阴离子对城市污水二级出水DOM光谱特性影响

Effect of Anions on Spectral Properties of DOM from Secondary Sewage of Municipal Wastewater

利用三维荧光光谱法和紫外光谱法,研究阴离子对城市污水二级出水DOM光谱的影响,为环境中DOM分析提供数据基础。结果表明:投加SO_4^(2-)和Cl^-使二级出水DOM荧光峰强度小幅度增强或降低。投加NO_3^-浓度在0.005~0.1mol·L^(-1)时,出现代表可见光区类腐殖质的荧光峰。随投加NO_3^-浓度增大,荧光强度显著降低;代表类腐殖质荧光峰的激发波长和发射波长与紫外吸收峰右侧红移。NO_3^-投加浓度与HIX,UV_(254),UV_(253)/UV_(203),α_(300)和α_(250)/α_(365)呈较强的正相关性,决定系数分别为0.993,0.994,0.987,0.998和0.995;与BIX呈负相关性,R^2为0.949;对α_(350)和α_(355)影响不大。结果表明,投加SO_4^(2-)和Cl^-对二级出水DOM的荧光(除荧光强度外)和紫外特性影响较小。样品NO_3^-浓度不同时,用荧光参数和紫外参数衡量不同DOM来源和性质时将产生一定影响。

This study investigated how the anions had the effect on the spectral characteristics of dissolved organic matter（DOM）of secondary effluent from municipal wastewater treatment by using three-dimensional fluorescence spectroscopy and UV spectrophotometry in order to provide the data foundation for DOM＇s environmental behavior.The results showed that the addition of SO4^2- and Cl^- could increase or decrease the fluorescence intensity of DOM＇s fluorescence peaks.In addition,the fluorescence peak representing the visible humus-like was observed with the additional concentration of NO3^- with 0.005～0.1 mol·L^-1.Moreover,the fluorescence intensity of each fluorescence peak decreased obviously with the increase of NO3^- concentration,and the excitation and emission wavelengths of the fluorescence peaks representing the humus-like were red shifted with the right side of UV absorption peak.The added NO3^- concentration was positively correlated with HIX with the determination coefficient of 0.993.This was similar to that with UV（254）（0.994）,UV（253）/UV（203）（0.987）,α（300）（0.998）and α（250）/α（365）（0.995）.And it had the negative correlation with BIX as the determination coefficients was 0.949.However,it had no significant effect on α（350） and α（355）.In conclusion,the addition of SO4^2- andCl^- had little effect on the fluorescence and UV characteristics of secondary effluent DOM except fluorescence intensity.When the concentrations of NO3^- in the samples were different,it had a certain effect on analyzing the source and the properties of the different DOMs by using fluorescenct parameters and UV parameters.