Chemical & Biological Dynamics

****!!!!**** (1943) {Note: Air sanitizers using glycol can be easily registered with EPA using basic data. Other substances require more data submission.} "The killing process was found to be more effective when both the total number of air-borne droplets and the number of organisms in the bacterial suspension are small. A temperature below 80°F. and an atmospheric relative humidity between 45 and 70 per cent were found to constitute the most favorable conditions for the lethal action of the vapor. Experiments were performed to test the bactericidal efficiency of propylene glycol vapor in both small and large enclosed spaces. These studies revealed that equally marked bactericidal action is obtained when propylene glycol is dispersed in an 800 cubic foot room as occurs in chambers of 2 cubic foot capacity. The susceptibility to vapor action of bacteria re-suspended in saliva was just as great as when broth was used as the suspending medium. Both partially and completely dehydrated bacteria also succumbed to the effects of the vapor. However, when unsterile dust collected from inhabited rooms was dispersed into the air, little reduction of the natural microbic population contained in this material was observed."

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{Spectrum Doxyicide LLC} "devices, systems, and methods for producing broad spectrum disinfectants using a colloidal suspension of chlorine dioxide in deionized water, and more particularly, producing chlorine dioxide compositions that clean, disinfect and/or sterilize in one step with no harmful byproducts"

(1949)

{Not FDA approved} "Active ingredient: Chlorine Dioxide. Ther ingredients: Sulfuric acid magnesium salt, Sodium Cholorite, Carbonic acid monosodium salt, Sulfuric acid monosodium salt monohydrate, Sulfuric acid disodium salt."

{Supplement to main article}

"Phenols... Below pH 10, a minimum of 1.5 mg/L of chlorine dioxide oxidizes 1 mg/L of phenol to benzoquinone." "Algae... adding chlorine dioxide to the reservoir at night (to prevent decomposition of chlorine dioxide by sunlight). The algae killing action is fast enough to be effective before the sun rises. A dosage of 1 mg/L " "Sulfides - it does rapidly oxidize hydrogen sulfide to sulfates in the pH range 5-9. Between pH 5-9, a minimum of 3.36 mg/L of chlorine dioxide should be used to instantly oxidize 1 mg/L of sulfide to sulfate."

The sulfide–chlorine dioxide reaction was found to have two distinct kinetic stages at alkaline conditions. The first stage proceeds so rapidly that it can only be measured by a stopped-flow technique at low temperature and leads to the parallel formation of polysulfide and sulfate as sulfur-containing products. At the same time, chlorite, chlorate, and chloride are produced from chlorine dioxide in detectable amounts, suggesting a complex stoichiometry. A nine-step kinetic model including short-lived intermediates like sulfide radical and •HSClO2– is proposed to describe the kinetic data in this rapid stage. In an excess of chlorine dioxide, the first stage is followed by a significantly slower one to be measured by conventional UV–vis spectroscopy at room temperature. Considering that tetrasulfide is formed during the first rapid course of the reaction, the subsequent slow kinetic stage can only be described by the direct oxidation of tetrasulfide by chlorine dioxide and, surprisingly, the tetrasulfide-catalyzed disproportionation of chlorine dioxide.

A classical electron-transfer mechanism is assigned to the reaction that occurs under conditions of methionine inhibition, and the initial products are ClO2(-) and S4O6(2-). The reaction of ClO2(•) with S2O3(2-) in aqueous solution is a component of the "crazy clock" reaction of ClO2(-) with S2O3(2-), and under conditions of excess S2O3(2-) the absorbance at 360 nm due to ClO2(•) decays with sigmoidal kinetics. A chain reaction mechanism is inferred on the basis that very small concentrations of SO3(2-) accelerate the reaction, and methionine inhibits the reaction. Pseudo-first-order kinetics is observed in the presence of relatively large methionine concentrations, leading to the simple rate law -d[ClO2]/dt = (ka[S2O3(2-)] + kb[S2O3(2-)](2))[ClO2], with ka = 452 ± 16 M(-1) s(-1) and kb = (5.7 ± 0.2) × 10(5) M(-2) s(-1) at 25 °C and pH 7.6. Under these conditions, the initial products are ClO2(-) and S4O6(2-). A classical electron-transfer mechanism is assigned to the reaction that occurs under conditions of methionine inhibition.

The kinetics of the oxidation of a substituted thiourea, trimethylthiourea (TMTU), by chlorite have been studied in slightly acidic media. The reaction is much faster than the comparable oxidation of the unsubstituted thiourea by chlorite. The stoichiometry of the reaction was experimentally deduced …

"used for two purposes in this application. First, as a chemical oxidant to oxidize the sulfides to sulfates, thus preventing the formation of colloidal sulfur or iron sulfide which can plug the well, and, second, as a biocide to kill the bacteria which produce the sulfides." "For intermittent treatment, chlorine dioxide should be applied at a shock dosage of 200 - 3000 ppm"

**** [Highlights non-ClO2 water treatment with great potential] "Advanced oxidation is a process that applies enough hydroxyl radicals to achieve significant change at the molecular level. The hydroxyl radical is a reactive oxygen species with the highest oxidation potential among all oxidizing agents used in water treatment. It is mainly non-selective and reacts by decomposition with most compounds it encounters on its path. In 2013, the International Sanitary Foundation certified NSF/ANSI 60, the first advanced oxidation reagent for the treatment of drinking water for human use. This reagent is a multimineral oxychloride liquid formula that does not need to be generated onsite, has low safety risk, and is cheaper and simpler to operate than other chlorine alternatives."

(1982)

"the chlorine dioxide generator requires some simple electrolyte preparation. Both generators eventually need calibration themselves by the manufacturer.... Chlorine Dioxide (ClO2)... can also be calibrated using chlorine (Cl2) as a surrogate gas, which is available in a cylinder. For ClO2, 1.0 ppm Cl2 is appropriate, with the span value set at the 0.6 ppm equivalent concentration"

[Safety measures for using chlorine dioxide in industrial environment]

****!!!! {Highlights of chlorine dioxide characteristics} "ClO2 does not ionize to form weak acids (as chlorine and bromine do) in aqueous solutions. This allows ClO2 to be effective over a wide pH range. " "The criteria for disinfection, as defined by the USEPA, are as follows. ClO2 meets all of these criteria. 1. a 99.9% reduction in Giardia lamblia (3 log reduction) 2. zero lactose fermenting coliform 3. less than 10 cfu/mL non-lactose fermenting coliforms and 4. 99.99% reduction in enteric virus (4 log) concentrations." "ClO2 is shown to be an effective disinfectant at residual concentrations between 0.2 and 0.8 ppm. ClO2 penetrates the cell wall of the microorganism and disrupts metabolic functions. This is more efficient than other oxidizers that “burn” whatever they come in contact with. This allows lower effective concentrations to be used. ClO2, like ozone, is a dissolved gas that penetrates biofilm by molecular diffusion. However, unlike ozone, ClO2 is stable and soluble, allowing it to travel to the base of the film where it attacks microorganisms and attacks and loosens the biofilm at its point of attachment. Other oxidizers react mostly on the surface of the biofilm to form an oxidized layer, like charring on wood. This precludes further penetration. No biocide has proved to control biofilm better than ClO2. "

"ClO2. This is a reactive gas formed from chlorine and oxygen. It is a strong oxidizing agent with a tendency to open up unsaturated compounds and aromatic rings. In water solution it may be present as an ion with a single negative charge. Function: Papermakers who use bleached kraft pulp are likely to have heard about chlorine dioxide even if they have never set foot in a pulp mill. That's partly because it is very often present in the very last bleaching stage (D-stage), increasing the likelihood that some of it is carries over with the pulp into the paper machine system. Another reason is that it is one of the most popular biocide treatments for alkaline papermaking. Its use in that role is pretty much restricted to bleached grades, since any unbleached fibers will rapidly consume the chemical. Strategies for Use: Chlorine dioxide has the desirable attribute of "quick kill" of bacteria and fungi, and it also decomposes relatively rapidly. It is conventional practice to treat the pulp furnish and then monitor the residual activity at a later point in the process. Typically the addition rate is controlled to give a residual chlorine content of about 1 ppm."

Bleaching is a whitening process that is used in the paper industry to produce paper with high brightness. Chemicals—such as chlorine gas (C), sodium hypochlorite (H), oxygen (O), hydrogen peroxide (X), ozone (Z), and chlorine dioxide (D)— are used in various combinations to produce pulp with the desired properties

Eka chlorine dioxide is a preferable bleaching agent used in the production of elemental chlorine-free (ECF) bleached chemical wood pulp all over the world.

****!!!!****!!!!*** "Materials to Avoid (Incompatible Materials): LNG vapors will form explosive mixtures with air or oxygen and will also burn or explode in the presence of strong oxidizing agents such as chlorine, chlorine dioxide, bromine pentafluoride, oxygen difluoride, liquid oxygen, and nitrogen triflouride. LNG will spontaneously ignite when mixed with chlorine dioxide. "

****!!!!****!!!!***** "An aqueous solution of ClO2 at 126 ppm (w/w) for 15 s was effective, and no surviving virus was detected with the hemagglutination test. ClO2 gas at 5 ppm (v/v) sustained for 1 h inactivated the virus effectively, while at 2.5 ppm for 1 h only partially inactivated the virus."

(2001)

"Biological tests demonstrated that the inactivation of Nosema bombycis (N. bombycis) spores by chlorine dioxide (ClO2) occurs very fast and is highly sensitive. The lowest effective inactivation dosage and time was 15 mg/mL for 30 min. "

Thalassas: An International Journal of Marine Sciences - Chlorination is a widespread fouling control practice in water intake structures of power plants and desalination plants. Chlorine dioxide...