****!!!!****!!!!*** "In alkaline media the permeability of living cell walls to gaseous chlorine dioxide radicals seems to be increased allowing an easier access to vital molecules. The reaction of chlorine dioxide with vital amino acids is one of the dominant processes of its action on bacteria and viruses. Compounds within the cells and on the surface of cell membranes that contain oxidisable material react with chlorine dioxide, causing cell metabolism to be disrupted. Chlorine dioxide also reacts directly with disulphide bonds in the amino acids and the RNA in the cell. Unlike non-oxidizing disinfectants, chlorine dioxide kills microorganisms even when they are inactive. The oxidative load placed on the cells by the action of chlorine dioxide mean that most microorganisms are unable to build up resistance to chlorine dioxide." In practical terms however, few bacteria live alone, and they are most often found in water and on surfaces in the form of a "biofilm" which is a close association of many millions of bacteria. Many biocides have particular problems in penetrating this biofilm, due to the polysaccharide "glue" that is secreted by bacteria such as Pseudomonas to hold the biofilm together. Unlike most biocides, chlorine dioxide can effectively penetrate the polysaccharide layer of biofilm without being used up in reacting with the inert sugars. This allows the ClO2 to act on the bacteria themselves, destroying the biofilm."

****!!!!**** "Chlorine dioxide chemistry works by selective oxidation, targeting the biocide where it is needed most." "Generally Chlorine Dioxide (ClO2) rapidly oxidises phenol type compounds, secondary and tertiary amines, organic sulphides and certain hydrocarbon polycyclic aromatics such as benzopyrene, anthracene and benzoathracene. In general, Chlorine Dioxide will not react on double carbon bonds, aromatic cores, quinionic and carboxylic structures as well as primary amines and urea. Commercial applications have shown that Chlorine Dioxide can effectively oxidise many compounds considered to be waste and water pollutants. The table below lists a selection of pollutants found in various industries from our files, and demonstrates the wide range of possible applications for Chlorine Dioxide... Aldehydes... Amines and Mercaptans" "Chlorine Dioxide, however reacts with THM precursors primarily by oxidation to make them non-reactive or unavailable for THM production."

"Our KyroCAPS represent an innovative and patented capsule system that does not affect the smell, taste or pH value of the water."

***!!!!***!!*** {Includes useful explanation of ppm} "Unit of ppm: ppm (parts per million) represents the ratio of 1 part per million. The weight ratio (mg / L = ppm, 1 L water is approximately equal to 1 kg) is used for liquids, and the volume ratio is used for gas. The ppm of this test applies the weight ratio in aqueous solution."

****!!!!****!!!!**** "optimum conditions for the production of gaseous chlorine dioxide (ClO2) from aqueous ClO2 (HCl+NaClO2). When 1 N HCl was reacted with various concentrations of NaClO2 (50,000-500,000 mg/mL), the highest concentration (695 mg/L) of gaseous ClO2 was obtained from the aqueous ClO2 containing 100,000 µg/mL NaClO2. Next, the effects of relative humidity (RH; 43, 85, and 100%) and temperature (4, 12, and 25ºC) on the production of gaseous ClO2 were investigated. It was observed that the concentration of gaseous ClO2 was increased as RH was decreased, or the temperature was increased. Finally, it was confirmed that the amount of gaseous ClO2 was highly correlated (R2=0.9546-0.9992) with the volume of aqueous ClO2."

****!!!!**** "the reaction between the ferrous ion and chlorite is very fast (5–15 s) over a range of pH 6.5–8.0; in this condition a ferrous ion dose of 3.31 mg Fe/mg ClO2 completely reduced chlorite to chloride, producing minimal residual soluble iron. For pH higher than 8.0–8.5, chlorite removal is lower due to the natural transformation of the ferrou ions to ferric hydroxide. Within these pH values, chlorite can be removed completely with ferrous ion concentrations higher than the stoichiometric value. Moreover, the application of ferrous salts for chlorite removal during the coagulation process enhances the performance of the coagulation and flocculation treatment"

"This study assessed the antimicrobial properties of Aseptrol® (48 ppm and 24 ppm)" "Both disinfectants killed more susceptible bacteria, such as Staphylococcus aureus, Pseudomonas. aeruginosa and Streptococcus mutans within 30 seconds and proved to be fungicidal by killing Candida albicans within 30 seconds.Aseptrol® and Presept® killed less susceptible mycobacteria such as Mycobacterium tuberculosis, Mycobacterium avium subsp. avium and blood borne organism Hepatitis B virus within 30 seconds. Highly resistant B. subtilis spores were killed in 2 and 2.5 minutes by Aseptrol® and Presept® respectively." "Although manufacturers recommend that the disinfectant solutions should be prepared daily, when the shelf-life of prepared solutions stored in screw cap bottles was studied, the results showed that Aseptrol® can be effectively used for 27 day" "nosocomial infections"

***** "ClO2 at 10 μg ml−1 effectively reduced conidial germination of all decay fungi tested after treatment for 0·5 min. Chlorine dioxide only kills by contact, not systemically, and is effective only on exposed fungal propagules, such as those suspended in water or on the surface of fruit. It does not kill pathogens under the fruit skin or active infections. Chlorine dioxide can be difficult to use indoors because when a treated water stream is agitated or aerated, some of the ClO2 comes out of solution and enters the atmosphere. There is a permissible exposure level of 0·1 μg ml−1 in the air, but workers will respond to the odour before that level is reached. In USA, for this reason the recommended rate for indoor applications is μg ml−1 or less"

"The inactivation mechanisms were explored by analyzing the leakage of intracellular substances, the increase in extracellular adenosine triphosphate (ATP), deoxyribonucleic acid (DNA), and proteins as well as the changes in spore morphology. The kinetics of inactivation by chlorine dioxide fitted the Chick-Watson model, and different fungal species showed different resistance to chlorine dioxide inactivation, which was in the following order: Cladosporium sp.>Trichoderma sp. >Penicillium sp., which are much more resistant than Escherichia coli." "Regarding the three genera of fungal spores used in this study, chlorine dioxide was more effective at inactivation of fungal spores than chlorine." "The effect of disinfectant concentration and temperature was positive, and the impact of pH levels (6.0 and 7.0) was insignificant, whereas the influence of water matrices on the inactivation efficiency was negative. The increased concentration of characteristic extracellular substances and changes of spore morphology were observed after inactivation with chlorine dioxide and were due to cell wall and cell membrane damage in fungal spores, causing the leakage of intracellular substances and death of a fungal spore."

****!!!!*** "ule type that potentially had low sensitivity to ClO2. The information generated from this research indicates whether a narrow or wide range in rate of ClO2 is needed for efficacy against different fungal propagules as a result of the interactions of water properties (e.g., pH and water hardness) that vary with the source (e.g., ponds, wells, municipal water, and recirculating systems), in combination with the presence of nutrient leachates that collect in catchment ponds and ebb-and-flow systems" " a high reduction in viable propagules resulted when conidia or sporangiospores of Botrytis cinerea, Penicillium expansum, Mucor piriformis, and Cryptosporiopsis perennans... These papers demonstrated that concentration of ClO2 varies with time, with an equal mortality of propagules obtained at lower concentrations of ClO2 by lengthening the duration of exposure. " "A higher concentration of ClO2 was required at pH 8 than at pH 5 to achieve a lethal dose resulting in 50% mortality of spores (LD50). The addition of the divalent metal ion solution required an increase in ClO2 concentration to maintain a LD50. When combined with the nitrogen and hard water solution, the divalent metal ion solution placed a higher demand on ClO2 at pH 5 and a lower demand on ClO2 at pH 8,"

{Good FAQ info} "It delivers broad spectrum performance against bacteria, fungi, algae, viruses, and parasitic microorganisms. ClO2 kills vegetative microorganisms and effectively deactivates sporulated species."

{Includes chart of critical levels for pathogens in water} "Shock treatment is recommended twice a year and usually requires a concentration of 20-50ppm chlorine dioxide be maintained for 12 hours, and then the irrigation system thoroughly rinsed before irrigation begins again, due to risk of phytotoxic effects with high concentrations. After shock treatment, a continuous treatment of 0.25ppm residual chlorine dioxide is usually sufficient to prevent regrowth of biofilm. " "The optimum chlorine dioxide range to treat biofilms and common plant pathogens is 0.25 to 3.3 ppm"

*****!!!!*** {Very useful info on chemistry. List of susceptible pathogens} "Chlorine dioxide exists in the water as ClO2 (little or no dissociation) and thus is able to permeate through bacterial cell membranes and destroy bacterial cells (Junli et. Al, 1977b). its action on viruses involves adsorbing onto and penetrating the protein coat of the viral capsid and reacting with the viral RNA... As a result, the genetic capability of the virus is damaged (Junli et. Al, 1977a). In comparison to chlorine, chlorine dioxide can be more effective as a disinfectant due to the fact that chlorine exists in the water as HOCL or OCL-. As a result, bacterial cell walls are negatively charged and repel these compounds, leading to less penetration and absorption of the disinfectant into the membranes. " "ClO2 DOES NOT REACT WITH: hippuric acid, cinnamic acid, betaine, creatine, alanine, phenylalanine, valine, leucine, asparaginic acid, asparagine, glutaminic acid...."

"virucidal effects of disinfectants by adding 15 μL of SARS-CoV-2 culture... to 135 μL of various disinfectants at working concentration ... With the exception of a 5-min incubation with hand soap, no infectious virus could be detected after a 5-min incubation at room temperature (22°C). Additionally, we also found that SARS-CoV-2 is extremely stable in a wide range of pH values at room temperature ... Overall, SARS-CoV-2 can be highly stable in a favourable environment,4 but it is also susceptible to standard disinfection method"

"using modified maifanshi as the carrier and sodium chlorite and solid acid as the main agent, a new solid chlorine dioxide disinfectant that can release chlorine dioxide can be prepared by relying on environmental humidity, and the effect of the addition amount, activation temperature, various additives and environmental humidity on the release rate of chlorine dioxide was investigated. the results show that the addition of maifanshi can significantly reduce the peak of the release rate, eliminate the phenomenon of violent release, make the release rate in the later stage larger, and enhance the sterilization effect in the later stage; activation of maifanshi can enhance its adsorption capacity, and the optimal activation temperature is 100 °c; the addition of a certain amount of magnesium sulfate, calcium chloride and superabsorbent resin can make the release rate better controlled; the smaller the relative humidity, the more gentle the release of chlorine dioxide."

*** {Excellent Powerpoint presentation about chlorine dioxide, building decontamination, etc}

****!!!!***!!!!***!!!!** "Spike protein was first mixed with various concentrations of CD... at room temperature for 5 min." "CD at 0.25 mmol/L or 0.5 mmol/L was effective in inactivating the binding of the spike protein to ACE2.. However, CD was not effective at 0.1 mmol/L concentration. The result strongly suggests that CD in sufficient cnocentration is effective in inactivating the spike protein of SARS-CoV-2 coronavirus and thus preventing its binding to human cells."

****!!!!**** "The inactivation of virus and the inhibition of specific attachment both increased with increasing pH and increasing disinfectant concentration." "Inactivation of f2 was hypothesized to occur as the result of chlorine dioxide reacting with discrete chemical moieties in the viral protein. Cysteine, tyrosine and tryptophan reacted with chlorine dioxide within a time frame that could affect viral inactivation. In denatured f2 capsid protein monomers, these amino acids were almost totally degraded within 2 min by chlorine dioxide. Only tyrosine reacted with chlorine dioxide following treatment of the intact virion with disinfectant. Even though the degradation of tyrosine residues occurred at a much slower rate than the rate of virus inactivation, the protein component of f2 virus appeared to be the site of the lethal lesion produced by chlorine dioxide. These tyrosine reactions with chlorine dioxide appeared to alter the virus such that specific attachment was inhibited."

****!!!!****"If you buy a 2% CLO2 product (Oxine), you are actually getting a 3.35% Sodium Chlorite in that jug or drum. It is essentially a 1.67 multiplier from the percentage of CLO2 that product claims." "Sodium Chlorite is widely used as a sanitizer and can be effective at inhibiting bacteria. It is important to know that chlorite solutions can carry anti-microbial claims listed as static or stasis by the EPA. That means chlorite solutions can inhibit or prevent bacteria growth of present organisms" [without necessarily destroying them] "we have found the liquid inorganic acids like LpH 100 work best and allow for less acid to be used with higher conversion to CLO2." "Contact time with your acid or ‘activator’ and pH of the working solution your acid is creating. Those two dynamics will determine how much Chlorine Dioxide you actually generate." "When using 5% stabilized CLO2 products like Pro Oxine after you achieve proper activation you will convert about 25% to 30% of that solution to CLO2. 70 to 75% of that solution will remain chlorite and be a part of your TOTAL working solution. The remaining sodium chlorite is important and will play a critical role in how well your product works over time." "Bio-Cide’s AANE [Automatic Activation Non Electric] system... to deliver product without ever having to mix products but allows for proper contact time and pH in your working solution to generate FREE CLO2 in your water system. The system is very easy to set up and can be used with any pump system you already have" "So you can essentially have 1.8 ppm TOTAL and .8 ppm FREE under the potable water claim approved by the EPA." " you never have to turn off your system to run other supportive care products or water soluble antibiotics. Since CLO2 is a ‘selective’ oxidizer it doesn’t seem to negatively affect these other products"

****!!!!**** List of chlorine dioxide generation companies, manufacturers and suppliers worldwide

****** "The most common method of generating ClO2 is through the reaction of chlorine gas with a solution of sodium chlorite. Theoretically, 1 lb of chlorine gas is required for each 2.6 lb of sodium chlorite. However, an excess of chlorine is often used to lower the pH to the required minimum of 3.5 and to drive the reaction to completion. Sodium hypochlorite can be used in place of the gaseous chlorine to generate chlorine dioxide. This process requires the addition of sulfuric or hydrochloric acid for pH control. Other methods used for chlorine dioxide generation include:..." "Complex organic molecules and ammonia are traditional chlorine-demand materials that do not react with chlorine dioxide. " "The chemical behavior and oxidation characteristics of aqueous chlorine dioxide are not well understood because of the difficulty in differentiating aqueous chlorine-containing species." "Chlorine dioxide consumed in water treatment reactions reverts to chlorite ions (ClO2-), chlorate ions (ClO3- ), and chloride ions (Cl -)." "As a gas, chlorine dioxide is more irritating and toxic than chlorine. Chlorine dioxide in air is detectable by odor at 14-17 ppm, irritating at 45 ppm, fatal in 44 min at 150 ppm, and rapidly fatal at 350 ppm. Concentrations greater than 14% in air can sustain a decomposition wave set off by an electric spark. The most common precursor for on-site generation of chlorine dioxide is also a hazardous material: liquid sodium chlorite. If allowed to dry, this powerful oxidizing agent forms a powdered residue that can ignite or explode if contacted by oxidizable materials. The hazardous nature of chlorine dioxide vapor and its precursor, and the volatility of aqueous solutions of chlorine dioxide, require caution in the design and operation of solution and feeding equipment."

"An interesting feature of the reactions in acid solution is that chlorine dioxide is frequently a product. Although not a stable end-product, it persists for long periods of time; both the rate at which it disproportionates and the rate at which it reacts with chlorine in other oxidation states in acid at room temperatures are slow. Chlorine dioxide appears in the disproportionation of chlorate in acid, in the reduction of chlorate by chloride ion, the oxidation of chlorite by chlorine or hypochlorous acid and the disproportionation of chlorite in acid."

****!!!!****!!!!*** (2020) "ClO2 gas is easy decomposed under sun light so there is little tendency to form organochlorine by-products (Karsa, 2007)."

****!!!!*** {Cited by 175 documents}

****!!!!*** "Only a few amino acids have been reported to be reactive with ClO2, and they have been found to follow second-order kinetics for the overall reaction. The rate constants vary from 10−2 to 107 M−1 s−1 and follow an order of reactivity: cysteine > tyrosine > tryptophan > histidine > proline. For reactions of histidine, tryptophan, and tyrosine with ClO2, products vary depending largely on the molar ratios of ClO2 with the specific amino acid. Products of ClO2 oxidation differ with the presence or absence of oxygen in the reaction mixture. Excess molar amounts of ClO2 relative to amino acids are associated with the production of low molecular weight compounds. The oxidation of the biochemically important compounds bovine serum albumin and glucose-6-phosphate dehydrogenase by ClO2 suggests a denaturing of proteins by ClO2 by an attack on tryptophan and tyrosine residues and relates to the inactivation of microbes by ClO2."

****!!!!****** {Includes equations for predicting impact of variables in determining quantity of byproducts} "At 20oC, pH 7, 70-80% of chlorine dioxideinjected was converted to chlorite and 0-10% of that was transformed into chlorate within 120 min with 2.91 mg/Lof DOC. The amount of chlorite formed also increased when pH and temperature increased. As DOC content increased,the residual chlorine dioxide decreased but the amount of chlorite and chlorate were increased. These experimentsrevealed that chlorate was a dominant by-product under UV irradiation."

**** {Mix with dry citric acid, or 33% phosphoric acid} "Alternatives to citric acid for activation include organic acids, such as acetic acid, and inorganic acids such as phosphoric, hydrochloric, and sulfuric acids. Activation equivalent to that of citric acid may be achieved by adjusting the Pro Oxide solution to pH 2-3 with an alternative acid." "allow to dissolve for five minutes for citric acid or two minutes for phosphoric acid"

2005