气候变化领域集成服务门户(CCPortal): Optical and chemical properties and oxidative potential of aqueous-phase products from OH and C-3*-initiated photooxiaation of eugenol

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DOI	10.5194/acp-22-7793-2022
	*Optical and chemical properties and oxidative potential of aqueous-phase products from OH and C-3-initiated photooxiaation of eugenol**
	Li, Xudon; Tao, Ye; Zhu, Longwei; Ma, Shuaishuai; Luo, Shipeng; Zhao, Zhuzi; Sun, Ning; Ge, Xinlei; Ye, Zhaolian
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	7793
结束页码	7814
卷号	22 期号:11 页码:22
英文摘要	Aqueous reactions may turn precursors into light-absorbing and toxic products, leading to air quality deterioration and adverse health effects. In this study, we comprehensively investigated eugenol photooxidation (a representative biomass-burning-emitted, highly substituted phenolic compound) in the bulk aqueous phase with direct photolysis, a hydroxyl radical (OH), and an organic triplet excited state (C-3). Results show that the degradation rates of eugenol followed the order of C-3 > OH > direct photolysis. During the C-3-initiated oxidation, different reactive oxygen species (ROS), including C-3, OH, O-1(2), and O-2(center dot-), can participate in the oxidation of eugenol, quenching experiments verified C-3* was the most important one, while, during OH-initiated oxidation, O-2(center dot-) was a more important ROS than OH for degrading eugenol. The rate constants under saturated O-2, air, and N-2 followed the order of k(O2) > k(Air) > k(N2) for both direct photolysis and OH-initiated oxidation but changed to k(Air) > k(N2) > k(O2) for C-3*-mediated oxidation. pH and dissolved oxygen (DO) levels both decreased during oxidation, indicating the formation of acids and the participation of DO in oxidation. Ultraviolet and visible (UV-vis) light absorption spectra of the reaction products showed a clear absorbance enhancement in the 300-400 nm range for all three sets of experiments, and new fluorescence at excitation/emission = 250/ (400-500) nm appeared, suggesting the formation of new chromophores and fluorophores (brown carbon species). These species were likely attributed to humic-like substances (HULIS), as shown by the increases in HULIS concentrations during oxidation. Large mass yields of products (140 %-197 %) after 23 h of illumination were obtained, and high oxidation degrees of these products were also observed. Correspondingly, a series of oxygenated compounds were identified, and a detailed reaction mechanism with functionalization as a dominant pathway was proposed. At last, the dithiothreitol (DTT) assay was applied to assess the oxidation potential of the reaction products, and the end products of all three sets of experiments showed higher DTT consumption rates than those of eugenol, indicating that more toxic species were produced upon aqueous oxidation. Overall, our results from using eugenol as a model compound, underscore the potential importance of the aqueous processing of biomass burning emissions in secondary organic aerosol (SOA) formation.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000811027100001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273046
作者单位	Jiangsu University of Technology; Nanjing University of Information Science & Technology
推荐引用方式 GB/T 7714	Li, Xudon,Tao, Ye,Zhu, Longwei,et al. Optical and chemical properties and oxidative potential of aqueous-phase products from OH and C-3*-initiated photooxiaation of eugenol[J],2022,22(11):22.
APA	Li, Xudon.,Tao, Ye.,Zhu, Longwei.,Ma, Shuaishuai.,Luo, Shipeng.,...&Ye, Zhaolian.(2022).Optical and chemical properties and oxidative potential of aqueous-phase products from OH and C-3*-initiated photooxiaation of eugenol.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(11),22.
MLA	Li, Xudon,et al."Optical and chemical properties and oxidative potential of aqueous-phase products from OH and C-3*-initiated photooxiaation of eugenol".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.11(2022):22.