Photochemical Production of Methyl Halides with Guaiacol as the Precursor

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外文摘要：Methyl halides are crucial trace greenhouse gases in the atmosphere,playing a significant role in global climate change and the atmospheric environment.This study investigated the photochemical production of methyl halides in an artificial seawater system using guaiacol as a precursor through laboratory simulation experiments.The influences of various environmental factors,including illumination time,radiation wavebands,illumination intensity,concentrations of guaiacol and halide ions(X-),Fe3+,salin-ity,dissolved oxygen(DO),and pH value on the photochemical production of methyl halides were examined.We demonstrated that increased illumination intensity and duration promote the photochemical production of methyl halides,with a notable enhancement under UV-B radiation.Guaiacol and halide ions were identified as key precursors,and their high concentrations facilitated the forma-tion of methyl halides.Additionally,different types of halide ions exhibited a competitive relationship in producing methyl halides.The study found that an increase in pH inhibited the photochemical formation of CH3I due to the reaction between OH-and·CH3.Dissolved oxygen was found to inhibit the photochemical formation of CH3I while promoting the formation of CH3C1.Conversely,an appropriate concentration of Fe3+enhanced the photochemical production of methyl halides.Field observations indicated a high photochemical production of methyl halides in the natural waters near Qingdao's coastal area,likely due to the high concentration of dissolved organic matter(DOM),which supports photochemical reactions.Furthermore,the photochemical production of methyl halides in natural seawater was significantly higher than in dark conditions,underscoring the importance of illumination in promoting these photochemical processes in seawater.

外文关键词：

methyl halidesphotochemical productiondissolved organic matterguaiacol

作者：

YANG Fan、ZHANG Yan、WU Guanyu、HE Zhen、YANG Guipeng

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作者单位：

Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology,Ministry of Education,Ocean University of China,Qingdao 266100,China

Frontiers Science Center for Deep Ocean Multispheres and Earth System,Key Laboratory of Marine Chemistry Theory and Technology,Ministry of Education,Ocean University of China,Qingdao 266100,China

Laboratory for Marine Ecology and Environmental Science,Qingdao Marine Science and Technology Center,Qingdao 266237,China

Institute of Marine Chemistry,Ocean University of China,Qingdao 266100,China

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基金：

Natural Science Foundation of Shandong Province,ChinaNational Natural Science Foundation of China

项目编号：

ZR2021MD03442276039

出版年：

2024

DOI：

10.1007/s11802-024-5962-9

中国海洋大学学报(自然科学英文版)