Photoinduced transformation of pyridinium-based ionic liquids, and implications for their photochemical behavior in surface waters

Calza, Paola; Noè, Giorgio; Fabbri, Debora; Santoro, V.; Minero, Claudio; Vione, Davide; Medana, Claudio

doi:10.1016/j.watres.2017.05.064

Cited by 28 publications

(26 citation statements)

References 53 publications

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“…11 Therefore, a photolabile molecule in a poorly photoactive environment can have comparable (or even longer) lifetime as a photostable molecule in a photoreactive water body. 12 This issue deprives the terms "photostability" and "photolability" of part of their absolute significance.…”

Section: Introductionmentioning

confidence: 99%

Photochemistry of Surface Fresh Waters in the Framework of Climate Change

Vione

Scozzaro

2019

Environ. Sci. Technol.

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109

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Photochemical processes taking place in surface fresh waters play an important role in the transformation of biorecalcitrant pollutants and some natural compounds and in the inactivation of microorganisms. Such processes are divided into direct photolysis, where a molecule is transformed following sunlight absorption, and indirect photochemistry, where naturally occurring photosensitizers absorb sunlight and produce a range of transient species that can transform dissolved molecules (or inactivate microorganisms). Photochemistry is usually favored in thoroughly illuminated shallow waters, while the dissolved organic carbon (DOC) acts as a switch between different photochemical pathways (direct photolysis, and indirect photochemistry triggered by different transient species). Various phenomena connected with climate change (water browning, changing precipitations) may affect water DOC and water depth, with implications for the kinetics of photoreactions and the associated transformation pathways. The latter are important because they often produce peculiar intermediates, with particular health and environmental impacts. Further climate-induced effects with photochemical implications are shorter icecover seasons and enhanced duration of summer stratification in lakes, as well as changes in the flow velocity of rivers that affect the photodegradation time scale. This contribution aims at showing how the different climate-related phenomena can affect photoreactions and which approaches can be followed to quantitatively describe these variations.

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Section: Introductionmentioning

confidence: 99%

Photochemistry of Surface Fresh Waters in the Framework of Climate Change

Vione

Scozzaro

2019

Environ. Sci. Technol.

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109

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“…In contrast, very little interest has been devoted to the photochemical characterization of natural ecosystems, despite the fact that their photoreactivity can also widely vary. In fact, a photolabile molecule in a poorly photoreactive environment can have the same phototransformation kinetics as a photostable molecule in a photoreactive water body [11]. The lack of attention paid towards the photochemical functioning of the natural aquatic systems is probably due to the difficulty of extrapolating results from laboratory experiments to real outdoor conditions, which has led to an important underestimation of the environmental variability.…”

Section: Introductionmentioning

confidence: 99%

A Critical View of the Application of the APEX Software (Aqueous Photochemistry of Environmentally-Occurring Xenobiotics) to Predict Photoreaction Kinetics in Surface Freshwaters

Vione

2019

Molecules

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The APEX (aqueous photochemistry of environmentally occurring xenobiotics) software computes the phototransformation kinetics of compounds that occur in sunlit surface waters. It is free software based on Octave, and was originally released in 2014. Since then, APEX has proven to be a remarkably flexible platform, allowing for the addressing of several environmental problems. However, considering APEX as a stand-alone software is not conducive to exploiting its full potentialities. Rather, it is part of a whole ecosystem that encompasses both the software and the laboratory protocols that allow for the measurement of substrate photoreactivity parameters. Coherently with this viewpoint, the present paper shows both how to use APEX, and how to experimentally derive or approximately assess the needed input data. Attention is also given to some issues that might provide obstacles to users, including the extension of APEX beyond the simple systems for which it was initially conceived. In particular, we show how to use APEX to deal with compounds that undergo acid-base equilibria, and with the photochemistry of systems such as stratified lakes, lakes undergoing evaporation, and rivers. Hopefully, this work will provide a reference for the smooth use of one of the most powerful instruments for the modeling of photochemical processes in freshwater environments. All authors have read and agreed to the published version of the manuscript. Molecules 2020, 25, 9 2 of 34 the main ones in surface waters being chromophoric dissolved organic matter (CDOM), nitrate, and nitrite [3,4]. The irradiation of all the mentioned photosensitizers yields the photoreactive transient • OH (hydroxyl radical), which can produce another transient (CO 3 •− , the carbonate radical) upon reaction with inorganic carbon species (HCO 3 − and CO 3 2− ) [5]. Irradiated CDOM can also produce reactive triplet states ( 3 CDOM*), and the latter yield singlet oxygen ( 1 O 2 ) upon reaction with dissolved O 2 [3,6]. All the mentioned transient species ( • OH, CO 3 •− , 3 CDOM*, and 1 O 2 ) are involved to some extent in indirect pollutant phototransformation, depending on the reactivity of the given pollutant towards each transient [7,8]. Although they play a key role in indirect phototransformation of pollutants, the transients are mostly scavenged/quenched by natural water components. The latter include: (i) dissolved organic matter (DOM, either chromophoric or not), HCO 3 − and CO 3 2− in the case of • OH (plus Br − , which plays the main role in some saltwaters and in seawater); (ii) DOM again in the case of CO 3 •− ; (iii) dissolved O 2 for 3 CDOM*; and (iv) the water solvent for 1 O 2 [7]. The main mentioned formation and scavenging processes are summarized by the reactions below [3-7]: Molecules 2020, 25, 9 3 of 34 to validate this approach by comparing the predicted kinetics with known field data of pollutant phototransformation. Validation has been obtained in the cases of carbamazepine [18], ibuprofen [19], diclofenac and naproxen [20], atrazine [2...

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“…In the past decades, photocatalytic degradation has been proven to be a facile and efficient technology for degrading organic pollutants, including ionic liquids. − In this method, photoenergy is utilized to excite semiconductor catalysts to generate holes and the primary oxidizing species of ·OH. Then, the free radicals are able to unselectively attack and even mineralize the organic substances.…”

Section: Introductionmentioning

confidence: 99%

Plasmon-Enhanced Photodegradation of Ionic Liquids with Ag Nanocubes/ZnO Microsphere Composites

Huang

Zhang

et al. 2018

Ind. Eng. Chem. Res.

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Ionic liquids (ILs) have been a hot topic in the past decades because of their unique properties and promising applications in various areas. However, the toxicity of ILs and their possible risk to the environment and aquatic organisms have also been confirmed. Therefore, it is imperative to seek an efficient way to remove or degrade ILs in the polluted aqueous system. In this work, Ag nanocubes/ZnO microspheres composites have been designed, prepared, and used for the photocatalytic degradation of eight commonly used imidazolium-based ILs in aqueous solution. It is found that ZnO semiconductor photocatalyst with an Ag content of 1.12 at. % can degrade 90% of all these ILs within 7 h. The structural characterization, photoluminescence analysis, and discrete dipole approximation calculations showed that the loading of Ag nanocubes onto ZnO microspheres significantly improves the performance of ZnO for the IL degradation through hot electron transfer and electrical field enhancement. In addition, the formed intermediates in the degradation process of [C4 mim]Cl have been detected by gas chromatography–mass spectroscopy. A possible degradation mechanism is proposed and compared with those previously reported in the chemical degradation.

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Photoinduced transformation of pyridinium-based ionic liquids, and implications for their photochemical behavior in surface waters

Cited by 28 publications

References 53 publications

Photochemistry of Surface Fresh Waters in the Framework of Climate Change

Photochemistry of Surface Fresh Waters in the Framework of Climate Change

A Critical View of the Application of the APEX Software (Aqueous Photochemistry of Environmentally-Occurring Xenobiotics) to Predict Photoreaction Kinetics in Surface Freshwaters

Plasmon-Enhanced Photodegradation of Ionic Liquids with Ag Nanocubes/ZnO Microsphere Composites

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