水冰相中溶解性有机物对单线态氧的淬灭  

Quenching of singlet oxygen by dissolved organic matter in liquid and ice phase

作　　者：刘琪 薛爽[1] 姜彩虹 张朝红[1] LIU Qi;XUE Shuang;JIANG Caihong;ZHANG Zhaohong(School of Environment,Liaoning University,Shenyang 110000)

机构地区：[1]辽宁大学环境学院,沈阳110000

出　　处：《环境科学学报》2023年第9期110-120,共11页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.41771503)。

摘　　要：利用500 W汞灯作为光源模拟太阳光,以苏万尼河富里酸(Suwannee river fulvic acid,SRFA)和风化褐煤腐殖酸(Leonarditehumic acid,LHA)两种溶解性有机物(Dissolved organic matter,DOM)为研究对象,进行糠醇(FFA)的光解实验.考察了水冰相中不同pH条件下DOM对单线态氧(Singlet oxygen,^(1)O_(2))的淬灭,以及不同浓度的DOM对^(1)O_(2)的淬灭.结果表明,pH能改变DOM的紫外吸收和荧光光谱学特征参数,并且冻融处理会影响DOM的光谱学特性.水冰相中DOM浓度的增加均导致DOM对1O2的淬灭常数(kq,DOM)的降低.水相中两种DOM都是在中性条件(pH=7)下对^(1)O_(2)的淬灭效应弱于酸性条件(pH=5)和碱性条件(pH=9).在水冰相中不同浓度的DOM所产生的^(1)O_(2)的稳态浓度([^(1)O_(2)]_(ss),DOM)与DOM在254 nm处的吸光度(a_(254))、DOM在300 nm处的吸光度(a_(300))及荧光强度呈正相关(p<0.05).水相中不同浓度的DOM的kq,DOM与其[^(1)O_(2)]_(ss),DOM、a_(254)、a_(300)及荧光强度呈负相关(p<0.05).A 500W mercury lamp was used as the light source to simulate the sunlight,and Suwannee river fulvic acid(SRFA)and Leonarditehumic acid(LHA)were used as the research objects for photolysis experiments of furfuryl alcohol(FFA).The quenching of singlet oxygen(^(1)O_(2))by DOM with different concentrations as well as at different pH conditions in water and ice was investigated.The results showed that pH can change the characteristic parameters of UV absorption and fluorescence spectroscopy of DOM,and freeze-thaw treatment can affect the spectral characteristics of DOM.The quenching constant(k_(q),DOM)of DOM to ^(1)O_(2) decreased with the increase of DOM concentration in both water and ice.In water,the quenching effect of the two DOM on ^(1)O_(2) under neutral conditions(pH=7)was weaker than that under acidic conditions(pH=5)and alkaline conditions(pH=9).In both water and ice,steady-state concentration of ^(1)O_(2)([^(1)O_(2)]_(ss),DOM)of DOM with different concentrations was negatively correlated with absorbance of DOM at 254 nm(a254),absorbance of DOM at 300 nm(a_(300))and fluorescence intensity(p<0.05).In water,kq,DOM for DOM with different concentrations was negatively correlated with[^(1)O_(2)]_(ss),DOM,a_(254),a_(300) and fluorescence intensity(p<0.05).

关 键 词：溶解性有机质 水冰相 单线态氧 淬灭 浓度 PH 

分 类 号：X131.2[环境科学与工程—环境科学]