Kinetics of iohexol degradation by ozonation and formation of DBPs during post-chlorination

Hu, Chen-Yan; Du, Yifan; Lin, Yi-Li; Hua, Shuang-Jing; Hou, Yuan-Zhang; Deng, Yan-Guo; Zhang, Ji-Chen; Ren, Si-Cheng; Dong, Cheng-Di; Chen, Chiu-Wen; Wu, Chung‐Hsin

doi:10.1016/j.jwpe.2020.101200

Cited by 18 publications

(4 citation statements)

References 51 publications

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“…At a solution pH of 6such as in the current experimental conditionsthe relatively low OH – ion concentration, together with the low rate constant of ozone degradation by hydroxide ions (1.9 M –1 s –1 ), results in dominating the direct reaction with CBZ. For less ozone-reactive compounds (such as IHX), however, the degradation was likely driven by the indirect mechanism …”

Section: Resultsmentioning

confidence: 99%

Catalytic Ozonation Using MnO₂-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Yecheskel,

Shreim,

Ying

et al. 2024

Environ. Sci. Technol. Lett.

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This study demonstrates the use of a MnO 2 -coated gas-permeable membrane for efficient radical delivery to water. MnO 2 of various morphologies� including nanowires (NW), nanosheets (NS) and nanoflowers (NF)�were synthesized, characterized, and evaluated according to their catalytic ozonation. In the presence of dissolved ozone, all forms of suspended MnO 2 resulted in elevated hydroxyl radical exposure but still differed across morphologies. MnO 2 NS resulted in a more efficient catalytic ozonation per mass and was thus synthesized on gas-permeable membrane tubes as a proof-of-concept. Polydimethylsiloxane (PDMS) membrane tubing was used as a platform, as it has been shown to enable effective passive diffusion of ozone driven by concentration gradients. The coated membrane allowed direct hydroxyl radical generation in a two-step process. First, the gaseous ozone passes through the inner side of the membrane and is delivered as dissolved ozone at the outer layer (i.e., to the solution). Second, once the dissolved ozone comes into contact with the deposited MnO 2 NS layer, it immediately converts to radicals, allowing for an increase of up to 43% removal of ozone-resistant compounds without additional chemicals. Overall, direct hydroxyl radical delivery using MnO 2 -enabled membranes may offer a new opportunity for effective catalytic ozonation water treatment applications.

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Section: Resultsmentioning

confidence: 99%

Catalytic Ozonation Using MnO₂-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Yecheskel,

Shreim,

Ying

et al. 2024

Environ. Sci. Technol. Lett.

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“…Both by-products are highly genotoxic and cytotoxic in mammalian cells [ 16 ]. Furthermore, ozonation of IHX in the presence of bromide enhances DBP formation [ 17 ]. Ecosar acute toxicity results showed increased toxicity of the TPs to fish and Daphnia compared to the parent compound, except ID851, which showed decreased toxicity ( Table S1 in Supplementary Materials ).…”

Section: Resultsmentioning

confidence: 99%

Pharmaceutical Transformation Products Formed by Ozonation—Does Degradation Occur?

2023

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The efficiency of an advanced oxidation process (AOP) using direct and indirect ozonation for the removal of pharmaceutical residues from deliberately spiked deionized water was examined. Both direct and indirect ozonation demonstrated 34% to 100% removal of the parent compounds. However, based on the products’ chemical structure and toxicity, we suggest that despite using accepted and affordable ozone and radical concentrations, the six parent compounds were not fully degraded, but merely transformed into 25 new intermediate products. The transformation products (TPs) differed slightly in structure but were mostly similar to their parent compounds in their persistence, stability and toxicity; a few of the TPs were found to be even more toxic than their parent compounds. Therefore, an additional treatment is required to improve and upgrade the traditional AOP toward degradation and removal of both parent compounds and their TPs for safer release into the environment.

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“…In sum, the ozonation degradation of diatrizoate fitted the second-order kinetics well, one order in ozone concentration and one order in diatrizoate concentration. The relationship between k obs and k app can be expressed (Equation ( 5)) and calculated as 0.03768 L (min mg) À1 , which is higher than that of iohexol degradation during ozonation (Hu et al 2020a).…”

Section: Kinetics Of Diatrizoate Degradation During Ozone Oxidationmentioning

confidence: 99%

“…The molecular structures of ICM consist of 2,4,6-triiodinated benzoic derivatives, and their molecular weights vary between 600 and 900 Da (Jeong et al 2017). The structures of ICM are very stable and cannot be effectively removed by traditional water treatment processes (Hu et al 2020a). Therefore, trace amounts of ICM are commonly detected in surface waters (Duirk et al 2011;Kormos et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of diatrizoate degradation by ozone and the formation of disinfection by-products in the sequential chlorination

Ren

Lin³

et al. 2021

Journal of Water Reuse and Desalination

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In this study, we studied the degradation kinetics of a common iodine contrast agent, diatrizoate, by ozone and the formation of disinfection by-products (DBPs) in the sequential chlorination. Effects of ozone concentration, solution pH, and bromide concentration on diatrizoate degradation were evaluated. The results indicate that diatrizoate can be effectively degraded (over 80% within 1 h) by ozone, and the degradation kinetics can be well described using the pseudo-first-order kinetic model. The pseudo-first-order rate constant (kobs) of diatrizoate degradation significantly increased with increasing ozone concentration and decreasing bromide concentration. The kobs kept increasing with the increase of pH value and reached a maximum of 6.5 (±0.05) × 10−2 min−1 at pH 9. As the ozone concentration gradually increased from 0.342 to 1.316 mg/L, the corresponding kobs of diatrizoate degradation increased from 1.76 (±0.20) × 10−3 to 4.22 (±0.3) × 10−2 min−1. The bromide concentration exhibited a strong inhibitory effect on diatrizoate degradation because of the competition for ozone with diatrizoate. Trichloromethane was the only detected DBP in the subsequent chlorination in the absence of bromide. However, in the presence of bromide, six other DBPs were detected, and bromochloroiodomethane and tribromomethane became the major products with concentrations 1–2 orders higher than those of the other DBPs. In order to provide safe drinking water to the public, water should be maintained at circumneutral pH values and low bromine concentrations (<5 μM) before reaching the chlorine disinfection process to effectively control the formation of DBPs.

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Kinetics of iohexol degradation by ozonation and formation of DBPs during post-chlorination

Cited by 18 publications

References 51 publications

Catalytic Ozonation Using MnO₂-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Catalytic Ozonation Using MnO₂-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Pharmaceutical Transformation Products Formed by Ozonation—Does Degradation Occur?

Kinetics of diatrizoate degradation by ozone and the formation of disinfection by-products in the sequential chlorination

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Kinetics of iohexol degradation by ozonation and formation of DBPs during post-chlorination

Cited by 18 publications

References 51 publications

Catalytic Ozonation Using MnO2-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Catalytic Ozonation Using MnO2-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Pharmaceutical Transformation Products Formed by Ozonation—Does Degradation Occur?

Kinetics of diatrizoate degradation by ozone and the formation of disinfection by-products in the sequential chlorination

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Catalytic Ozonation Using MnO₂-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals

Catalytic Ozonation Using MnO₂-Enabled Membranes: Toward Direct Delivery of Hydroxyl Radicals