Kinetics and Mechanism of Catalytic Decomposition and Oxidation of Chlorine Dioxide by the Hypochlorite Ion

Csordás, Viktor; Bubnis, Bernie; Fábián, István; Gordon, Gilbert

doi:10.1021/ic001106y

Cited by 33 publications

(32 citation statements)

References 38 publications

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“…25 Very recently, the role of Cl 2 O 3 in the hypochlorite-chlorine dioxide reaction has been discussed. 26 We reintroduce Cl 2 O 3 formation for three reasons. First, it is well-known 27 that the fast reversible equilibrium process takes place in aqueous solutions of HOCl, and the third-order decomposition of hypochlorous acid into chlorate and chloride is explained 28 by the further reaction of the anhydride Cl 2 O with HOCl as the rate-determining step.…”

Section: Discussionmentioning

confidence: 99%

“…26 Hong and Rapson noted that their mechanism contained an autocatalytic sequence of steps even though the S-shaped kinetics curve characteristic of autocatalysis was not observed. Their sequence is reaction 9 followed by two additional reactions: reverse of chlorine hydrolysis to produce chlorine (k r ) and consumption of chlorine by chlorous acid (k c ).…”

Section: Discussionmentioning

confidence: 99%

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Kinetics and Mechanism of the Decomposition of Chlorous Acid

et al. 2003

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The kinetics of decomposition of aqueous chlorous acid has been reinvestigated at pH 0.7-1.9, ionic strength 1.0 M (HSO 4 -/SO 4 2-), and temperature 25.0 ( 0.1°C. Optical absorbances were collected in the 240-450 nm wavelength range for up to ∼90% decomposition for time series lasting as long as 2 days. The number of absorbing species was investigated by matrix rank analysis; no absorbing intermediate was formed in significant concentration during the decomposition. Of the many mechanistic models tested, the one that fit best included the following reactive intermediates: HOCl, explains the variation in stoichiometric ratio as well as the maximum observed in the initial rate of ClO 2 formation as a function of pH. The kinetics of chlorous acid decomposition cannot be quantitatively fit through the last stages of the reaction without postulating a first-order decomposition. Scission of chlorous acid to give short-lived hydroxyl and chlorine-(II) monoxide is a plausible route for this process. A set of best-fit and literature-derived parameters is presented for the complete mechanism.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Kinetics and Mechanism of the Decomposition of Chlorous Acid

et al. 2003

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“…The latter reaction becomes significant at higher pH, indicating that hypochlorite ion is the active species in the hypochlorite-chlorine dioxide reaction. 8 Initial Rate Studies. Because the only absorbing species in the given wavelength range is • ClO 2 , dA/dt is directly proportional to d[ • ClO 2 ]/dt.…”

Section: Stoichiometrymentioning

confidence: 99%

Kinetics and Mechanism of the Chlorine Dioxide-Tetrathionate Reaction

2003

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The chlorine-dioxide-tetrathionate reaction was studied spectrophotometrically in the pH range 4.55-5.55 at 25.0 ( 0.2 °C and 0.5 M ionic strength adjusted with sodium acetate as a buffer component. The stoichiometry was found to be S 4 O 6 2-+ 4 • ClO 2 + 5H 2 O f 4SO 4 2-+ ClO 3 -+ 3Cl -+ 10H + with small deviations at high excess of chlorine dioxide with no chloride ion initially present. The initial presence of chloride not only affects the stoichiometry but also accelerates the reaction. A 14-step mechanism, including four known and two newly proposed intermediates, is suggested to describe the observed behavior of the system.

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“…Furthermore, Cl 2 addition did not affect the formation of ClO 2 – . Therefore, these increases in ClO 3 – are mainly attributed to the reaction of hypochlorous acid with ClO 2 (Uzun et al 2016, Kormanyos et al 2008, Csordas et al 2001). Overall, simultaneous use of Cl 2 and ClO 2 may be beneficial to control NDMA and THMs; however, this practice may result in the formation of ClO 3 – in addition to ClO 2 – in distribution systems.…”

Section: Resultsmentioning

confidence: 99%

The Removal of N‐Nitrosodimethylamine Formation Potential in Drinking Water Treatment Plants

2017

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A long‐term (>18 months), systematic investigation was conducted to examine (1) the removal of N‐nitrosodimethylamine (NDMA) formation potential (FP) by different treatment processes under various operational conditions at nine water treatment plants in South Carolina, and (2) the occurrence of NDMA in their distributions systems. Average NDMA FP removal by alum clarification ranged from 12 to 30% during different seasons and weather conditions. Powdered activated carbon addition improved the removal of NDMA FP, especially at high doses (>4 mg/L). The use of oxidants (i.e., chlorine [Cl2] and chlorine dioxide [ClO2]), especially simultaneous application, enhanced the removal of NDMA FP and lowered the NDMA concentration in the distribution systems to <10 ng/L. However, simultaneous application of ClO2 and Cl2 led to the formation of elevated levels of chlorate. The average NDMA FP reduction by reverse osmosis and microfiltration was 81 and 7%, respectively. The overall NDMA FP removal efficiencies between raw and finished water ranged between 40 and 59%.

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Kinetics and Mechanism of Catalytic Decomposition and Oxidation of Chlorine Dioxide by the Hypochlorite Ion

Cited by 33 publications

References 38 publications

Kinetics and Mechanism of the Decomposition of Chlorous Acid

Kinetics and Mechanism of the Decomposition of Chlorous Acid

Kinetics and Mechanism of the Chlorine Dioxide-Tetrathionate Reaction

The Removal of N‐Nitrosodimethylamine Formation Potential in Drinking Water Treatment Plants

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