An efficiency analysis for the production of chlorine dioxide by the electrolysis of brine in seawater desalination plants

Abstract A previous study by the authors evaluated the efficiency of producing multi-oxidants using anodes coated in precious metal. This study showed that a titanium anode coated in ruthenium generates the largest amount of active chlorine (chlorine dioxide). The results from the efficiency evaluation also show that DuPont Nafion N-2030 ion film is the most efficient of the diaphragms that were tested. To increase the recovery rate for ClO2, this study optimizes the composition of the anode electrolyte. Sodium chlorite is added into the brine and an electrolysis reaction is performed at 40 °C and 12 V for batch operation. The principal product is ClO2 with a maximum concentration of 1,074 mg L−1. During continuous electrolysis, when the inflow rate for the anode electrolyte is increased to 120 mL min−1, ClO2 is produced at a constant concentration of 60 mg L−1 after 30 minutes. An analysis of the multi-oxidants generated from brine to detect disinfection byproducts shows very little trichloromethane is formed, much less than the standard for total trihalomethanes in drinking water in Taiwan (0.1 mg L−1). The disinfection efficiency of the multi-oxidant produced in this study is about three times greater than that of commercial hypochlorous acid. These results show that multi-oxidant products retrieved by recycling brine from desalination plants are commercially applicable and have economic value.

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Feasibility study for the production of multi-oxidants from the desalination of seawater brine

Water Quality Research Journal ◽

10.2166/wcc.2018.160 ◽

2018 ◽

Vol 54 (3) ◽

pp. 242-248 ◽

Cited By ~ 1

Author(s):

Chiung-Ta Wu ◽

Chen-Yu Chang ◽

Yi-Ying Li ◽

Po-Hsiung Lin

Keyword(s):

Open Access ◽

Chlorine Dioxide ◽

Precious Metal ◽

Raw Material ◽

Active Chlorine ◽

Reaction Conditions ◽

Main Component ◽

Desalination Plants ◽

Multiple Oxidants ◽

Brine Salinity

Abstract The primary goals of this study are to compare the efficiency of multiple oxidants that are produced using different commercially available anodes and separators and to optimize the reaction conditions for the recovery of multiple oxidants from brine. The brine produced in the desalination plants in Taiwan is the concentrated seawater that is recovered after the reverse osmosis process. The main component in the solution is NaCl. On average, chlorine concentration is approximately 3–5% by weight, which is slightly higher than the concentration for normal seawater. This concentrated brine can be used as raw material for the electrolyte to extract mixed disinfectant solutions. This study uses different catalytic electrolyzers to compare the efficiency with which multiple oxidants are produced using anodes that are coated in precious metal. A ruthenium-coated titanium anode generates the largest amount of active chlorine (chlorine dioxide). In terms of the diaphragms that are tested, the DuPont Nafion NE-2030 ion film produces active chlorine most efficiently. If no other chemicals are added to the brine (salinity 11.3%), Cl2 (302–376 mg L−1) is the primary oxidant generated from the original brine, and ClO2 (3.7–7.2 mg L−1) is the minor product in batch electrolysis. This article has been made Open Access thanks to the kind support of CAWQ/ACQE (https://www.cawq.ca).

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Mécanisme des réactions du chlorite et du dioxyde de chlore. 1. Stoechiométrie des réactions du chlorite et cinétique en présence d'ortho-tolidine

Canadian Journal of Chemistry ◽

10.1139/v81-172 ◽

1981 ◽

Vol 59 (8) ◽

pp. 1177-1187 ◽

Cited By ~ 5

Author(s):

Guy Schmitz ◽

Henri Rooze

Keyword(s):

Chlorine Dioxide ◽

Perchloric Acid ◽

Hypochlorous Acid ◽

Chloride Ions ◽

Sodium Chlorite ◽

Kinetic Investigation ◽

Acid Solutions ◽

Fast Reaction ◽

Rate Determining Step ◽

Chlorous Acid

The relative amount of chlorine dioxide produced by the disproportionation of sodium chlorite increases as the concentrations of chlorite and chloride ions increase. It passes through a minimum when the concentration of perchloric acid varies from 2 M to 0.01 M. The fast reaction between chlorite and hypochlorous acid is a part of the mechanism of this disproportionation and its stoichiometry was also investigated. The relative amount of chlorine dioxide produced depends on the method of mixing the reactants and on the acidity. It increases if the concentration of chlorite increases and can exceed the amount predicted by:[Formula: see text]Ortho-tolidine reacts very rapidly with chlorine and with chlorine dioxide but not with chlorous acid. In perchloric acid solutions (pH < 2.5) the product of its oxidation has a considerable absorption with a maximum at 440 nm (ε = 59700 M−1 cm−1). Chlorine reacts more rapidly with ortho-tolidine than with chlorous acid. The kinetic investigation of the disproportionation of chlorous acid is thus simplified by the use of ortho-tolidine. With added chloride ions the rate determining step is HClO2 + Cl− + H+ → 2HClO with a rate constant[Formula: see text]The most reliable values for the free enthalpy of formation of oxychlorine compounds are selected from the literature.

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The Role of Catalytic Ozonation Processes on the Elimination of DBPs and Their Precursors in Drinking Water Treatment

Catalysts ◽

10.3390/catal11040521 ◽

2021 ◽

Vol 11 (4) ◽

pp. 521

Author(s):

Fernando J. Beltrán ◽

Ana Rey ◽

Olga Gimeno

Keyword(s):

Drinking Water ◽

Water Treatment ◽

Humic Substances ◽

Hypochlorous Acid ◽

Drinking Water Treatment ◽

Disinfection Byproducts ◽

Catalytic Ozonation ◽

Operating Conditions ◽

Halogen Compounds ◽

Radiation Sources

Formation of disinfection byproducts (DBPs) in drinking water treatment (DWT) as a result of pathogen removal has always been an issue of special attention in the preparation of safe water. DBPs are formed by the action of oxidant-disinfectant chemicals, mainly chlorine derivatives (chlorine, hypochlorous acid, chloramines, etc.), that react with natural organic matter (NOM), mainly humic substances. DBPs are usually refractory to oxidation, mainly due to the presence of halogen compounds so that advanced oxidation processes (AOPs) are a recommended option to deal with their removal. In this work, the application of catalytic ozonation processes (with and without the simultaneous presence of radiation), moderately recent AOPs, for the removal of humic substances (NOM), also called DBPs precursors, and DBPs themselves is reviewed. First, a short history about the use of disinfectants in DWT, DBPs formation discovery and alternative oxidants used is presented. Then, sections are dedicated to conventional AOPs applied to remove DBPs and their precursors to finalize with the description of principal research achievements found in the literature about application of catalytic ozonation processes. In this sense, aspects such as operating conditions, reactors used, radiation sources applied in their case, kinetics and mechanisms are reviewed.

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Mechanism Involving Hydrogen Sulfite Ions, Chlorite Ions, and Hypochlorous Acid as Key Intermediates of the Autocatalytic Chlorine Dioxide-Thiourea Dioxide Reaction

European Journal of Inorganic Chemistry ◽

10.1002/ejic.201500654 ◽

2015 ◽

Vol 2015 (30) ◽

pp. 5011-5020 ◽

Cited By ~ 7

Author(s):

Ying Hu ◽

Attila K. Horváth ◽

Sasa Duan ◽

György Csekő ◽

Sergei V. Makarov ◽

...

Keyword(s):

Chlorine Dioxide ◽

Hypochlorous Acid ◽

Thiourea Dioxide ◽

Chlorite Ions ◽

Sulfite Ions

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Germicidal Activity of a Chlorous Acid-Chlorine Dioxide Teat Dip and a Sodium Chlorite Teat Dip During Experimental Challenge with Staphylococcus aureus and Streptococcus agalactiae

Journal of Dairy Science ◽

10.3168/jds.s0022-0302(98)75809-6 ◽

1998 ◽

Vol 81 (8) ◽

pp. 2293-2298 ◽

Cited By ~ 8

Author(s):

R.L. Boddie ◽

S.C. Nickerson ◽

R.W. Adkinson

Keyword(s):

Staphylococcus Aureus ◽

Chlorine Dioxide ◽

Streptococcus Agalactiae ◽

Sodium Chlorite ◽

Chlorous Acid ◽

Experimental Challenge

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Tertiary amine-catalyzed generation of chlorine dioxide from hypochlorous acid and chlorite ions

Wood Science and Technology ◽

10.1007/s00226-020-01247-5 ◽

2020 ◽

Author(s):

Estefania Isaza Ferro ◽

Jordan Perrin ◽

Owain George John Dawson ◽

Tapani Vuorinen

Keyword(s):

Chlorine Dioxide ◽

Tertiary Amine ◽

Hypochlorous Acid ◽

Suitable Candidate ◽

Rate Limiting Step ◽

Limiting Step ◽

Chlorite Ions ◽

The Stability ◽

Rate Limiting

AbstractThe reaction between hypochlorous acid and chlorite ions is the rate limiting step for in situ chlorine dioxide regeneration. The possibility of increasing the speed of this reaction was analyzed by the addition of tertiary amine catalysts in the system at pH 5. Two amines were tested, DABCO (1,4-diazabicyclo[2.2.2]octane) and its derivative CEM-DABCO (1-carboethoxymethyl-1-azonia-4-aza-bicyclo[2.2.2]octane chloride). The stability of the catalysts in the presence of both reagents and chlorine dioxide was measured, with CEM-DABCO showing to be highly stable with the mentioned chlorine species, whereas DABCO was rapidly degraded by chlorine dioxide. Hence, CEM-DABCO was chosen as a suitable candidate to catalyze the reaction of hypochlorous acid with chlorite ions and it significantly increased the speed of this reaction even at low catalyst dosages. This research opens the door to a faster regeneration of chlorine dioxide and an improved efficiency in chlorine dioxide treatments.

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