How Chlorine Dioxide Works

   (PREFACE: While the author is not a chemist he has worked extensively for years with the manufacture of sodium chlorite solutions, and chlorine dioxide solutions for consumer use as well as industrial use. He is familiar with  the handling and characteristics of the chemicals mentioned in this article. The author has also talked with 1000's of people who have used chlorine dioxide for a variety of applications. While this article is meant to be informative about the nature and characteristics of Chlorine Dioxide, this article will not address any unapproved or medicinal use of this product.

The process through which Chlorine Dioxide is generated and used is approved for many applications that can also be applied to common household uses.

 In this article I will try to answer some of the most common questions and misconceptions about  Sodium Chlorite and Chlorine Dioxide, and tackle some of the most often debated statements made about this useful chemical.) 

CHLORINE DIOXIDE: What it Is and How it Works.

  In the first part of this series we will look at the actual material that Chlorine DIoxide is made from, Sodium Chlorite as well the Chlorine Dioxide it produces.

Chlorine Dioxide is produced from dropping the pH of a solution made from Sodium Chlorite and Distilled water.

 There will be some inert salts that were used as buffers in the raw material, which is usually a technical grade of anhydrous sodium chlorite. This may be in powder or flake form, depending on the manufacturer.

 The amount and type of these inert ingredients can vary depending on the raw material used but will generally not exceed 20% of the Raw Sodium Chlorite Powder.

 Typical inert ingredients found in the raw material are Sodium Sulfate, Sodium Carbonate, and Sodium Chloride (salt).

  There may be traces of Sodium Hydroxide, and Sodium Chlorate left over from the manufacturing process of the raw material.  Industrial Grades for non EPA approved uses may contain traces of lead, mercury, and arsenic.

 Sodium Chlorite is not a natural product although some websites would like you to believe it is.. It is a manufactured chemical not found in nature. Sodium Chlorite itself has no real viable uses.

   It is manufactured solely as a precursor to the generation of Chlorine Dioxide. (CLO2). It is most often manufactured by what is known as the Hooker R2 Process.

Sodium Chlorate (NaClO3) is mixed with Sodium Chloride (NaCl). Sulfuric Acid (H2SO4) is added to this, and chlorine dioxide, as well as chlorine gas is formed. The gases are separated by absorbing the soluble chlorine dioxide in chilled water towers.

 Sodium Hydroxide is used as well as. Hydrogen peroxide to form the Sodium Chlorite, and remove Sodium Chlorate . There has been an article circulating for years on eHow and Yahoo answers, about making sodium chlorite from a brine solution through electrolysis, that can be done at home.  This actually produces toxic sodium chlorate and should not be attempted. There is no simple method to produce Sodium Chlorite at home.

Anhydrous Sodium Chlorite and Sodium Chlorite Solution can be safely shipped as opposed to Chlorine Dioxide Gas which can not be shipped safely, or economically. Once on site, the Sodium Chlorite  is put into solution. This solution has a high pH, usually 12 +. An acid is added to lower the pH and Chlorine Dioxide is produced.

Chlorine Dioxide

 Chlorine Dioxide is the product of lowering the pH of a sodium chlorite solution with an approved acid.. It exists as a greenish gas at normal temperatures. The concentrated gas being formed in the mixed solution gives it an amber aspect.

  Chlorine Dioxide is a small, volatile molecule, that reacts with other substances by means of oxidation.

 Depending on the use, and how it is formed, it is an FDA and EPA approved pesticide that can be used in food service, municipal water, mold treatment, odor treatment, medical use,  mouthwashes, toothpastes, eyecare, and in personal water treatment products, among other applications.   It is considered to be a more "Earth-Friendly" alternative to many chlorine applications.

Isn't Chlorine Dioxide the same as Bleach?

 Bleach is a relative term. Many chemicals including oxidizers such as Hydrogen Peroxide (H2O2), can be considered a bleach.  Bleaching means they remove color, and yes, Chlorine Dioxide will remove color, like most oxidizers,
 One industrial use for Chlorine Dioxide is as a bleach for wood pulp, (used in conjunction with sodium hypochlorite), and as a bleach for flour in some countries including the US. The reason it it used in the paper mills is also because of the fact the chlorine dioxide gas prohibits the growth of bio-film as well as for it's bleaching properties.
 

When people say bleach they usually mean Sodium Hypochlorite (ClO) (common household bleach), 

The real question is: Is chlorine dioxide(ClO2) the same as chlorine (Cl) or sodium hypochlorite (ClO) . The short answer is no.

 However, before we look at why they are so different, let's look at why people tend to equate them

 It does smell a lot like chlorine. It can also irritate the eyes and respiratory system if the concentration is too strong.

 It disinfects, and kills micro-organisms.

 Then of course the name....   Chlorine Dioxide..... and yes, Chlorine dioxide does have a Chlorine atom.

 But.... So does salt, in fact the only elemental difference between table salt, sodium chlorite, and common bleach is the number of oxygen atoms attached to the molecule.

1 Sodium Atom + 1 Chlorine Atom                                    =   NaCl  (Common Salt Molecule)

 1 Sodium Atom + (1 Chlorine Atom +1 Oxygen Atom)    =  NaClO  Sodium Hypochlorite Molecule (Common Bleach)

 1 Sodium Atom + (1 Chlorine Atom + 2 Oxygen Atoms) =  NaClO2  Sodium Chlorite Molecule

 1 Sodium Atom + (1 Chlorine Atom + 3 Oxygen Atoms) =  NaClO3  Sodium Chlorate Molecule

(Toxic, Used to make other chlorine compounds. Used as a pesticide and defoiliant,)

 1 Sodium Atom + (1 Chlorine Atom + 4 Oxygen Atoms) =  NaClO4  Sodium Perchlorate Molecule

(Non reactive electrolyte often used in molecular science for DNA extraction and hybridization.)

  This is to demonstrate the difference a single atom can make in a molecule.

 Pure sodium would ignite in your mouth, and pure chlorine has been used as a chemical weapon, yet table salt, a necessary mineral, is just a combination of the two.
In fact these 2 elements, Sodium and Chlorine make up about .2% of your total body chemistry each.
 
 

Chlorine Dioxide vs Chlorine: What's the difference?

 This is the real focus of the issue, and the answer is really pretty simple. While both kill pathogens well....  Chlorine Dioxide does it differently, and more efficiently, without creating toxic byproducts. Chlorine Dioxide kills by oxidation, whereas Chlorine kills by substitution, (in this case called chlorination).
 
 Chlorine Dioxide has a lower oxidation strength than chlorine, but more than twice the oxidative capacity.  Reduction/Oxidation Strength or "Redox" is a measure of how strongly an oxidizer reacts with with organic material, the higher the redox potential, the more substances the oxidizer will react with. Chlorine Dioxide has a lower redox potential than ozone, chlorine, or hypochlorus acid.  Because of this lower redox potential, Chlorine DIoxide is more selective in what it reacts to.
 Typically Chlorine DIoxide will only react with compounds that have active carbon bonds, sulfides, cyanides, and compounds with reduced iron or manganese. Chlorine has a higher redox, and will react with a wider range of compounds, including ammonia.  Because of this difference Chlorine DIoxide does not create toxic by products like chlorine does. This is why Chlorine is limited as a biocide in it's overall effectiveness as opposed to Chlorine DIoxide.
 
 The higher oxidation capacity means that Chlorine Dioxide will remove 5 electrons from the target, whereas chlorine can only remove 2.  Chlorine will bind to a pathogen, and other chemicals and compunds that may be present.  Chlorine DIoxide being more selective, will not  bind with other compounds.  Because of this capacity, Chlorine Dioxide is more efficient than Chlorine, Ozone, or Hypochlorus Acid when used as a disinfectant.
 After the reaction is complete, Chlorine Dioxide reverts to chloride (salt). Chlorine forms Tri-halomathanes from reaction to ammonia, plus other byproducts from other chemicals and compounds as may be present.
 

How Chlorine Dioxide works on Pathogens

Chlorine dioxide kills pathogens by stopping  protein formation.  Viruses and Bacteria are killed by different methods.  

• Bacteria is killed through the oxidation process mentioned above.  The chloride dioxide steals five electrons from the amino acid of the targeted pathogen.  The amino acid becomes unable to produce the proteins necessary to maintaining the cell wall. The cell wall collapses and the pathogen dies. 
• Viruses are killed by the reaction of Chlorine DIoxide to peptone. Peptone is vital to the protein formation of the virus. It becomes unable to function, thus "starving" the virus.
• Pathogens can't build a resistance to Chlorine Dioxide. Even so called "Superbugs" that are resistant to antibiotics have no defense. Chlorine dioxide attacks these pathogens at the molecular level, not through poisoning.

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The History of Chlorine Dioxide.

 Chlorine Dioxide was discovered by Sir Humphrey Davy in 1844. The British chemist combined potassium chlorite with sulfuric acid. It will soon be discovered that this green gas would be a more effective disinfectant than chlorine.

  By the 1930's Chlorine dioxide was being used more frequently for disinfecting areas. Because of it's gaseous form, it filled spaces evenly. The volitile gas was impossible to ship safely, so Sodium Chlorite began to manufactured as a relatively safe precursor chemical, and the industries using chlorine dioxide would then generate the gas onsite as needed. Because of Chlorine Dioxide's solubility in water, it starts being used as a water treatment.

  In 1944, Chlorine Dioxide was used  by the City of Niagra New York, to control odor and remove phenols from the river water used as the municipal supply to good effect. The city soon changes to Chlorine Dioxide exclusively. The water is cleaner, tastes better, and has no odor compared to the use of chlorine.

  In 1956 Brussels Belgium makes the switch from Chlorine to Chlorine dioxide for it's municipal water system.

 It is discovered that Chlorine dioxide will destroy algae biofilm, a feat which Chlorine could not accomplish.

 Through the 1960's more cities and swimming pools start to change to Chlorine Dioxide.

 In 1967 The United States Environmental Protection Agency (E.P.A)  registered an aqueous form of Chlorine Dioxide to be used as a sanitizer and disinfectant. Chlorine DIoxide starts being used commercially on fruit and produce  as a sanitizer.

  In the 70's and 80's The EPA began reccomending Chlorine DIoxide over Chlorine for water treatment and other applications. This was due to the fact that because of their different chemical properties, Chlorine Dioxide was more efficient, and did not produce toxic trihalomethanes like chlorine.

 In 1988 the EPA registered Chlorine Dioxide as a sterilizer approved for hospitals, laboratories, and healthcare facilities

 In 2001 FEMA and other government agencies use Chlorine Dioxide to to decontaminate buildings contaminated with Anthrax  The Chlorine Dioxide was completely effective against the tiny Anthrax Spores. The buildings, walls and furnishings suffered no damage from the treatment.

 In 2005 FEMA again uses Chlorine DIoxide. This time to eradicate mold from damage caused by Hurricane Katrina. A restaurant in New Orleans was able to re-open after being treated for just 12 hours without major repair.

 In 2006, a man named Jim Humble releases a book called "Breakthrough - The Miracle Mineral Supplement of the 21st Century" in which he details that in desperation, he used the sodium chlorite solution in a chlorine dioxide water treatment product in an attempt to alleviate a man's severe malaria symptoms. Jim Humble claims that the man was in fact cured. Jim went on recount many other illnesses he has discovered that chlorine dioxide could be used for. He develops MMS which is a system to generate small amounts of chlorine dioxide at home.

In 2010  the United States Food and Drug Administration issue a warning on using  MMS according to the JIm Humble protocols. They label it as industrial bleach.  

In the mean time they will have approved the use of Chlorine Dioxide for use in mouthwashes, toothpastes, and as a food service disinfectant among other uses, citing it as being a better alternative than chlorine.

The products, uses, and applications for Chlorine DIoxide continue to grow. More and more mainstream health and home related products are using chlorine dioxide.

Chlorine Dioxide Biocidal Spectrum

As mentioned above, Chlorine Dioxide in different products has been registered since 1988 as a sterlizer .

 The  EPA definifition of a sterlizer is the ability "to destroy or eliminate all forms of microbial life including fungi, viruses, and  all forms of bacteria and their spores," 

More specific tests have been done that prove Chlorine Dioxide's ability to destroy the following:

Keep in mind this is not the full spectrum, but specific tests done against many of the most common pathogens. Included in this list are MRSA,  HIV, E.Coli, Staph, Anthrax, Salmonella, Parvo, Aspergillus, Candida, and many other pathogens that most people will have contact with through thier lives. Chlorine Dioxide when used as a water and surface treatment, vegetable rinse, and environmental cleaner, can help keep your home a cleaner, safer place than using chlorine based products.