Chemical & Biological Dynamics

2013 ***!!!!*** "Tailing occurs even at constant ClO2 concentrations. The chlorine dioxide solution’s disinfecting capacity, virus aggregation and the resistant subpopulation were ruled out as reasons for tailing. Instead,the cause for tailing is the deposition of an adduct onto the virus capsid over the course of the experiment, which protects the viruses. This adduct could easily be removed by washing, which restored the susceptibility of the viruses to ClO2." "Important shortcoming of ClO2, namely its self-limiting effect on virus disinfection. Important to take this effect into account in treatment application." "Working solution of 0.410.7 mg/L chlorine dioxide. To compensate for ClO2evaporation and consumption throughout the experiment,concentrated ClO2(16 mg/L) was added at a rate of 8e20mL/min by means of a peristaltic pump."

The reactions between aqueous ClO2 and guanosine 5'-monophosphate (5'-GMP) are investigated from pH 5.96 to 8.30. The decay of ClO2 follows mixed first-order and second-order kinetics. The addition of chlorite (0.01-0.05 M) to the reaction mixture suppresses the reaction rate and changes the observe …

"Surprisingly, a mechanistic understanding of ClO2 reactions in (waste)water matrices is largely lacking"

Chlorination of drinking waters leads to the formation of trihalomethanes arising from the reaction of chlorine and organic substances. Therefore, chlorine dioxide (ClO2) which does not produce trihalomethanes is being considered as an alternative disinfectant. It has been reported that rat blood ch …

In this study, chlorine dioxide (ClO2) was used as an alternative disinfectant with vanillic acid, p-hydroxybenzoic acid, and humic acid as the organic precursors in a natural aquatic environment. The primary disinfection by-products (DBPs) formed were trihalomethanes (THMs) and haloacetic acids (HA …

1982

""O₂-generating reactions are exceedingly rare in biology and difficult to mimic synthetically. Perchlorate-respiring bacteria enzymatically detoxify chlorite (ClO₂(-) ), the end product of the perchlorate (ClO(4)(-) ) respiratory pathway, by rapidly converting it to dioxygen (O₂) and chloride (Cl(-)). This reaction is catalyzed by a heme-containing protein, called chlorite dismutase (Cld), which bears no structural or sequence relationships with known peroxidases or other heme proteins and is part of a large family of proteins with more than one biochemical function. The original assumptions from the 1990s that perchlorate is not a natural product and that perchlorate respiration might be confined to a taxonomically narrow group of species have been called into question, as have the roles of perchlorate respiration and Cld-mediated reactions in the global biogeochemical cycle of chlorine. ""

"O₂-generating reactions are exceedingly rare in biology and difficult to mimic synthetically. Perchlorate-respiring bacteria enzymatically detoxify chlorite (ClO₂(-) ), the end product of the perchlorate (ClO(4)(-) ) respiratory pathway, by rapidly converting it to dioxygen (O₂) and chloride (Cl(-)). This reaction is catalyzed by a heme-containing protein, called chlorite dismutase (Cld), which bears no structural or sequence relationships with known peroxidases or other heme proteins and is part of a large family of proteins with more than one biochemical function. The original assumptions from the 1990s that perchlorate is not a natural product and that perchlorate respiration might be confined to a taxonomically narrow group of species have been called into question, as have the roles of perchlorate respiration and Cld-mediated reactions in the global biogeochemical cycle of chlorine. "

"Chlorite dismutases (Clds) are therefore important molecules in bioremediation as Clds catalyze the degradation of chlorite to chloride and molecular oxygen."

Reactions of aquacobalamin (H2O-Cbl(III)) and its one-electron reduced form (cob(II)alamin, Cbl(II)) with chlorite (ClO2-) and chlorine dioxide (ClO 2• ) were studied by conventional and stopped-flow UV-Vis spectroscopies and matrix-assisted las …

We evaluated the lethal activity of gaseous chlorine dioxide (ClO2) against Bacillus cereus spores attached to and in biofilm formed on a stainless st…

To control the waterborne transmission of enterovirus 71(EV71), which is associated with hand foot and mouth disease (HFMD), it is essential to know the inactivation effectiveness of disinfectants on EV71 in water. In this article, we present a comparative analysis of the effects on EV71 following exposure to chlorine dioxide (ClO2) under different doses, pH, and temperature conditions. We show that the EV71 exhibited strong resistance to ClO2 (more than the MS2 standard) and that Ct value ranges required for a 4-log reduction of EV71 in buffered, disinfectant demand-free water at pH 7.2 an...

****Chlorine dioxide was not very effective at decontaminating bare pine wood. Testing included DioxiGuard 400 ppm (manufacturer Frontier Pharm had indicated would be 190 ppm) chlorine dioxide, and SanDes 1500 ppm chlorine dioxide. Tested surfaces: industrial‐grade carpet, decorative laminate, galvanized metal ductwork, painted wallboard paper, painted cinder block, bare pine wood and glass.

{**Reactions with metal in pipes} "The possible ClO2 loss and the formation of chlorite/chlorate should be carefully considered in drinking water distribution systems containing copper pipes."" Metal oxides generally enhanced ClO2 decay in a second-order process via three pathways: (1) catalytic disproportionation with equimolar formation of chlorite and chlorate, (2) reaction to chlorite and oxygen, and (3) oxidation of a metal in a reduced form (e.g., cuprous oxide) to a higher oxidation state."

"In experiments A) and B) one has to take into account that at the pH established by the citric acid only a part of the added chlorite appears in its protonated form as chlorous acid, and this fact makes the calculations rather complicated. " {Discussion includes Chloric acid, HClO3--an oxoacid of chlorine, and the formal precursor of chlorate salts.}

What are the appropriate concentrations of Chlorine Dioxide for sanitizing? - posted in Cleaning, Sanitation & Waste Management: Hello All, My facility recently switched to Chlorine Dioxide from Sodium Hypochlorite and there was some confusion in regards to the appropriate concentrations for sanitizing. Our chemical distributor and I set our automated mixing unit up for potable water, which is regulated at 2-5 PPM, which did not fly with our QA Supervisor. Some miscommunication occu...

"The solution is stable under neutral to slightly acidic conditions but will decay under more acidic conditions which can be prevented by adding a small amount of alkalinity (

(2014) Chlorine dioxide (CAS 10049-04-4) is a strong oxidizing agent, bactericide, fungicide, algicide, and antiseptic. "

**** {for Historical reference} "OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force." Rats exposed to 0.1-ppm concentrations of chlorine dioxide for 10 weeks at five hours daily showed no adverse effects from exposures. Other data in animals are not available."

{Company that purchased Alcide chlorine dioxide company (formerly owned by Howard Alliger???)} Research & Development, Experts, etc

{High efficiency, on-site generation} "PURATE is a blend of 40% sodium chlorate (active ingredient) and 8% hydrogen peroxide (stabilizer) with the balance being water. The reduction of sodium chlorate with hydrogen peroxide under acidic conditions produces chlorine dioxide (ClO2). It’s made easy with our pre-blended PURATE solution." "Competitors - Low Efficiency: Some chlorite-based generators can achieve 95% efficiency when properly calibrated. However, three-chemical generators (sodium chlorite + hypochlorite + HCl) quickly lose performance and require frequent adjustments and calibrations. As a result, they typically operate with lower efficiency. One particular chlorite technology (sodium chlorite + HCl) can operate with high efficiency but with a low yield. Inherent in the chemistry is the need to use 5 molecules of sodium chlorite to produce 4 molecules of ClO2, making 80% the maximum possible yield. Because of low yields, this technology is economically limited to small accounts, typically less than 1 kg/hr." *****"PURATE and sulfuric acid are NOT covered chemicals under Process Safety Management (PSM). Even though ClO2 is a covered chemical, it is generated on site and used immediately, so the threshold quantity (TQ) is never even approached. "

"...Because hypochlorite (ClO−) is an intermediate occurring in the course of the reaction mechanism, similar experiments were carried out with solutions of sodium hypochlorite (NaClO) at alkaline and acidic pHs. Electron paramagnetic re...

"during the reaction at pH 8 revealed that 2 mol of chlorite are liberated for every 1 mol of oxidized nonphenolic lignin model compound formed, consistent with two consecutive one-electron-transfer processes. In contrast, the low-pH reactions produced mostly ring oxidation products and chlorinated organic material, accompanied by increased levels of hypochlorous acid. The transient hypochlorous acid rapidly reacted with chlorite to generate chloride ions, with a maximum chloride formation at pH 4. Chlorate formation was shown to increase with increasing reaction pH. These results are in contrast to those previously reported for reactions with wood pulps and are explained on the basis of the slow reaction kinetics of nonphenolic lignin moieties as compared to phenolic ones, thereby enabling hypochlorous acid to react with chlorine dioxide to produce chlorate."

"Chlorine dioxide is 2.6 times more powerful per ppm than Chlorine. Chlorine Dioxide has a lower oxidation potential and does not hydrolyse to form an acid, and therefore is less corrosive."

Aims: Daily exposure to 100 p.p.m. chlorine dioxide of single species and binary biofilms of dairy‐associated Bacillus cereus DL5 and Pseudomonas fluorescens M2, attached to stainless steel surfaces...

*****Recently it was shown that free available chlorine (FAC) is formed during the oxidation of organic compounds with ClO2. To investigate the moieties in natural organic matter..."

*****!!!** [Murine Coronavirus A59 might be considered a suitable surrogate test virus for SARS-CoV-2 per ???]