光和生物改性溶解性有机质介导17α-乙炔基雌二醇厌氧降解

Anaerobic degradation of 17α-ethynylestradiol mediated by photo-and biomodified dissolved organic matters

自然水体溶解性有机质(DOM)在光照和微生物存在的条件下理化性质会发生改变,从而影响其对类固醇类雌激素降解的介导作用.本研究通过对从洱海沉积物中提取的两种典型DOM物质—胡敏酸(HA)和富里酸(FA)分别经过72 h的微生物改性和48 h的光改性,分别比较厌氧条件下光改性前后DOM介导微生物降解17α-乙炔基雌二醇(EE2)的能力变化,以及微生物改性前后DOM介导光降解EE2的能力变化.同时,通过紫外可见吸收光谱、三维荧光光谱和电子供给能力对改性前后的DOM进行分析.结果表明:经过微生物改性后,HA和FA的荧光强度和腐殖化程度都有所提高,但紫外吸光强度和芳香性降低,并且与污染物的结合能力提高,使得光照条件下其介导的EE2更容易发生降解反应.微生物改性后HA介导下的EE2光降解效果要明显好于FA的介导效果.经过光改性后,HA和FA紫外吸光强度和芳香性升高,荧光强度和电子供给能力降低.光改性后HA介导下的EE2微生物降解效果要明显好于FA的介导效果.可见自然水体中微生物改性DOM介导的EE2降解效果相比光改性DOM的介导更加明显.

The changes of dissolved organic matters（ DOM） physicochemical property in the presence of light and microorganism would have an obvious influence on steroid estrogen degradation. Humic acid（ HA） and fulvic acid（ FA） were extracted from sediments of Erhai Lake and were subjected to biomodification for 72 hours and photo-modification for 48 hours,respectively. The degradation of 17α-ethynylestradiol（ EE2） under anaerobic condition in the presence of DOM after bio-modification and photo-modification were explored,respectively. The characterizations of DOM before and after modification were analyzed by UV-vis spectroscopy,fluorescence spectrophotometer and electron donating capacity. The results show that,fluorescence intensity and humification of HA and FA increased after bio-modification,however,UV absorbance and the aromaticity decreased. Due to the improvement of binding ability between HA and FA and pollutants,EE2 photodegradation was promoted. The photodegradation of EE2 mediated by bio-modified HA was better than that of FA. In addition,UV absorbance and the aromaticity of HA and FA after photo-modification increased,while,fluorescence intensity and electron donating capacity decreased. The biodegradation of EE2 mediated by photo-modified HA was better than FA. It can be seen that EE2 photodegradation mediated by bio-modified DOM is more obvious than the biodegradation mediated by photo-modified DOM in aquatic environment.