Abstract：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-1 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.
任东, 杨小霞, 马晓冬, 顾丽鹏, 黄斌, 潘学军. DOM结构特征及其对17β-雌二醇光降解的影响[J]. 中国环境科学, 2015, 35(5): 1375-1383.
REN Dong, YANG Xiao-Xia, MA Xiao-Dong, GU Li-Peng, HUANG Bin, PAN Xue-Jun. Structural characteristics of DOM and its effects on the photodegradation of 17β-estradiol. CHINA ENVIRONMENTAL SCIENCECE, 2015, 35(5): 1375-1383.
