Read on as you are certain to learn just how effective Chlorine Dioxide can be as an innovative solution to bacterial and microbial management. All of our products are prepared for both residential and commercial applications such as Air Treatment, Food & Beverage, High School & College, Hospitality, Medical, Senior Living. Click here for all of our disinfecting/sanitizing products.
With expertise across many industries, our company is positioned to help solve nearly any challenge. Contact us to discuss your opportunity, and thank you for taking the time to visit our site.
Nearly 200 years ago Sir Humphrey Day invented chlorine dioxide. The gas was obtained by way of a chemical reaction of sulphuric acid and potassium chlorate. Chemist later found that CIO2 and CI2 (Chlorine) have ‘some’ properties in common, but are also remarkable different. CIO2 is a yellowish-green gas with a chlorine smell, which in its concentrated form is irritating to the eyes, nose and throat. However, both materials are COMPLETELY different when it comes to their physical and chemical properties, regardless of the fact that they both have a chlorine atom in their molecular structure.
Differences in Water Between Chlorine Dioxide and Chlorine
The single biggest difference between CLO2 (Chlorine Dioxide) and CL2 (Chlorine) is the way they behave in water. Chlorine dioxide is 10 x more soluble in water than chlorine. Chlorine dioxide also does not hydrolise in a solution. This means that it behaves like a “true” dissolved gas and maintains its oxidation and biocide capabilities within wide pH range from 4 to 10. Chlorine on the other hand disassociates in water and forms hypochlorine acid and bichlorine acid. Hypochlorine acid then becomes the primary biocide, but in case of a higher pH is transformed into the hypochlorination. This hypochlorination has as a biocide only 1/20 to 1/300 of the strength of hypochlorine acid itself. Therefore chlorine is only an effective biocide in case of controlled pH (+- 7,4 – 7,6). The high solubility of chlorine dioxide not only occurs in water, but also in many organic substances such as; oils, solvents, etc. And keep in mind that it is as efficient at pH 4 as with pH 10.
Molecular properties / Oxidation
Chlorine dioxide is a very small, volatile and very strong molecule that disinfects by means of oxidation and not by means of substitution like chlorine. The following statement is VERY IMPORTANT when defining differences between the two compounds. The oxidation strength of chlorine dioxide is lower than the oxidation strength of chlorine, but the oxidation capacity is greater than 2X times higher. Oxidation strength describes how strong an oxidant reacts with oxidizable material. The stronger the oxidation strength, the higher the amount of oxidizable materials with which the reaction takes place. Chlorine dioxide by comparison, is much weaker, so the benefit to the end user means far less reaction to materials it is being used with . It has a lower oxidation potential than ozone, chlorine gas and hypo chlorine acid. HOWEVER : the oxidation capacity depends on the number of electrons that are being exchanged during an oxidation-reduction reaction. Higher oxidation capacity = more effective biocidal effectiveness, or in other words, higher bacterial kill rates in shorter contact times.
The chlorine atom in chlorine dioxide has an oxidation level +4. Because of this chlorine dioxide can take on five electrons during the process of reduction to chloride. When we compare to chlorine, chlorine dioxide disposes of 263 % “available chlorine”. This is 2.5 times the oxidation capacity of chlorine. Because of this lower oxidation strength chlorine dioxide is far more selective than chlorine. Chlorine dioxide does not chlorinate, to create a chlorine compound.
IMPORTANT: Chlorine is a stronger oxidant which WILL REACT with a larger number of chemicals, including ammonium. These properties REDUCE the effectiveness of chlorine as biocide. Because chlorine dioxide has a higher oxidation capacity than ozone or chlorine, less chlorine dioxide is required for a residual concentration in the case of disinfection.
Oxidation Capacity Continued
We now know that chlorine dioxide has an oxidation capacity 2x as strong as that of chlorine, and the oxidation strength on the other hand remains lower. It is because of this lower oxidation strength that chlorine dioxide is more selective than chlorine and will not lose its capacity as an excellent biocide. In contrast, because chlorine is a strong oxidizer it reacts with more chemicals, which breaks down its potential to be an effective biocide.
Properties of Chlorine Dioxide
Thanks to the specific physical and chemical properties of chlorine dioxide, it is ideal for controlling microbiological contamination wherever it may occur; Fluid Decontamination, Surface Decontamination, Spatial Decontamination. Chlorine dioxide already has a rich history as an efficient biocide as well as a fluid or surface disinfectant. It also has very broad scope applications in areas such as; Drinking-Water Disinfection, Waste Water treatment, Agriculture and Horticulture, Cooling tower and Cooling water systems.
Chlorine dioxide behaves as a “true” gas in water, and other solutions. This can be compared to how CO2 behaves when it is dissolved in a can of soda. Chlorine Dioxide keeps its original chemical structure and properties in a solution. This is a very important quality not only for efficiency, but also for safety when used. This means that chlorine dioxide stays equally efficient in a liquid solution as it does in its gaseous form. Chlorine by contrast is an acid gas which dissociates in a hypo chlorine acid and a bi chlorine acid. From a safer perspective chlorine dioxide does not chlorinate any organic material. There are aslo no trihalomethanes, or other possible carcinogenic compounds generated as there are in the case of chlorine. Chlorine dioxide can be kept safely in solution after generation until it is used.
Chlorine dioxide is strongly soluble in water and in different organic substances. This strong solubility allows chlorine dioxide to blast its way through some substances that protect particular micro organisms. This is not the case of many other biocides such as chlorine/bleach. A very good example of this is the fact that many bacteria in water, particularly those with sporulating properties, are protected by a poly saccharide film, otherwise known as BIOFILM. Many other biocides including chlorine cannot penetrate such films because of its ionic properties in water.
How Chlorine Dioxide Penetrates Biofilm
Chlorine dioxide penetrates these protective layers and kills the underlying harmful micro organisms. This quality of chlorine dioxide make it an ideal choice to eliminate BIO FILM, especially in drinking-water pipes and cooling towers. This special trait of chlorine dioxide also makes it an obvious means as a disinfectant for the removal of many different pathogenic organisms (Legionella). Chlorine dioxide also does not have any corrosive effects, is not pH or temperature dependent, and is insensitive to the hardness of water. In addition, in the case of user concentrations, and in contrast to many chlorine products, it does not cause any influence on taste or smell of the water. When used in cooling towers as a water disinfectant, chlorine dioxide has additional advantages because the efficiency is increased and the energy consumption is being reduced by the removal of biofilm. In addition, chlorine dioxide can also be used in the oil industry where it penetrates hydrocarbon layers and thus can oxidize contamination and bacteria that are protected by these above-mentioned structures.
Less harmful side effects
Aside from its biocidal effectiveness, there are enormous time, cost, and health benefits of using chlorine dioxide. When used in treatment, chlorine dioxide does not need any special post treatment, nor does it have to be wiped/washed down from surfaces in cases of surface decontamination. Because of its very ‘active’ nature, Chlorine dioxide is degradable in a very natural way. For example, a small concentration of 750 ppm chlorine dioxide will disappear completely, without any post treatment, within a couple of hours. And will not leave any harmful, or visible residue on the treated surfaces. In the case of every chlorine dioxide molecule, it will degrade into simple, non irritating sodium salt. It is a combination of these positive properties that compelled the USEPA to use chlorine dioxide in government buildings to treat for anthrax in 2001.
CIO2 an effective biocide
The characteristic property of CIO2 to react through oxidation and not via substitution, turns this product into an excellent alternative for chlorine, especially when it comes to drinking-water disinfection. There is no forming of possible carcinogen halogenized by-products in the case of CIO2. CIO2 will neither form significant amounts of aldehydes, ketons, keton acids, etc.with organic components in water, which is the case with OZONE. (O3). The reaction of CIO2 with micro-organisms or other organic materials takes place in two steps. During the first phase of the reaction the CIO2 molecule takes on one electron and the chlorietion (CIO2-) is formed. During the second phase CIO2 takes on 4 more electrons and we get chloride (Cl-). The elimination mechanism of CIO2 is still not completely clear. Although it is sure that CIO2 kills microbes by penetrating the cell wall and prevents the essential protein formation. CIO2 is also more effective against viruses than chlorine and ozone. CIO2 is effective too against protozoa, growing profusely in the water, like e.g. Giardia, Lambia and Crytosporidium. They cause the respective giardiasis and cryptosporidiosis.