Improved Ozonation in Aqueous Systems

Nakayama, S.; Esaki, Kenji; Namba, Kosuke; Taniguchi, Yoshihiro; Tabata, Norikazu

doi:10.1080/01919517908550839

Cited by 41 publications

(13 citation statements)

References 2 publications

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“…An applicable technology to decompose persistent organic matter such as 1,4-dioxane is the advanced oxidation technology, which is a technology using hydroxyl radical (·OH) as an oxidant. Several types of ozone-based advanced oxidation technologies have been proposed like ozonation with UV irradiation (Peyton and Glaze, 1988), ozonation with the addition of hydrogen peroxide (Nakayama et al, 1979) and ozonation combined with electrolysis (Kishimoto et al, 2005(Kishimoto et al, , 2010a. These processes successfully enhance the oxidation potential of ozone treatment.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Effect of Several Iron Species on Ozonation

Kishimoto

Ueno

2012

J. of Wat. ^|^ Envir. Tech.

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Section: Introductionmentioning

confidence: 99%

Catalytic Effect of Several Iron Species on Ozonation

Kishimoto

Ueno

2012

J. of Wat. ^|^ Envir. Tech.

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“…O 2 -) are assumed to be produced by the reaction of ozone and perhydroxyl ion (HO 2 -) at the initiation reaction, the intermediates in the chain reaction cycle such as HO 3 and O 3 OH radical were neglected in this newly developed model. That is, this model considered equations [1], [2], [4], [5], [9], [18] and [21]. The formation of hydrogen peroxide by decomposition of organic compounds was also neglected.…”

Section: Simulation Modelmentioning

confidence: 99%

“…In spite of the competitiveness and complication of the radical reactions and the difficulty of monitoring radicals, it is indispensable to understand the radical reaction rates and kinetics for upgrading the design and operation technology of the ozone-hydrogen peroxide treatment. Some investigations into the application of this treatment method have previously been carried out by Nakayama et al (1979) and Hango et al (1981) as pioneers. They reported characteristic phenomena in this treatment process, i.e., an improvement in the ozone absorption efficiency, as well as the decomposition of refractory compounds.…”

Section: Introductionmentioning

confidence: 98%

New Approach for Optimization of Ozone-Hydrogen Peroxide Water Treatment

Yasunaga

Furukawa

Kawaai

et al. 2006

Ozone: Science & Engineering

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A new radical reaction model for the ozone-hydrogen peroxide treatment, which was much simpler than current models such as SBH and TFG, has been developed by computer simulation in order to investigate a new reactor for this treatment process. It was revealed that the simulation results by using this new developed model were in good agreement with the experimental results in terms of the variation in the concentration of ozone in both gas and liquid phase, hydrogen peroxide and TOC, indicating the appropriateness of this new model. Thus, it was considered that this new model was very convenient for analysis of radical reactions because of its simplicity.

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“…However, this requires the post-treatment of copious amounts of residual iron sludge. Ozone-based processes involve ozonation with ultraviolet (UV) light irradiation [10], ozonation with the addition of H2O2 [11], ozoneelectrolysis processes [12], etc. However, ozone-based processes require an ozone generator, an oxygen generator, and an ozone decomposer.…”

Section: Introductionmentioning

confidence: 99%

Effect of pH and molar ratio of pollutant to oxidant on a photochemical advanced oxidation process using hypochlorite

Kishimoto

Nishimura

2015

Environmental Technology

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Ultra violet (UV)-photolysis of hydrogen peroxide (H2O2) is a conventional advanced oxidation process (AOP) and is advantageous in its simplicity, although H2O2 is costly. Accordingly, we tried to substitute H2O2 by hypochlorite in the photochemical AOP, and discussed the effect of pH and the molar ratio of a pollutant to hypochlorite on the process using 1,4-dioxane as a model pollutant. The photochemical treatment of hypochlorite solutions at a wavelength of 254 nm under various pH values revealed that the UV-photolysis of hypochlorous acid (HOCl) species mainly contributed to hydroxyl radical (•OH) production. The reaction efficiency, as defined by the molar ratio of removed 1,4-dioxane to consumed hypochlorite, deteriorated under higher pH levels due to the stronger radical scavenging effect of hypochlorite ion (ClO(-)) as compared to that of HOCl. The optimal pH for the UV-photolysis of hypochlorite as an AOP was found to be in the range of 3-6. The reaction efficiency at a high molar ratio of initial 1,4-dioxane to initial hypochlorite exceeded 100%, which was caused by the regeneration of HOCl from photochemically generated chlorine radicals (•Cl). Finally, the overall reaction of the UV-photolysis of HOCl was proposed on the basis of the radical reactions that were related to chlorine species, which suggested that the UV-photolysis of 1 mmol of HOCl stoichiometrically produced 2 mmol of •OH. Since the use of liquid chlorine is more economical than that of H2O2, the substitution of HOCl for H2O2 in the photochemical AOP was concluded to be feasible from the viewpoints of both stoichiometry and chemical costs.

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Improved Ozonation in Aqueous Systems

Cited by 41 publications

References 2 publications

Catalytic Effect of Several Iron Species on Ozonation

Catalytic Effect of Several Iron Species on Ozonation

New Approach for Optimization of Ozone-Hydrogen Peroxide Water Treatment

Effect of pH and molar ratio of pollutant to oxidant on a photochemical advanced oxidation process using hypochlorite

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