Chemical & Biological Dynamics

"[To generate chlorine dioxide:] 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." "The chemical behavior and oxidation characteristics of aqueous chlorine dioxide are not well understood because of the difficulty in differentiating aqueous chlorine-containing species."

{Related to Solumium chlorine dioxide, Hungary}

"A case study on Fuller's Brewery [which implemented a chlorine dioxide dosing system] who enlisted our expertise and unique sensor technology to keep their leading product natural and chemical free." "Our disposable sensor technology utilises chronoamperometry which eliminates the interferences typically associated with colorimetric methods. As colorimetric test methods rely on light transmission for the test function, they do not tolerate highly coloured or turbid samples. Chronoamperometry does not rely on light or colour and therefore overcomes these challenges associated with reagent-based testing."

"Chlorine dioxide is regularly used in drinking water treatment. Sometimes as a pre-treatment for metal removal from the raw water entering a treatment plant, but more commonly at the end of the distribution network to control specific issues such as pseudomonas and Legionella." "Kemio uses single use disposable sensors to generate rapid and reliable results for both chlorine dioxide and chlorite. Suitable for all sample types, Kemio can be used on samples which are turbid or discoloured. Photometers are a well known method for testing for measuring chlorine dioxide. Available in both a single test format with our ClO2 meter, or as a test on our multiparameter photometer, 7500 Photometer, inclusive of over 80 test methods. Both photometers utilise the DPD method, the original test method formulated by Palintest’s very own Dr Palin."

****!!!!**** {Includes novel approach for using chlorine dioxide to spray area, as classified for stored potable water} "certified organic by OMRI and Kosher by OU." "Oxine may be used as a primary water disinfectant in municipal water at levels of 0.5 ppm and in stored potable water at levels of 5.0 ppm." "Bacterial, mold and odor control is easily restored by an initial application of activated Oxine, from 200 to 500 ppm, depending on the severity of the problem, sprayed onto the wall and floors. Follow this initial application with a periodical maintenance dosage of 100 ppm unactivated" "The filler head assemblies are considered food contact surfaces..." ***** "Low dose applications of Oxine, misted onto the filler assembly during short scheduled breaks in the production day, have proven to be of considerable benefit."

{Note: Chlorinedioxide's characteristics are misrepresented here as being similar to sodium hypochlorites'}

****!!!!**** {Instructions for preparing solutions} "Method I produces a material equivalent to that produced by most commercial chlorine dioxide generators. Method II produces a reagent grade, chlorine dioxide solution with no free chlorine and is used for instrument standards and for studies where free chlorine would interfere." "to prepare low concentration (1000 ppm), chemically pure, chlorine dioxide solutions... Chlorine dioxide (ClO2) is produced by the acidification of sodium chlorite (NaClO2) solution with sulfuric acid (H2SO4): 4NaClO2 + 2H2SO4 ---- 2ClO2 + HCl + HClO3 + 2Na2SO4 + H2O Chlorine dioxide is removed from the reaction flask solution as gas by air stripping, purified by scrubbing with sodium chlorite solution and recovered by absorbing in chilled deionized (DI) water."

" with a patented extraction process, raw meth- anol can be purified into commercial-grade biomethanol, which can either be sold for additional revenue, or used in the chlorine dioxide (ClO2) generation process. Methanol currently used in the ClO2 generator is one of the last fossil-based chemicals prohibiting the establishment of a fossil-free pulp mill operation."

"The SVP (single vessel process) chlorine dioxide process family consists of a number of similar processes based on the same equipment configuration. It is relatively easy to switch from one to the other. The different processes are distinguished from each other by use of different reducing agents and acids for converting sodium chlorate (NaClO ), to chlorine3 dioxide (ClO ). The most common process today is 2 the SVP-LITE process based on the use of methanol (CH OH)."

"In simple terms, pH is the concentration of acid protons [H+]. On the other hand, the alkalinity of a solution is its ability to neutralize acids. Alkalinity consists of ions that incorporate acid protons into their molecules so that they are not available as a free acid that can lower the pH. This is known as buffering." "Higher temperature... slightly increasing the carbonate to bicarbonate ratio. At the same time, the acid (H+) concentration increases slightly which causes a slight drop in pH. This means that a warmer solution can have better buffering capacity despite a lower pH."

"determined the products formed in the reaction of ClO2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair."

Amino acids, proteins, and peptides are found ubiquitously in waters. They can form harmful byproducts during water treatment by reaction with..."

Chapter sections: Calculating Concentration of CDG. ClO2 as a Surface Sanitizer. ClO2 Use in the Produce Industry

2020. "Treatments of wastewater and fresh produce"

"Chlorine Dioxide (DK-DOX) treatment does not affect DNA peaks whereas DPA peaks are reduced"

"The redox reactions initiated by NaClO3 and ClO2 therefore reduce the total consumption of dichromate anions (Cr 2 O 7 2− ) by organic matter present in the wastewater sample and subsequently lower the COD measurements using the dichromate method, under the test conditions. ..."

"In order to evaluate the bacterial and endotoxin contamination in the dialysis fluids of our pediatric center and the effectiveness of chlorine dioxide (CD) compared with a conventional method, (1) deionized water, (2) dialysate fluid, (3) basic concentrate, and (4) acid concentrate were tested in 4 dialysis machines."

"Relative humidity is the single most important factor influencing the activity of gaseous disinfectants/sterilants, such as EtO, chlorine dioxide, and formaldehyde. Water hardness (i.e., high concentration of divalent cations) reduces the rate of kill of certain disinfectants because divalent cations (e.g., magnesium, calcium) in the hard water interact with the disinfectant to form insoluble precipitates 1" "Most commonly, interference occurs by a chemical reaction between the germicide and the organic matter resulting in a complex that is less germicidal or nongermicidal, leaving less of the active germicide available for attacking microorganisms. Chlorine and iodine disinfectants, in particular, are prone to such interaction. Alternatively, organic material can protect microorganisms from attack by acting as a physical barrier... These and other studies show the protection by inorganic contaminants of microorganisms to all sterilization processes results from occlusion in salt crystals" "long-term use can damage the outer plastic coat of the insertion tube" "chlorine dioxide solutions at either 600 ppm or 30 ppm killed Mycobacterium avium-intracellulare within 60 seconds after contact but contamination by organic material significantly affected the microbicidal properties" " In 1986, a chlorine dioxide product was voluntarily removed from the market when its use caused leakage of cellulose-based dialyzer membranes, which allowed bacteria to migrate from the dialysis fluid side of the dialyzer to the blood side "

Oxygen transport, oxygen storage and oxygen activation in aerobic organisms depend on the iron porphyrin moiety in heme proteins. Under fluctuating ox…

Several methods for determining residual active oxidants involved in the generation and dosing of chlorine dioxide are described, including iodometry, specific ...

This book focuses on present state of the art chemical oxidation technologies with regard to various wastewater applications. It is a valuable aid to engineers

"Compatible additives can have a chemical structure selected from the group consisting of a saturated hydrocarbon, a cyclic hydrocarbon, an aromatic, a non-ionized non-aromatic carboxylic acid, an amine, an ether, an aldehyde, a ketone, an alcohol, a quaternary ammonium salt and combinations thereof. Exemplary compatible additives include, but are not limited to, L-menthol, benzaldehyde, camphor, methone, ethyl menthane carboxamide, eucalyptol, aspartame, sodium cyclamate, sodium saccharin dihydrate, sucralose, cetylpyridinium chloride, benzoyl alcohol, propylene glycol, polyethylene glycol 400, glycerol, ethyl acetate, ethanol, hydroxypropyl methylcellulose, acetone, glycine, 1-glutamic acid, boric acid, citric acid and sodium bisulfate."

A tablet that contains a metal chlorite, a chlorine-releasing compound that releases chlorine upon contact with water, a solid acid source, a metal stearate, and a macromolecular disintegrant, with the metal stearate and the macromolecular disintegrant constituting a total of 0.3-10 wt.% of the entire tablet, makes it possible to generate a sufficient concentration of chlorine dioxide in a practical amount of time regardless of the size of the facility to be treated, is strong enough that breakage during handling, e.g. transport or packaging, does not occur, and can be produced with high yield.

****!!!!*** "Chlorine dioxide is classified by the World Health Organization as a fourth-generation A1, widely used, safe, and effective disinfectant. It is widely used in bleaching, water treatment, oil extraction, aquaculture, plants, fruits and vegetables, meat products, preservation of aquatic products, food sterilization and sterilization industries. The technology of chlorine dioxide produced by the combination reduction method is widely used in domestic papermaking related companies. In order to promote the application of chlorine dioxide, the effects of storage conditions on the stability of chlorine dioxide solution prepared by the combination reduction method and the experimental study of decomposition kinetics were studied. Experiments have shown that high temperature, high pH and high initial concentration accelerate the decomposition of chlorine dioxide solution, and the addition of sodium dihydrogen phosphate (NaH 2 PO 4 ) and dimethyl sulfoxide (DMSO) can inhibit the decomposition"

The product distribution from the decay of chlorine dioxide in basic solution changes as the ClO2 concentration decreases. While disproportionation reactions that give equal amounts of ClO2- and ClO3- dominate the stoichiometry at millimolar or higher levels of ClO2, the ratio of ClO2- to ClO3- formed increases significantly at micromolar ClO2 levels. Kinetic evidence shows three concurrent pathways that all exhibit a first-order dependence in [OH-] but have variable order in [ClO2]. Pathway 1 is a disproportionation reaction that is first order in [ClO2]. Pathway 2, a previously unknown reaction, is also first order in [ClO2] but forms ClO2- as the only chlorine-containing product. Pathway 3 is second order in [ClO2] and generates equal amounts of ClO2- and ClO3-. A Cl2O4 intermediate is proposed for this path. At high concentrations of ClO2, pathway 3 causes the overall ClO3- yield to approach the overall yield of ClO2-. Pathway 2 is attributed to OH- attack on an oxygen atom of ClO2 that leads to peroxide intermediates and yields ClO2- and O2 as products. This pathway is important at low levels of ClO2.