But the tricky part is understanding that there is no such thing as chlorine dioxide, it is derived from a chemical process.
It is only since the late 70's that sodium chlorite or "stabilized chlorine dioxide" (I explain it further down) became available and it's uses investigated.
In the late 90's in Australia I started a push to be open about our Industry, products and their uses.
This was because some suppliers were claiming their product was better than others when predominately all used NaClO2 (Sodium Chlorite) as the precursor chemical and an acid.
Arguments that were based on facts from both sides that were correct, it's just the layman understanding of what was being said was just like Miracle-Mineral-Supplement
supporters, they did not understand, and some companies seen this as an opportunity to make a quick dollar, just like Miracle-Mineral-Supplement
I wanted it said publicly that there are two different technologies we are dealing with, that of sodium chlorite to produce chlorine dioxide and that of sodium chlorite to produce ASC (Acidified Sodium Chlorite).
Hence ASC and CLo2 Technologies.
I explain these under sodium chlorite. Simply if someone was using sodium chlorite and citric from one supplier the other would show how you could use their product at 1/10 of the sodium chlorite "claiming better performance and product" and Hydrochloric acid and prove the same release of free ClO2.
This was because we realised different acids other than HcL gave a different ClO2 release and a chlorous acid residual.
The free acid, chlorous acid, HClO2, is only stable at low concentrations. Since it cannot be concentrated, it is not a commercial product..I explain more under sodium chlorite
O.K I'll try to keep it in layman's terms.
common salt, (also used to make chlorine)
oxidation state −1 +1 +3 +5 +7
anion name chloride hypochlorite chlorite chlorate perchlorate
formula Cl− ClO− ClO2− ClO3− ClO4−
structure chloride ion hypochlorite ion chlorite ion chlorate ion perchlorate ion
Industrially, sodium chlorate is synthesised from the electrolysis of hot sodium chloride solution in a mixed electrode tank:
It can also be synthesised by passing chlorine gas to a hot sodium hydroxide solution. It is then purified by crystallization.
Over 95% of the chlorine dioxide produced in the world today is made from sodium chlorate and is used for pulp bleaching. It is produced with high efficiency by reducing sodium chlorate in a strong acid solution with a suitable reducing agent such as hydrochloric acid and sulfur dioxide.
Since 1999 a growing proportion of the chlorine dioxide made globally for water treatment and other small scale applications has been made using the chlorate, hydrogen peroxide and sulfuric acid method which can produce a chlorine free product at high efficiency.
Sodium chlorite is derived indirectly from sodium chlorate, NaClO3. First, the explosively unstable gas chlorine dioxide, ClO2 is produced by reducing sodium chlorate in a strong acid solution with a suitable reducing agent (for example, sodium chloride, sulfur dioxide, or hydrochloric acid). The chlorine dioxide is then absorbed into an alkaline solution and reduced with hydrogen peroxide, H2O2 (Hydrogen-Peroxid)
yielding sodium chlorite. Added to this are anti fire retardants and anti corrosive properties.
Sodium chlorite which is a chemical compound and kept in an inert
position through pH.
Hence sodium chlorite has a pH of 13.
Lowering the pH of sodium chlorite release chlorine dioxide.
pH 7 trace amounts
pH 5 5%
pH 3.5 10%
pH 2.5 60%
pH 1 100%
Traditionally, chlorine dioxide for disinfection applications has been made by one of three methods using sodium chlorite or the sodium chlorite - hypochlorite or the sodium chlorite - hydrochloric acid method:
Chlorine dioxide is used in many industrial water treatment applications as a biocide including cooling towers, process water and food processing. Chlorine dioxide is less corrosive than chlorine and superior for the control of legionella bacteria.
All three sodium chlorite chemistries can produce chlorine dioxide with high chlorite conversion yield, but unlike the other processes the chlorite-HCl method produces completely chlorine free chlorine dioxide but suffers from the requirement of 25% more chlorite to produce an equivalent amount of chlorine dioxide.
The main application of sodium chlorite is the generation of chlorine dioxide for bleaching and stripping of textiles, pulp, and paper. It is also used for disinfection of a few municipal water treatment plants after conversion to chlorine dioxide.
ACIDIFIED SODIUM CHLORITE
Acidified Sodium Chlorite (ASC) is approved by the FDA (21 CFR 173.325) as a ‘secondary direct food additive permitted in food for human consumption’ specifically as an antimicrobial intervention treatment for poultry carcasses, poultry carcass parts, red meat carcasses, red meat parts and organs, seafood, and raw agricultural commodities.
ASC is often confused with chlorine dioxide (ClO2), also approved by the FDA (21 CFR 173.300) as a secondary direct food additive largely because solutions ASC can, under certain conditions, generate small quantities of chlorine dioxide. However, by judicious selection of reaction parameters (nature and concentration of activating acid, chlorite concentration, catalysts, total titratable acidity) chlorine dioxide formation is typically minimized in true ASC solutions. ASC is a highly effective, broad spectrum antimicrobial, which is produced by lowering the pH of a solution of sodium chlorite into the 2.5 to 3.2 range with any GRAS acid.
ASC chemistry is principally that of chlorous acid (HClO2), which is the metastable oxychlorine species, which forms on acidification of chlorite. Once formed, chlorous acid gradually decomposes to form chlorate ion, chlorine dioxide, and chloride ion. It is hypothesized that the mode of action of ASC derives from the uncharged chlorous acid, which is able to penetrate bacterial cell walls and disrupt protein synthesis by virtue of its reaction with sulfhydryl, sulfide, and disulfide containing amino acids and nucleotides. The undissociated acid is thought to facilitate proton leakage into cells and thereby increase energy output of the cells to maintain their normal internal pH thereby also adversely affecting amino acid transport. Iodometric titration and UV spectroscopic methods must be used to allow an accurate determination of the active concentrations present in an ASC solution and to differentiate them from typical chlorine dioxide generating systems.
A number of products are marketed as "stabilized chlorine dioxide" (SCD). Most of these solutions do not actually contain chlorine dioxide but consist of solutions of buffered sodium chlorite. A weak acid can be added to SCD to "activate" it and make chlorine dioxide in-situ without a chlorine dioxide generator.
Hope this helps shorty I put 2 hours work into it!