研究报告
郭晗,关雪峰,薛爽,张朝星,张朝红,于英潭,刘强.光照条件下冰相中激发三线态溶解性有机物的生成及其对三甲基苯酚的光敏化降解作用[J].环境科学学报,2022,42(8):186-193
光照条件下冰相中激发三线态溶解性有机物的生成及其对三甲基苯酚的光敏化降解作用
- Formation of excited triplet dissolved organic matter in ice phase under light and the photosensitive degradation of trimethylphenol
- 基金项目：国家自然科学基金（No.41771503，41703110）
- 作者
- 单位
- 郭晗
- 辽宁大学环境学院，沈阳 110036
- 关雪峰
- 辽宁大学环境学院，沈阳 110036;沈阳有色金属研究院有限公司，沈阳 110021
- 薛爽
- 辽宁大学环境学院，沈阳 110036
- 张朝星
- 辽宁大学环境学院，沈阳 110036
- 张朝红
- 辽宁大学环境学院，沈阳 110036
- 于英潭
- 辽宁大学环境学院，沈阳 110036
- 刘强
- 辽宁大学环境学院，沈阳 110036
- 摘要：选用两种天然有机物Upper Mississippi River NOM（UMRNOM）和Suwannee River NOM（SRNOM）作为光敏化剂，以500 W高压汞灯模拟太阳光照，用2，4，6-三甲基苯酚（TMP）作为探针，进行光解实验.考察了TMP是否可以作为冰相中激发三线态溶解性有机物（3DOM*）的探针，以及溶解性有机碳（DOC）浓度、pH值和溶解氧含量对光反应生成3DOM*的影响.结果表明，TMP的直接光降解和单线态氧（1O2）、羟基自由基（?OH）对TMP检测3DOM*的影响可以忽略，TMP可以作为冰冻样品中3DOM*的探针.UMRNOM的荧光强度和光化学活性低于SRNOM，在光反应中3DOM*的生成量低.两种DOM的SUVA254、E2/E3和荧光指数均与pH没有相关性，产生的3DOM*也与pH不相关. 3DOM*生成量随着DOC 浓度的增加而增加，单位DOC的3DOM*生成量随着浓度的增加而减少.此外，充入氮气的样品中TMP的降解速率比空气饱和样品分别高13.15%和16.43%.
- Abstract：The feasibility of 2，4，6-trimethylphenol （TMP） as a probe for excited triplet dissolved organic matter （3DOM*） in ice phase was investigated and the effects of dissolved organic carbon （DOC） concentration， pH and dissolved oxygen on the production of 3DOM* in ice were examined by using a 500W high-pressure Xenon lamp to simulate solar irradiation. Upper Mississippi River NOM （UMRNOM） and Suwannee River NOM （SRNOM） were used as photosensitizers， and TMP was used as the probe. The results showed that the direct photodegradation of TMP and the effects of singlet oxygen （1O2） and hydroxyl radicals （?OH） on the detection of 3DOM* can be ignored， and TMP can be used as a probe for 3DOM* in frozen samples. The fluorescence intensity and photochemical activity of UMRNOM were lower than that of SRNOM， and as a result， the production of 3DOM* was also lower. None of SUVA254， E2/E3 and fluorescence index of UMRNOM and SRNOM has any correlation with pH. The generation of 3DOM*was also pH-independent. 3DOM* production increased with the increase of DOC concentration. However， 3DOM* production per DOC decreased with the increase of DOC concentration. In addition，the degradation rates of TMP observed from UMRNOM and SRNOM samples filled with nitrogen were 13.15% and 16.43% higher than those from the corresponding air-saturated samples， respectively.
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