Solar irradiation-induced photochemical processing of dissolved organic matter in reclaimed water

Abstract. An organic aerosol particle has a lifetime of approximately 1 week in the atmosphere during which it will be exposed to sunlight. However, the effect of photochemistry on the propensity of organic matter to participate in the initial cloud-forming steps is difficult to predict. In this study, we quantify on a molecular scale the effect of photochemical exposure of naturally occurring dissolved organic matter (DOM) and of a fulvic acid standard on its cloud condensation nuclei (CCN) and ice nucleation (IN) activity. We find that photochemical processing, equivalent to 4.6 d in the atmosphere, of DOM increases its ability to form cloud droplets by up to a factor of 2.5 but decreases its ability to form ice crystals at a loss rate of −0.04 ∘CT50 h−1 of sunlight at ground level. In other words, the ice nucleation activity of photooxidized DOM can require up to 4 ∘C colder temperatures for 50 % of the droplets to activate as ice crystals under immersion freezing conditions. This temperature change could impact the ratio of ice to water droplets within a mixed-phase cloud by delaying the onset of glaciation and by increasing the supercooled liquid fraction of the cloud, thereby modifying the radiative properties and the lifetime of the cloud. Concurrently, a photomineralization mechanism was quantified by monitoring the loss of organic carbon and the simultaneous production of organic acids, such as formic, acetic, oxalic and pyruvic acids, CO and CO2. This mechanism explains and predicts the observed increase in CCN and decrease in IN efficiencies. Indeed, we show that photochemical processing can be a dominant atmospheric ageing process, impacting CCN and IN efficiencies and concentrations. Photomineralization can thus alter the aerosol–cloud radiative effects of organic matter by modifying the supercooled-liquid-water-to-ice-crystal ratio in mixed-phase clouds with implications for cloud lifetime, precipitation patterns and the hydrological cycle.Highlights. During atmospheric transport, dissolved organic matter (DOM) within aqueous aerosols undergoes photochemistry. We find that photochemical processing of DOM increases its ability to form cloud droplets but decreases its ability to form ice crystals over a simulated 4.6 d in the atmosphere. A photomineralization mechanism involving the loss of organic carbon and the production of organic acids, CO and CO2 explains the observed changes and affects the liquid-water-to-ice ratio in clouds.

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Removal of fluorescence and ultraviolet absorbance of dissolved organic matter in reclaimed water by solar light

Journal of Environmental Sciences ◽

10.1016/j.jes.2015.08.021 ◽

2016 ◽

Vol 43 ◽

pp. 118-127 ◽

Cited By ~ 15

Author(s):

Qianyuan Wu ◽

Chao Li ◽

Wenlong Wang ◽

Tao He ◽

Hongying Hu ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Reclaimed Water ◽

Solar Light ◽

Ultraviolet Absorbance

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Resolution of photo chemically induced changes of dissolved organic matter as function of cumulated radiation in a sample of a humic-rich and forested stream

10.5194/egusphere-egu2020-5145 ◽

2020 ◽

Author(s):

Peter Herzsprung ◽

Christin Wilske ◽

Wolf von Tümpling ◽

Norbert Kamjunke ◽

Oliver J. Lechtenfeld

Keyword(s):

Drinking Water ◽

Organic Matter ◽

Dissolved Organic Matter ◽

Fluorescence Intensity ◽

Solar Irradiation ◽

Large Reservoir ◽

Photo Degradation ◽

Peak Intensity ◽

Ft Icr Ms ◽

Ft Icr

Photochemical processing is a major transformation pathway for allochthonous and autochthonous dissolved organic matter (DOM). DOM consists of thousands or even millions of different molecules and the isomer-resolved identification molecular structures is still far from any analytical realization. The highest analytical resolution of DOM can be achieved on a molecular mass basis via Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). With this technique, the molecular elemental compositions of thousands of DOM components can be assessed, given that they are extractable from water (via e.g. solid phase extraction, SPE-DOM) and ionizable (e.g. via electrospray ionization).Increasing levels of DOC in drinking water reservoirs pose serious challenges for drinking water processing. Photochemical processes potentially influence the DOM quality in the reservoir water. The photo degradation and / or the photo production of DOM components in surface freshwater as function of cumulated radiation was rarely investigated. In order to fill this gap we performed an irradiation experiment with water from a shaded forest stream flowing into a large reservoir (Muldenberg, Germany). DOC concentration, UV absorption, excitation-emission-matrices (EEMs) including calculated PARAFAC components and fluorescence indices, and FT-ICR MS derived molecular formulas of SPE-DOM were recorded at 13 different time points. The cumulated radiation was recorded during six days of solar irradiation (sunny days in August at 50.401847 deg. latitude and 12.380528 deg. longitude). Changes in relative peak intensity of DOM components as function of cumulated radiation were evaluated both by Spearman`s rank correlation and linear regression.We found components with different types of photo reaction behavior. Relative aliphatic components like C9H12O5 were identified as photo products showing a monotonous mass peak intensity increase with irradiation time. Highly unsaturated and oxygen-rich components like C15H6O8 showed a more or less monotonous intensity decrease indicating photo degradation. Many similar components were positively correlated to the humic-like fluorescence intensity and the humification index (HIX). The strong degradation of these components can explain the high loss of fluorescence intensity and the drop of the HIX in our experiment. As a result of the high temporal resolution in our experiment (i.e. intensity change as function of cumulated irradiation) we found another type of photo reaction. Components like C15H16O8 showed first increasing and then decreasing intensity indicating the formation of intermediate products.In general, the river DOM from the forested catchment area showed high potential for photochemical transformations which probably occur in the sunlight exposed predam of the drinking water reservoir.

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Photodegradation of dissolved organic matter in ice under solar irradiation

Chemosphere ◽

10.1016/j.chemosphere.2015.09.059 ◽

2016 ◽

Vol 144 ◽

pp. 816-826 ◽

Cited By ~ 12

Author(s):

Shuang Xue ◽

Chao Wang ◽

Zhaohong Zhang ◽

Youtao Song ◽

Qiang Liu

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Solar Irradiation

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Molecular characterization of dissolved organic matter in various urban water resources using Orbitrap Fourier transform mass spectrometry

Water Science & Technology Water Supply ◽

10.2166/ws.2014.006 ◽

2014 ◽

Vol 14 (4) ◽

pp. 547-553 ◽

Cited By ~ 15

Author(s):

M. Urai ◽

I. Kasuga ◽

F. Kurisu ◽

H. Furumai

Keyword(s):

Mass Spectrometry ◽

Organic Matter ◽

Fourier Transform ◽

Water Resources ◽

Dissolved Organic Matter ◽

River Water ◽

Fourier Transform Mass Spectrometry ◽

Reclaimed Water ◽

Urban Water

Molecular-level characterization of dissolved organic matter (DOM) in different urban water resources (river water, groundwater, reclaimed water, and rainwater) was performed by Orbitrap Fourier transform mass spectrometry (FT-MS). The mass spectra, which were fingerprints of DOM composition, were clearly different among samples. Based on accurate molecular mass determination, about 300 molecular formulae were identified. Most of the DOM molecules were composed of carbon, hydrogen and oxygen. Molecular formulae in river water consisted of CHO mostly and much less N- and S-containing compounds than other water samples. The percentage of CHO molecules was the highest for reclaimed water. The reclaimed water sample was characterized by a few peaks with strong intensities, which were presumed to be linear alkylbenzene sulfonates, their co-products and their biodegradation products based on their molecular formulae. Some of these compounds were also detected from river water, probably indicating the impact of wastewater treatment plants located upstream of the sampling point. Orbitrap FT-MS analysis is a powerful tool to discriminate DOM composition of urban water resources.

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Degradation of UV filters 2-ethylhexyl-4-methoxycinnamate and 4-tert-butyl-4'-methoxydibenzoylmethane in chlorinated water

Environmental Chemistry ◽

10.1071/en13012 ◽

2013 ◽

Vol 10 (2) ◽

pp. 127 ◽

Cited By ~ 27

Author(s):

A. Joel M. Santos ◽

Diana M. A. Crista ◽

Margarida S. Miranda ◽

Isabel F. Almeida ◽

José P. Sousa e Silva ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Rate Constant ◽

Half Life ◽

Chlorine Concentration ◽

Solar Irradiation ◽

Uv Filters ◽

Tert Butyl ◽

The Stability ◽

By Products

Environmental context The increasing use of sun-creams containing UV-filtering chemicals has led to increased inputs of these compounds to the aquatic environment. Chlorinated waters can convert these chemicals into chlorinated products whose toxic effects are of primary concern. To better understand the environmental fate of sun-cream chemicals, we studied the stability of two UV-filtering compounds under varying conditions of pH, chlorine concentration, temperature, dissolved organic matter and solar irradiation. Abstract The stability of the UV filters 2-ethylhexyl-4-methoxycinnamate (EHMC) and 4-tert-butyl-4′-methoxydibenzoylmethane (BDM) in chlorinated water was studied. High-performance liquid chromatography (HPLC)-UV-diode array detection (DAD) was used to follow the reaction kinetics of both UV filters and HPLC-tandem mass spectrometry (MS/MS) was used to tentatively identify the major transformation by-products. Under the experimental conditions used in this work both UV filters reacted with chlorine following pseudo-first order kinetics: rate constant k=0.0095±0.0007min–1 and half-life t1/2=73±4min for EHMC and rate constant k=0.006±0.001min–1 and half-life t1/2=119±14min for BDM (mean±standard deviation). The chemical transformation of the UV filters in chlorinated water led to the formation of chlorinated by-products that were tentatively identified as mono- and dichloro-substituted compounds that resulted from substitution of the hydrogen atoms in the benzene rings by one or two chlorine atoms. Experimental Box–Behnken designs were used to assess the effect of experimental factors: pH, temperature, chlorine concentration, dissolved organic matter and artificial sunlight irradiation on the transformation of the UV filters.

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Transformation of Dissolved Organic Matter in a Novel Groundwater Recharge System with Reclaimed Water

Water Environment Research ◽

10.2175/106143011x12928814445014 ◽

2011 ◽

Vol 83 (12) ◽

pp. 2140-2147 ◽

Cited By ~ 2

Author(s):

Wu Linlin ◽

Zhao Xuan ◽

Zhang Meng

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Groundwater Recharge ◽

Reclaimed Water

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Emission of (chlorinated) reclaimed water into a Mediterranean River and its related effects to the dissolved organic matter fingerprint

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.143881 ◽

2021 ◽

Vol 760 ◽

pp. 143881

Author(s):

Josep Sanchís ◽

Mira Petrović ◽

Maria José Farré

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Reclaimed Water ◽

Mediterranean River

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Photomineralization mechanism changes the ability of dissolved organic matter to activate cloud droplets and to nucleate ice crystals

10.5194/acp-2019-427 ◽

2019 ◽

Author(s):

Nadine Borduas-Dedekind ◽

Rachele Ossola ◽

Robert O. David ◽

Lin S. Boynton ◽

Vera Weichlinger ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Hydrological Cycle ◽

Supercooled Liquid ◽

Mixed Phase ◽

Ice Crystals ◽

Radiative Properties ◽

Cloud Droplets ◽

Photochemical Processing ◽

Mixed Phase Clouds

Abstract. An organic aerosol particle has a lifetime of approximately one week in the atmosphere during which it will be exposed to sunlight. Yet, the effect of photochemistry on the propensity of organic matter to participate in the initial cloud-forming steps is difficult to predict. In this study, we quantify on a molecular scale the effect of photochemical exposure of naturally occurring dissolved organic matter (DOM) and of a fulvic acid standard on its ability to form mixed-phase clouds, by acting as cloud condensation nuclei (CCN) and by acting as ice nucleating particles (INPs). We find that photochemical processing, equivalent to 4.6 days in the atmosphere, of DOM increases its ability to form cloud droplets by up to a factor of 2.5 but decreases its ability to form ice crystals at a loss rate of −0.04°CT50 h−1 of sunlight at ground level. In other words, the ice nucleation activity of photooxidized DOM can require up to 4 degrees colder temperatures for 50 % of the droplets to activate as ice crystals under immersion freezing conditions. This temperature change could impact the ratio of ice to water droplets within a mixed phase cloud by delaying the onset of glaciation and by increasing the supercooled liquid fraction of the cloud, thereby modifying the radiative properties and the lifetime of the cloud. Concurrently, a photomineralization mechanism was quantified by monitoring the loss of organic carbon and the simultaneous production of organic acids, such as formic, acetic, oxalic and pyruvic acids, CO and CO2. This mechanism explains and predicts the observed increase in CCN and decrease in INP efficiencies. Indeed, we show that photochemical processing can be a dominant atmospheric aging process, impacting CCN and INP efficiencies and concentrations. Photomineralization can thus alter the aerosol-cloud radiative effects of organic matter by modifying the supercooled liquid water-to-ice crystal ratio in mixed-phase clouds with implications for cloud lifetime, precipitation patterns and the hydrological cycle.

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