城市污水的三维荧光指纹特征

传统表征有机物含量的水质参量如化学需氧量(COD)和生化需氧量(BOD)等只能表示总量,无法展示有机物成分.荧光光谱可以作为一种新型的水质表示方法,它像指纹一样与水样一一对应,被称为水质荧光指纹.采用三维荧光光谱(EEM)技术研究了城市污水荧光指纹特征,结果表明城市污水具有4个典型荧光区,各区的荧光中心、强度以及1区荧光中心λex=280 nm,λem=340 nm与2区荧光中心λex=225 nm,λem=340 nm的荧光强度的比值可以作为城市污水的主要荧光指纹特征.荧光指纹包含了大量污染物信息,通过与城市污水中典型污染物质的荧光光谱的比对,初步确定了各荧光区可能的荧光信号来源.荧光指纹法可表示有机物类型和含量,可作为化学需氧量和生化需氧量等参量的有益补充.

Fluorescence Properties of Municipal Wastewater

The traditional parameters of water quality, shuch as chemical oxygen demand (COD) and biological oxygen demand (BOD), only present total organic substance concentration and are void for displaying pollutant compositions. Fluorescence spectrum, a novel method for water quality, is unique for each wastewater sample like ‘fingerprint’. Excitation-emission matrix (EEM) technology is used to study fluorescence properties of municipal wastewater. The results show that there are four typical fluorescence zones in EEMs of municipal wastewater. Locations and intensities of fluorescence peaks of each zone and the ratio of intensities at λex=280 nm,λem=340 nm (fluorescence center of the 1st zone) and λex=225 nm,λem=340 nm (fluorescence center of the 2nd zone) could exhibit main fluorescence features. Fluorescence fingerprint contains a great deal of pollutant information. By comparing EEMs of typical pollutants, the main fluorescence substances of wastewater are approximately identified. Fluorescence fingerprint method can present organic substance as well as their content and is well complementary to COD and BOD.