Rights statement: This is the author’s version of a work that was accepted for publication in Journal of Environmental Sciences. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Environmental Sciences, 124, 2022 DOI: 10.1016/j.jes.2021.11.002
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Photodegradation of hydroxyfluorenes in ice and water
T2 - A comparison of kinetics, effects of water constituents, and phototransformation by-products
AU - Ge, L.
AU - Cao, S.
AU - Halsall, C.
AU - Niu, J.
AU - Bai, D.
AU - He, G.
AU - Zhang, P.
AU - Ma, H.
N1 - This is the author’s version of a work that was accepted for publication in Journal of Environmental Sciences. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Environmental Sciences, 124, 2022 DOI: 10.1016/j.jes.2021.11.002
PY - 2023/2/28
Y1 - 2023/2/28
N2 - The photochemical behavior of organic pollutants in ice is poorly studied in comparison to aqueous photochemistry. Here we report a detailed comparison of ice and aqueous photodegradation of two representative OH-PAHs, 2-hydroxyfluorene (2-OHFL) and 9-hydroxyfluorene (9-OHFL), which are newly recognized contaminants in the wider environment including colder regions. Interestingly, their photodegradation kinetics were clearly influenced by whether they reside in ice or water. Under the same simulated solar irradiation (λ > 290 nm), OHFLs photodegraded faster in ice than in equivalent aqueous solutions and this was attributed to the specific concentration effect caused by freezing. Furthermore, the presence of dissolved constituents in ice also influenced photodegradation with 2-OHFL phototransforming the fastest in ‘seawater’ ice (k = (11.4 ± 1.0) × 10−2 min−1) followed by ‘pure-water’ ice ((8.7 ± 0.4) × 10−2 min−1) and ‘freshwater’ ice ((8.0 ± 0.7) × 10−2 min−1). The presence of dissolved constituents (specifically Cl−, NO3−, Fe(III) and humic acid) influences the phototransformation kinetics, either enhancing or suppressing phototransformation, but this is based on the quantity of the constituent present in the matrixes, the specific OHFL isomer and the matrix type (e.g., ice or aqueous solution). Careful derivation of key photointermediates was undertaken in both ice and water samples using tandem mass spectrometry. Ice phototransformation exhibited fewer by-products and ‘simpler’ pathways giving rise to a range of hydroxylated fluorenes and hydroxylated fluorenones in ice. These results are of importance when considering the fate of PAHs and OH-PAHs in cold regions and their persistence in sunlit ice.
AB - The photochemical behavior of organic pollutants in ice is poorly studied in comparison to aqueous photochemistry. Here we report a detailed comparison of ice and aqueous photodegradation of two representative OH-PAHs, 2-hydroxyfluorene (2-OHFL) and 9-hydroxyfluorene (9-OHFL), which are newly recognized contaminants in the wider environment including colder regions. Interestingly, their photodegradation kinetics were clearly influenced by whether they reside in ice or water. Under the same simulated solar irradiation (λ > 290 nm), OHFLs photodegraded faster in ice than in equivalent aqueous solutions and this was attributed to the specific concentration effect caused by freezing. Furthermore, the presence of dissolved constituents in ice also influenced photodegradation with 2-OHFL phototransforming the fastest in ‘seawater’ ice (k = (11.4 ± 1.0) × 10−2 min−1) followed by ‘pure-water’ ice ((8.7 ± 0.4) × 10−2 min−1) and ‘freshwater’ ice ((8.0 ± 0.7) × 10−2 min−1). The presence of dissolved constituents (specifically Cl−, NO3−, Fe(III) and humic acid) influences the phototransformation kinetics, either enhancing or suppressing phototransformation, but this is based on the quantity of the constituent present in the matrixes, the specific OHFL isomer and the matrix type (e.g., ice or aqueous solution). Careful derivation of key photointermediates was undertaken in both ice and water samples using tandem mass spectrometry. Ice phototransformation exhibited fewer by-products and ‘simpler’ pathways giving rise to a range of hydroxylated fluorenes and hydroxylated fluorenones in ice. These results are of importance when considering the fate of PAHs and OH-PAHs in cold regions and their persistence in sunlit ice.
KW - Hydroxyfluorene
KW - Ice photochemistry
KW - Intermediates
KW - Kinetics
KW - Photodegradation
KW - Water constituents
KW - Hydroxylation
KW - Iron compounds
KW - Ketones
KW - Mass spectrometry
KW - Organic pollutants
KW - Polycyclic aromatic hydrocarbons
KW - Cold regions
KW - Effect of water
KW - Intermediate
KW - Kinetic effect
KW - OH -
KW - Photo degradation
KW - Phototransformations
KW - Ice
U2 - 10.1016/j.jes.2021.11.002
DO - 10.1016/j.jes.2021.11.002
M3 - Journal article
VL - 124
SP - 139
EP - 145
JO - Journal of Environmental Sciences (China)
JF - Journal of Environmental Sciences (China)
ER -