stable Cl- before subsequent treatment. 

(2)Chemical oxidation method. 

This type of method is mainly through the addition of chemicals with strong reducing properties, such as Na2SO3, Na2S2O3, Na2S reagent, etc.

2.Treatment methods for total chlorine:

Different from the removal of free chlorine, we can remove total chlorine in daily life. Some common methods are as follows.

(1)Still standing method

A simple method for eliminating chlorine is to allow the water to sit in an open holder for a couple of hours before use.

(2)Heating

Heating or boiling the water can also remove chlorine from the water. 

(3)Absorption

Activated carbon can adsorb the chlorine ions in the water. 

(4)Using water purification equipment

You can buy special water purification equipment for rapid dechlorination. With access to tap water, you can directly dechlorinate and filter impurities.

Conclusion

After analyzing the difference between free chlorine and total chlorine, we can learn that free chlorine is the type of chlorine that is actively disinfecting the water, while total chlorine is the amount of chlorine present in the water. It means quite a bit to measure the two kinds of chlorine to guarantee that the water is safe for individual use.