Chemical & Biological Dynamics

{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...

{Note: Click blue download button for full text} "The results showed that 200–1800 mg/L of ClO2 significantly inhibited the incidence of green mold on kumquats, mandarins, Peru’s oranges, and grapefruits caused by P. digitatum. Additionally, 200 mg/L of ClO2 significantly induced cell apoptosis of P. digitatum by increasing the fluorescence intensity of the mitochondrial membrane potential from 118 to 1225 and decreased the living cell rate from 96.8 to 6.1%. Further study demonstrated that the content of malondialdehyde and nucleic acid leakage (OD260) of P. digitatum markedly increased, and the mycelial morphology was seriously damaged with increased ClO2 concentration"

"sanitizing regimes on... stainless steel, wood, and rubber conveyor material." "Of the range of chlorine dioxide concentrations and contact time regimes evaluated for all surfaces, the most effective concentration/time regime applied was 100 ppm for 10 min. Reductions ranged from 0 to 4.5 log CFU/coupon. ***Chlorine dioxide was least effective when applied to wood.***"

"Similarly, the sensitivity of the C. difficile spores to disinfectants No. 2 [chlorine dioxide] and 3 was somewhat higher."

"We found that over 30 min, chlorine dioxide did not change the Raman spectrum or the spore structure" "We conclude that vibrational spectroscopy provides powerful means to detect changes in spores but it might be problematic to identify if spores are live or dead after a decontamination procedure."

****!!!!****!!!!****!!!! "Novel Technology to Reduce Risk of Viral Transmission in Enclosed Occupied Environments and Room Disinfection in Unoccupied Spaces, METSS Corporation: ... development of a novel chlorine dioxide (ClO2) gas dispersion system under a current EPA-sponsored Phase II SBIR project...). The system design offers a safe and effective means to rapidly generate ClO2 vapor for on-site room decontamination in hospital and non-hospital settings. This technology is intended to meet the demands of health care markets committed to decontaminate porous materials and sensitive equipment in rooms or vehicles used for care or transport of Ebola-exposed patients... current COVID-19 pandemic has demonstrated a clear need for technologies aimed at occupied spaces to reduce or prevent the spread of transmissible diseases through air or contact with surfaces contaminated with infectious microdroplets." "y. During repeated trials, METSS demonstrated the efficacy of low level ClO2 against Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae. Additional efficacy testing was performed using MS2 (non-enveloped) and Phi6 bacteriophage (enveloped) as surrogates to SARS-CoV-2 and other human viruses...." "Decontamination of Covid-19 Vaccine Production Facility: ...a study completed within the United States Pharmaceutical Industry alongside ClorDiSys Solutions, Inc established evidence that chlorine dioxide gas has the capacity to inactivate beta-lactams" "t to achieve a 3-log reduction of beta-lactams, an inactivation cycle consisting of a 30-minute conditioning phase at 75% relative humidity, followed by an exposure to chlorine dioxide gas of at least 7,240 ppm-hours, is required. Chlorine dioxide destroys the beta-lactam ring and inactivates the compound, in similar fashion to the manner in which penicillin-resistant organisms act" "exposing the target beta-lactam to Chlorine dioxide gas at a concentration of 5mg/L" "Outdoor Systems Trial Using Full-Scale Agricultural Equipment for Wide Area Decontamination of Bacillus anthracis Surrogate Spores": ...we exploited state-of-the-art spray application technologies and formulation chemistry used in the agricultural industry, spore germination techniques and a novel decontaminant based on the targeted release of chlorine dioxide. Spores of B. thuringiensis HD-1 cry- were employed as a surrogate for virulent B. anthracis. However, key performance attributes were validated against a range of virulent B. anthracis. Preferred formulations for decontamination were developed through laboratory, environmental chamber, windtunnel and finally full-scale outdoor trials. During outdoor trials we achieved all essential success criteria on all surface types (4-Log10 reduction on wood, steel and cement). Results using steel surfaces approached that required for desirable performance (6-Log10 reduction). Significant loss of spore viability was found by environmental exposure alone (up to 3-Log10 over 72 h). However, active decontamination was more effective (up to a further 3.6-Log10 reduction in viable spores). Pre-germination before decontamination with chlorine dioxide was not found to have a benefit." "Use of Innovative Packaging to Facilitate On-Site Treatment of Waste from a Bacillus anthracis Release Incident: ...These semi-permeable materials would allow gaseous fumigants such as chlorine dioxide (ClO2) to pass into the bags but would not allow residual spores to penetrate the walls of the bags and exit into the atmosphere. Testing is currently occurring... to assess the ability of the materials to allow ClO2 to penetrate through the bag material and... to provide sufficient concentration-time exposure of the waste inside the permeation chamber"