氧化还原过程对好氧微生物产物光敏性的影响

Effect on photosensitization activities of soluble microbial products by redox processes

从好氧活性污泥微生物和纯种大肠杆菌中提取溶解性微生物产物(SMP),考察光化学和电化学氧化还原过程对SMP官能团,组分和光化学活性的影响机制.结果显示,活性污泥微生物SMP(Ae)与大肠杆菌SMP(E)的SUVA_(254)和E2/E3分别为4.03与0.79和1.60与3.04,表明SMP(Ae)比SMP(E)芳香性和分子量更高,光照和电化学改性过程明显降低了蛋白类组分的荧光响应,进行改变了SMP的芳香性和腐殖化程度.两种改性过程可以增强SMP在光照条件下活性氧化物种(^(3)SMP^(*)、^(1)O_(2)和·OH)的浓度,其中[^(1)O_(2)]_(ss)由改性前的1.70mol/L提高到改性后的18.47mol/L,[·OH]_(ss)由改性前的3.57mol/L提升到438.25mol/L.17α-乙炔基雌二醇(EE2)的光降解效率在改性SMP的介导下最高提升了近5倍.本研究完善了污水处理厂出水中SMP的环境转化过程及其介导痕量有机污染物的自然光降解过程的科学认识.

In this study,the microorganisms in aerobic activated sludge(Ae)and pure microbial Escherichia coli(E)were used as the main sources of soluble microbial products(SMP)to investigate the influence of photochemical and electric potential redox processes on the changes in functional groups,components and photochemical activity of SMP.The results showed that the SUVA_(254) and E2/E3 of Ae and E were 4.03/0.79 and 1.60/3.04,respectively,indicating that Ae has the higher molecular weight and aromaticity than E.Besides,illumination and electrochemistry significantly decreased the fluorescence intensity and changed the aromaticity and humification degree of SMP.And these two processes can increase the concentration of active oxidation species(^(3)SMP^(*),^(1)O_(2)and·OH)of SMP under illumination conditions.The[^(1)O_(2)]_(ss)and[·OH]_(ss) increased from 1.70mol/L and 3.57mol/L to 18.47mol/L and 438.25mol/L,respectively.In addition,the photodegradation kinetic of 17α-ethinylestradiol(EE2)mediated by SMP improved by almost 5 folds after being modified.This study improved the scientific understanding of the natural transformation processes of SMP in wastewater treatment plant effluent and the natural photodegradation of trace pollutants mediated by SMP.