城市景观湖溶解性有机物特征及臭氧去除效能:以金海湖为例

Characteristics of DOM in Urban Landscape Water and Removal Effectiveness by Ozonation:Case of Jinhai Lake

分析城市景观湖溶解性有机物(DOM)的特征和可处理特性,有助于提高城市水环境质量,提出合理的有机污染控制策略。文章以金海湖水样为研究对象,通过紫外光谱、三维荧光光谱、液相色谱技术等分析方法探究其DOM特点,发现DOM具有强自生源、较低腐殖化程度、偏小有机物分子量的特征。随后对金海湖水样进行臭氧氧化处理,60 min后溶解性有机碳(DOC)、COD_(Mn)、UV_(254)、荧光强度(FI)、供电子官能团(EDM)的平均去除率分别为5.8%、13.1%、60.1%、70.0%、18.2%。结果表明,臭氧可以高效降解多种有机污染物,对金海湖DOM的紫外生色团、荧光团及大分子组分供电子官能团均有较强的去除能力,但对有机物的矿化能力和对小分子组分供电子官能团的去除能力较弱。臭氧通过将大分子有机物分解成小分子有机物,而非直接矿化,来实现对DOM的降解。

The analysis of dissolved organic matter(DOM)characteristics and treatable characteristics of urban landscape lake is helpful to improve the quality of urban water environment and put forward a reasonable organic pollution control strategy.Characteristics of the water samples of Jinhai Lake were analyzed by ultraviolet,visible spectroscopy,three-dimensional fluorescence spectroscopy,liquid chromatography and so on.It was found that the DOM exhibited characteristics of highly autochthony,low humification,and small molecular weight.After 60 min of ozonation,the removal rates of dissolved organic carbon(DOC),COD_(Mn),UV_(254),fluorescence index(FI),electron donating moieties(EDM)was 5.8%,13.1%,60.1%,70.0%,18.2%,respectively.These results indicated ozonation was an effective method for degrading a wide range of organic compounds in urban landscape water,particularly in the removal of ultraviolet chromophores,fluorophores,and electron donating moieties in high molecular weight fractions of DOM,while it was difficult to mineralize DOM and remove electron donating moieties in low molecular weight fractions.Thus,ozonation can degrade DOM by fragmenting higher molecular weight fractions leading to the formation of smaller molecular weight fractions,rather than by direct mineralization.