DOM结构特征及其对17β-雌二醇光降解的影响  

Structural characteristics of DOM and its effects on the photodegradation of 17β-estradiol

作　　者：任东[1] 杨小霞[1] 马晓冬[1] 顾丽鹏 黄斌[1] 潘学军[1] 

机构地区：[1]昆明理工大学环境科学与工程学院,云南昆明650500

出　　处：《中国环境科学》2015年第5期1375-1383,共9页China Environmental Science

基　　金：国家自然科学基金(41401558);中国博士后科学基金(2014T70887;2013M531987);云南省应用基础研究计划项目(2012FB124);云南省教育厅科学研究基金项目(2014J022);中国科学院环境化学与生态毒理学国家重点实验室开放基金(KF2013-04)

摘　　要：参照国际腐殖酸协会(IHSS)推荐的方法从滇池底泥提取出胡敏酸(HA)和富里酸(FA),以Sigma Aldrich胡敏酸(SAHA)为参照,利用元素分析、13C核磁共振和紫外-可见光谱对HA和FA的来源和结构进行了表征,并探讨了3种溶解性有机质(DOM)对17β-雌二醇(E2)光降解的影响.结果表明:HA、FA和SAHA具有相似的元素组成,3种腐殖酸的(N+O)/C值分别为0.50、0.82和0.55,与核磁共振13C谱分析的极性指数(0.32、0.42和0.33)一致.HA和FA来自于内源,具有较高的N含量和较多的缔合芳香结构,而SAHA是外源性有机质,具有更高的芳香度.低浓度的3种腐殖酸均能促进E2发生服从准一级动力学规律的光化学降解过程.E2在纯水中光降解速率为0.0071h-1,而在5mg C/L的HA、FA和SAHA作用下,E2光降解速率分别为0.0597、0.1178和0.2048h-1.3种腐殖酸促进E2光降解能力的差异主要是由含氧能团和芳香结构含量差异所致.活性氧分子探针鉴定显示HO?是腐殖酸体系受光照后产生的一种重要活性氧,其氧化降解E2的量占到了E2降解总量的70%左右.与低浓度腐殖酸相比,高浓度的3种腐殖酸均会对E2光降解产生抑制作用.Elemental analysis, UV-vis spectroscopy and 13C nuclear magnetic resonance were used to characterize the humic acid （HA） and fulvic acid （FA）, which were extracted from the sediments, collected from Dianchi Lake, by the methods recommended by International Humic Substance Society （IHSS）. Optical and structural characteristics of the two dissolved organic matter （DOM） were compared with that of the humic acid purchased from Sigma Aldrich （SAHA）, and their effects on the 17β-estradiol （E2） photodegradation were also studied. It was found that HA and FA has similar element composition with SAHA, and the value of （N＋O）/C was 0.50, 0.82 and 0.55 for HA, FA and SAHA, respectively. The polarity index analyzed by 13C NMR was 0.32 for HA, 0.42 for FA and 0.33 for SAHA, which was consistent with the result of elemental analysis. HA and FA are endogenous DOM with higher nitrogen content and associative aromatic cycles than SAHA, whereas the SAHA is an extrinsic DOM with higher aromaticity. HA, FA and SAHA all can promote the photodegradation of E2 when compared with that in ultrapure water （k = 0.0071h^-1）. The rate constant is 0.0597, 0.1178 and 0.2048h-I when mediated by 5mgC/L HA, FA and SAHA, respectively. The HO＇, contributing approximate 70% to the photodegradation of E2, is an important reactive oxygen species （ROS） produced by the irradiated humic substances. The promoting ability of the three humic substances is controlled by the oxygen-containing functions and aromatic structures. These humic substances, at lower concentration, can significantly promote the photodegradation of E2, whereas the higher concentration DOM could inhibit the photodegradation of E2 by quenching the ROS and filtering the incident light.

关 键 词：胡敏酸 富里酸 结构特征 17Β-雌二醇 活性氧 光降解 

分 类 号：X132[环境科学与工程—环境科学]