Effects of Chromophoric Dissolved Organic Matter on Anthracene Photolysis Kinetics in Aqueous Solution and Ice

Malley, P.; Grossman, Jarod; Kahan, Tara F.

doi:10.1021/acs.jpca.7b05199

Cited by 25 publications

(17 citation statements)

References 50 publications

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“…Table 1 shows first order anthracene photodegradation rate constants in aqueous solution and artificial snow. In agreement with several previous studies, 13,17,36,37 though in contrast to Ref. 10, we measure a larger rate constant in the frozen sample.…”

Section: Photodegradation Kineticssupporting

confidence: 93%

“…33 If all anthracene molecules at the surface of frozen NaCl solutions are in the brine channels, we calculate anthracene concentrations on the order of -20 µM at deposition times corresponding to 50 -200% of a formal monolayer, based on a liquid volume fraction of 15% for 0.6 M NaCl solutions at −15 o C. 22 This is well above anthracene's saturation limit in room temperature DI water (~0.2 µM); 34 we have shown that the 380 nm emission peak of anthracene becomes increasingly suppressed with increasing anthracene concentration at concentrations greater than ~10 µM. 17 High anthracene concentrations in brine channels, along with salting-out due to high NaCl concentrations in the brine channels (~4 M), 35 likely explain the excimer-like anthracene emission observed at the frozen salt solution surface.…”

Section: Spectra and Mapsmentioning

confidence: 68%

“…[13][14][15][16] We have recently reported that anthracene molecules in liquid aqueous solution photodegrade much more rapidly at concentrations well above the saturation limit where spectroscopic evidence of self-association is observed than in dilute solutions, and that the photodegradation kinetics shift from 1 st to 2 nd order at these high concentrations. 17 We have hypothesized that aromatic species form clusters at ice surfaces, and that self-associated anthracene molecules in these clusters react via different mechanisms than monomeric anthracene in liquid water or at air-water interfaces. 17 However, other research groups have reported a lack of self-association of aromatic species in ice samples, supported by spectroscopic evidence and MD simulations.…”

Section: Introductionmentioning

confidence: 99%

“…17 We have hypothesized that aromatic species form clusters at ice surfaces, and that self-associated anthracene molecules in these clusters react via different mechanisms than monomeric anthracene in liquid water or at air-water interfaces. 17 However, other research groups have reported a lack of self-association of aromatic species in ice samples, supported by spectroscopic evidence and MD simulations. 18,19 The key to predicting reactivity of aromatic species (and perhaps non-aromatic species) in snow and ice may lie in elucidating the interactions of these species with each other and with their surroundings.…”

Section: Introductionmentioning

confidence: 99%

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Direct Observation of Anthracene Clusters at Ice Surfaces

2022

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Heterogeneous processes can control atmospheric composition. Snow and ice present important, but poorly understood, reaction media that can greatly alter the composition of air in the cryosphere in polar and temperate regions. Atmospheric scientists struggle to reconcile model predictions with field observations in snow-covered regions due to experimental challenges associated with monitoring reactions at air-ice interfaces, and debate regarding reaction kinetics and mechanisms has persisted for over a decade. In this work, we use wavelength-resolved fluorescence microscopy to determine the distribution and chemical speciation of the pollutant anthracene at the surfaces of environmentally relevant frozen surfaces. We show that anthracene adsorbs to frozen surfaces in monomeric form, but that following lateral diffusion, molecules ultimately reside within brine channels at saltwater ice surfaces, and in micron-sized clusters at freshwater ice surfaces; emission profiles indicate extensive self-association. We also measure anthracene photodegradation kinetics in aqueous solution and artificial snow prepared from frozen freshwater and saltwater solutions and use the micro-spectroscopic observations to explain the rate constants measured in different environments. These results resolve long-standing debates and will improve predictions of pollutant fate in the cryosphere. The techniques used can be applied to numerous surfaces within and beyond the atmospheric sciences.

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Section: Photodegradation Kineticssupporting

confidence: 93%

Section: Spectra and Mapsmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct Observation of Anthracene Clusters at Ice Surfaces

2022

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“…This indicates that the inner filter effect was negligible in our experiments. We recently reported that DOM does not greatly affect anthracene photodegradation kinetics in aqueous solution, even at concentrations much greater than those present in our Sargasso Sea water samples . The observed deviations in anthracene’s photodegradation kinetics in Sargasso Sea water from those in DI water are therefore likely primarily due to effects of halides and other heavy atoms.…”

Section: Results and Discussionmentioning

confidence: 41%

Anthracene and Pyrene Photooxidation Kinetics in Saltwater Environments

Grossman

Kowal

Stubbs

et al. 2019

ACS Earth Space Chem.

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Solutes can greatly affect pollutant photodegradation kinetics in atmospheric aqueous phases such as surface waters, atmospheric aerosols, and cloud and fog droplets. We have measured photooxidation rate constants of the polycyclic aromatic hydrocarbons (PAHs) pyrene and anthracene in aqueous solutions containing environmentally relevant concentrations of halide salts (NaCl, NaBr, and NaI) and in seawater. Chloride, bromide, and iodide did not affect pyrene photodegradation kinetics but increased anthracene photodegradation rate constants at low halide concentrations. The largest anthracene rate constant measured, in the presence of 0.2 M NaCl, was 3.4 times larger than that in deionized water. Smaller enhancements were observed in the presence of NaBr and NaI, with maximum rate constants observed at concentrations of 1 × 10 −5 and 1 × 10 −8 M, respectively. We determined that this enhancement was due to singlet oxygen ( 1 O 2 ) generation resulting from interactions between halides and electronically excited anthracene. Interactions between pyrene and halides also formed 1 O 2 , but this did not affect pyrene's observed photodegradation rate constant. At higher halide concentrations, anthracene photodegradation rate constants showed a weak negative dependence on halide concentration, likely due to quenching of anthracene's excited triplet state. Our results suggest that the fates of some PAHs in saline environments could differ from those predicted by kinetics measured in deionized water in the absence of solutes.

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Ice‐Mediated Reactions and Assemblies in Diverse Domains

Wang,

Wu,

et al. 2024

Adv Funct Materials

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In chemistry, biology, and materials science, ice‐mediated reactions and ice‐template assembly techniques are garnering increasing attention due to their unique advantages. Such approaches not only offer deep insights into the fundamental roles of ice in nature but also pave new avenues for various applications. This review comprehensively explores the mechanisms and applications of ice‐mediated reactions and assembly. It begins by examining the principles of ice‐mediated reactions, particularly how certain chemical reactions are accelerated in the micro‐environment of ice through freeze‐concentration and freeze‐potential effects, and the relationship between the surface structure and properties of ice and chemical reactions. This work then studies significant chemical reactions within the realms of environmental, biological, and materials science engineering, shedding light on the role of ice in these reactions. Furthermore, this work explores the fundamentals of ice templating in material assembly, describe the main ice‐templating methods, and highlight the ice‐templated materials along with their diverse applications. This work concludes by summarizing the prospective challenges and untapped potentials in the field of ice‐mediated reactions and assembly. This review not only accentuates the transformative impact of ice‐mediated techniques in scientific domains but also serves as an useful guide for future research initiatives and practical applications in this burgeoning field.

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Effects of Chromophoric Dissolved Organic Matter on Anthracene Photolysis Kinetics in Aqueous Solution and Ice

Cited by 25 publications

References 50 publications

Direct Observation of Anthracene Clusters at Ice Surfaces

Direct Observation of Anthracene Clusters at Ice Surfaces

Anthracene and Pyrene Photooxidation Kinetics in Saltwater Environments

Ice‐Mediated Reactions and Assemblies in Diverse Domains

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