Photodegradation of hydroxyfluorenes in ice and water: A comparison of kinetics, effects of water constituents, and phototransformation by-products  

作　　者：Linke Ge Shengkai Cao Crispin Halsall Junfeng Niu Dongxiao Bai Guangkai He Peng Zhang Hongrui Ma 

机构地区：[1]School of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China [2]Lancaster Environment Centre,Lancaster University,Lancaster LA14YQ,UK [3]State Environmental Protection Key Laboratory of Coastal Ecosystem,National Marine Environmental Monitoring Center,Dalian 116023,China

出　　处：《Journal of Environmental Sciences》2023年第2期139-145,共7页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos. 21976045, 22076112);the CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation (No. 2020KFJJ03);the State Environmental Protection Key Laboratory of Coastal Ecosystem (No. 202102);the China Scholarship Council (CSC) Scholarship (Nos. 201704180014, 201704180009);the Chinese Arctic and Antarctic Administration

摘　　要：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^(−),NO_(3)^(−),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.

关 键 词：Ice photochemistry Hydroxyfluorene PHOTODEGRADATION KINETICS Water constituents INTERMEDIATES 

分 类 号：X505[环境科学与工程—环境工程]