垃圾填埋渗滤液溶解性有机物组分的光谱学特性研究

选取3个不同填埋年限的渗滤液样品,以Leenheer的分组方法为基础,采用XAD-8树脂将渗滤液中的溶解性有机物(DOM)按极性和电荷特性分为结构较为均一的不同组分,用荧光光谱和紫外光谱对其中3个组分进行分析。荧光光谱分析表明,填埋初期,疏水酸性组分(HOA)、疏水中性组分(HON)和亲水性组分(HIM)均以类蛋白物质为主,随着填埋年限增加,其分子复杂化程度增强;其中HOA组分分子量最大、复杂程度最高,同时芳烃化合物的含量也最高,HON居中,HIM组分最小。紫外光谱分析表明,HOA和HON组分芳香环上的取代基均以羰基、羧基、羟基为主;而HIM组分则以脂肪链为主,同时芳香烃化合物含量较低。研究结果表明,随着填埋年限的增加,三种组分的复杂化程度均呈上升趋势。

Study on Spectral Characteristic of Dissolved Organic Matter Fractions Extracted from Municipal Solid Waste Landfill Leachate

In the present study,the samples of landfill leachate of 0,5,10-year-old were respectively taken from landfill plant.Based on a modified Leenheer fractionation scheme,dissolved organic matter(DOM) extracted from landfill leachate of three different ages was fractioned according to their polarities and charge characteristics by using XAD-8 resin,and the fractions of hydrophobic acid (HOA),neutral(HON) and hydrophilic matter(HIM) were obtained,Then the fluorescence and UV spectra of DOM fractions were determined.The fluorescence synchronous scan spectra of DOM fractions exhibited a primary peak at 280 nm for 0-year-old,while the primary peak exhibited at 340nm for 5 and 10 yearold,suggesting that DOM fractions contained mainly protein-like matter at initial stage of landfill,and with the increase in landfill ages,aromatic structures of DOM fractions in leachate were enriched.Among the DOM fractions of HOA,HON and HIM at different ages of landfill leachate,the fluorescence and UV spectra all indicated that the molecular weight,content of aromatic compounds and degree of condensation were all in the order of HOA>HON>HIM.The ratio of UV absorbance at 253 nm to that at 203 nm(A253/A203) showed,that the substituent on the aromatic ring of HOA and HON fractions consisted mainly of carbonyl,carboxyl and hydroxyl;while that of HIM consisted of aliphatic chains,and the content of aromatic compounds was lower than that of HOA and HON;which implied that the HIM displayed a lower molecular weight and simpler structure compared to HOA and HON.Altogether,the results obtained from fluorescence and UV spectra indicate that the degree of aromatization increased in DOM fractions of leachate with the landfill ages,in the following order: HOA>HON>HIM.