Steady state concentrations of the phototransient hydrated electron in natural waters

Breugem, P.; Noort, Paul van; Velberg, Sabrina; Wondergem, Erik; Zijlstra, Jelle

doi:10.1016/0045-6535(86)90037-8

Cited by 13 publications

(10 citation statements)

References 19 publications

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“…Thermal deactivation was a dominant process (97%-99%), and only 1%-3% of energy would be transferred to an excited triplet state, most of which was involved in formation of '0 2 , In an aqueous solution of HA, Takahashi et al (1988) confirmed the formation of OH', 02H·, and '0 2 in the presence of O 2 by ESR measurements using spin-trapping reagents. Photoinduced generation of e~q from natural waters also has been confirmed by its conversion to OH· with N 20 (Thomas -Smith and Blough 2001) , and the steady-state concentration of e~q was estimated to be approximately 1.1 x 10-17 M (Breugem et al 1986). Photoinduced generation of e~q from natural waters also has been confirmed by its conversion to OH· with N 20 (Thomas -Smith and Blough 2001) , and the steady-state concentration of e~q was estimated to be approximately 1.1 x 10-17 M (Breugem et al 1986).…”

Section: F Photophysical and Photochemical Processes Of Soil Componentsmentioning

confidence: 88%

Reviews of Environmental Contamination and Toxicology

2004

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Section: F Photophysical and Photochemical Processes Of Soil Componentsmentioning

confidence: 88%

Reviews of Environmental Contamination and Toxicology

2004

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“…While e -(aq) has been a known product of water radiolysis for more than 50 years (Herbert and Coons, 2017), it can also be produced in surface waters by the interaction of sunlight with constituents of DOM (Thomas- Smith and Blough, 2001). It appears that the lifetime of the e -(aq) in the DOM phase is sufficient for its reaction with hydrophobic compounds sorbed into the DOM phase (Breugem et al, 1986). Due to the hydrophobic nature of SCCPs, with estimated octanol-water partition coefficients (Kow) between 9×10 4 and 3×10 7 (Glüge et al, 2013), these compounds have the potential to be degraded by this mechanism.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Degradation of Short-Chain Chlorinated Paraffins in Aqueous Solution by Hydrated Electrons and Hydroxyl Radicals

DiMento

Tusei

Aeppli

2022

Preprint

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Short-chain chlorinated paraffins (SCCPs) are a complex mixture of polychlorinated alkanes (C10-C13, chlorine content 40-70%), and have been categorized as persistent organic pollutants. However, there are knowledge gaps about their environmental degradation, particularly the effectiveness and mechanism of photochemical degradation in surface waters. Photochemically-produced hydrated electrons (e-(aq)) have been shown to degrade highly chlorinated compounds in environmentally-relevant conditions more effectively than hydroxyl radicals (·OH), which can degrade a wide range of organic pollutants. This study aimed to evaluate the potential for e-(aq) and ·OH to degrade SCCPs. To this end, the degradation of SCCP model compounds was investigated under laboratory conditions that photochemically produced e-(aq) or ·OH. Resulting SCCP degradation rate constants for e-(aq) were on the same order of magnitude as well-known chlorinated pesticides. Experiments in the presence of ·OH yielded similar or higher second-order rate constants. Trends in e-(aq) and ·OH SCCP model compounds degradation rate constants of the investigated SCCPs were consistent with that of other chlorinated compounds, with higher chlorine content producing in higher rate constants for e-(aq) and lower for ·OH. Above a chlorine:carbon ratio of approximately 0.6, the e-(aq) second-order rate constants were higher than rate constants for ·OH reactions. Results of this study furthermore suggest that SCCPs are likely susceptible to photochemical degradation in sunlit surface waters, facilitated by dissolved organic matter that can produce e-(aq) and ·OH when irradiated.

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“…48 It appears that the lifetime of the e -(aq) in the DOM phase is sufficient for its reaction with hydrophobic compounds sorbed by DOM. 49 Due to the hydrophobic nature of SCCPs, with estimated octanol-water partition coefficients (Kow) between 9x10 4 and 3x10 7 , these compounds have the potential to be degraded by this mechanism. 50 However, the reactivity of e -(aq) towards SCCPs has not yet been systematically investigated.…”

Section: Introductionmentioning

confidence: 99%

“…M 49,71 have been reported. However, since the lifetime of e -(aq) has been estimated to be much longer in a DOM microenvironment with different characteristics (e.g., lower O2) than the bulk aqueous solution, 91,92 DOM is expected to facilitate SCCP photodegradation in the environment.…”

mentioning

confidence: 99%

Photochemical Degradation of Short-Chain Chlorinated Paraffins in Aqueous Solution by Hydrated Electrons and Hydroxyl Radicals

DiMento¹,

Tusei²,

Aeppli³

2020

Preprint

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<p>Short-chain chlorinated paraffins (SCCPs) are a complex mixture of polychlorinated alkanes (C10-C13, chlorine content 40-70%). While these compounds are categorized as persistent organic pollutants, there are knowledge gaps about their environmental degradation, particularly the effectiveness and mechanism of photochemical degradation in surface waters. Photochemically-produced hydrated electrons (e-(aq)) have been shown to degrade highly chlorinated compounds in environmentally-relevant conditions more effectively than hydroxyl radicals (·OH), which can degrade a wide range of organic pollutants. This study aimed to evaluate the potential for e-(aq) to degrade SCCPs, and compare this reaction to ·OH-mediated degradation. To this end, the degradation of SCCP model compounds was investigated under laboratory conditions that photochemically produced e-(aq) or ·OH. Resulting SCCP degradation rate constants for e-(aq) were on the same order of magnitude as well-known chlorinated pesticides. Experiments in the presence of ·OH yielded similar or higher second-order rate constants. By compiling literature data for a wide range of chlorinated compounds, it was found that higher chlorine content results in higher rate constants for e-(aq) and lower for ·OH. Above a composition of approximately 60 % Cl, the e-(aq) second-order rate constants were higher than rate constants for ·OH reactions. The results of this study imply that SCCPs are susceptible to photochemical degradation in the environment, facilitated by dissolved organic matter and other sources of reactive intermediates in sunlit surface waters.<br></p>

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Steady state concentrations of the phototransient hydrated electron in natural waters

Cited by 13 publications

References 19 publications

Reviews of Environmental Contamination and Toxicology

Reviews of Environmental Contamination and Toxicology

Photochemical Degradation of Short-Chain Chlorinated Paraffins in Aqueous Solution by Hydrated Electrons and Hydroxyl Radicals

Photochemical Degradation of Short-Chain Chlorinated Paraffins in Aqueous Solution by Hydrated Electrons and Hydroxyl Radicals

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