Recalcitrance of cyanuric acid to oxidative degradation by OH radical: theoretical investigation

Liu, Guangyan

doi:10.1039/c4ra04687k

Cited by 10 publications

(6 citation statements)

References 27 publications

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“…could then confer its recalcitrance toward hydroxyl radical attack. In the same way, cyanuric acide is well known as recalcitrant to hydroxyl radical oxidation due to the electron deficiency of the triazine ring linked to the higher electronegativity of nitrogen compared to that of carbon (Liu, 2014).…”

Section: Evolution Of Mtz Degradation and Mineralizationmentioning

confidence: 99%

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products

et al. 2018

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In this study, the monitoring of reactive oxygen species and the regeneration of the ferrous ions catalyst were performed during electro-Fenton (EF) process to highlight the influence of operating parameters. The removal of metronidazole (MTZ) was implemented in an electrochemical mono-compartment batch reactor under various ranges of current densities, initial MTZ and ferrous ions concentrations, and pH values. It was found that under 0.07 mA cm, 0.1 mM of ferrous ions and pH = 3, the efficiency of 100 mg L MTZ degradation and mineralization were 100% within 20 min and 40% within 135 min of electrolysis, respectively. The highest hydrogen peroxide and hydroxyl radical concentrations, 1.4 mM and 2.28 mM respectively, were obtained at 60 min electrolysis at 0.07 mA cm. Improvement of the biodegradability was reached from 60 min of electrolysis with a BOD/COD ratio above 0.4, which was reinforced by a respirometric study, that supports the feasibility of coupling electro-Fenton and biological treatment for the metronidazole removal.

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Section: Evolution Of Mtz Degradation and Mineralizationmentioning

confidence: 99%

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products

et al. 2018

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“…43,44 However, whether the radicals generated in the UV 222 /Cl-cyanurates AOP increase the concentrations of byproducts remains unknown. Although cyanuric acid and Cl-cyanurates are inert to radicals (HO • , Cl • , and ClO • ), 37,45 whether UV 222 irradiation can destruct cyanuric acid and Clcyanurates to generate undesired byproducts remains to be explored.…”

Section: Introductionmentioning

confidence: 99%

A High-Radical-Yield Advanced Oxidation Process Coupling Far-UVC Radiation with Chlorinated Cyanurates for Micropollutant Degradation in Water

Zhao

Shang

Yin

2023

Environ. Sci. Technol.

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Increasing the radical yield and reducing energy consumption would enhance the sustainability and competitiveness of advanced oxidation processes (AOPs) for micropollutant degradation in water. We herein report a novel AOP coupling far-UVC radiation at 222 nm with chlorinated cyanurates (termed the UV222/Cl-cyanurates AOP) for radical generation and micropollutant abatement in water. We experimentally determined the concentrations of HO•, Cl•, and ClO• in the UV222/Cl-cyanurates AOP in deionized water and swimming pool water. The radical concentrations are 10–27 times and 4–13 times, respectively, higher than those in the UV254/Cl-cyanurates AOP and the well-documented UV254/chlorine AOP under comparable conditions (e.g., same UV fluence and oxidant dosing). We determined the molar absorption coefficients and innate quantum yields of two chlorine species and two Cl-cyanurates at 222 nm and incorporated these parameters into a kinetic model. The model enables accurate prediction of oxidant photodecay rates as well as the pH impact on radical generation in the UV222/Cl-cyanurates AOP. We predicted the pseudo-first-order degradation rate constants of 25 micropollutants in the UV222/Cl-cyanurates AOP and demonstrated that many micropollutants can be degraded by >80% with a low UV fluence of 25 mJ cm–2. This work advances the fundamental photochemistry of chlorine and Cl-cyanurates at 222 nm and offers a highly effective engineering tool in combating micropollutants in water where Cl-cyanurates are suitable to use.

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“…Only H atom abstraction reactions were considered, in order to illustrate the effect of direct electron transfer on OH • reactivity, although other reaction mechanisms are likely occurring (e.g., OH • addition). Simulations with CA were chosen because it was reported to have the lowest measured reaction rate constant with OH • . ,, …”

Section: Resultsmentioning

confidence: 99%

“…Simulations with CA were chosen because it was reported to have the lowest measured reaction rate constant with OH • . 47,48,50 Results from DFT simulations determined that ΔG r = 226 kJ mol −1 for reaction 13 and ΔG r = −206 kJ mol −1 for reaction 14. These results indicated that the direct oxidation reaction to produce CA •+ allowed for a thermodynamically favorable reaction with OH • , which explained the complete mineralization of ATZ observed in our experiments.…”

Section: Mechanism For Atz and Cdn Electrochemicalmentioning

confidence: 99%

Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO₂–Ti_nO_2n–1 Electrocatalytic Reactive Electrochemical Membranes

Gayen

Chen

Abiade

et al. 2018

Environ. Sci. Technol.

138

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This research focused on improving mineralization rates during the advanced electrochemical oxidation treatment of agricultural water contaminants. For the first time, bismuth-doped tin oxide (BDTO) catalysts were deposited on Magneĺi phase (Ti n O 2n−1 , n = 4−6) reactive electrochemical membranes (REMs). Terephthalic acid (TA) was used as a OH • probe, whereas atrazine (ATZ) and clothianidin (CDN) were chosen as model agricultural water contaminants. The BDTO-deposited REMs (REM/BDTO) showed higher compound removal than the REM, due to enhanced OH • production. At 3.5 V/SHE, complete mineralization of TA, ATZ, and CDN was achieved for the REM/BDTO upon a single pass in the reactor (residence time ∼3.6 s). Energy consumption for REM/BDTO was as much as 31-fold lower than the REM, with minimal values per log removal of <0.53 kWh m −3 for TA (3.5 V/SHE), <0.42 kWh m −3 for ATZ (3.0 V/SHE), and 0.83 kWh m −3 for CDN (3.0 V/ SHE). Density functional theory simulations provided potential dependent activation energy profiles for ATZ, CDN, and various oxidation products. Efficient mass transfer and a reaction mechanism involving direct electron transfer and reaction with OH • were responsible for the rapid and complete mineralization of ATZ and CDN at very short residence times.

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Recalcitrance of cyanuric acid to oxidative degradation by OH radical: theoretical investigation

Abstract: Electron deficiency of the triazine ring makes the reactions between cyanuric acid and OH radical energetically unfavorable.

Cited by 10 publications

References 27 publications

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products

A High-Radical-Yield Advanced Oxidation Process Coupling Far-UVC Radiation with Chlorinated Cyanurates for Micropollutant Degradation in Water

Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO₂–Ti_nO_2n–1 Electrocatalytic Reactive Electrochemical Membranes

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Recalcitrance of cyanuric acid to oxidative degradation by OH radical: theoretical investigation

Abstract: Electron deficiency of the triazine ring makes the reactions between cyanuric acid and OH radical energetically unfavorable.

Cited by 10 publications

References 27 publications

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products

A High-Radical-Yield Advanced Oxidation Process Coupling Far-UVC Radiation with Chlorinated Cyanurates for Micropollutant Degradation in Water

Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO2–TinO2n–1 Electrocatalytic Reactive Electrochemical Membranes

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Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO₂–Ti_nO_2n–1 Electrocatalytic Reactive Electrochemical Membranes