In this study, humic acid (HA) was selected as a model compound of dissolved organic matter and used to study the effect of NaOCl on its structural and optical characteristics, including elemental composition, chemical structure, anti-oxidative activity, optical characteristics and so on. These characteristics were characterized by high-pressure exclusion chromatography, elemental analysis, Fourier transform infrared spectroscopy, UV-vis spectrum, fluorescent spectrum and photodegradation kinetics, respectively. The results showed that HA molecular weight was decreased and centralized when the concentration ratio of HA to NaOCl increased from 0 to 20.0μmol/mg. The polarity of the HA was first increased and then decreased, resulting from the evolution of the aromatic acids, fatty acids, phenols, alcohols and other oxygen containing components. It is noteworthy that the humification characteristics of the HA was not changed by NaOCl varied in the dose range used here, although the light absorption ability, antioxidant capacity and aromaticity was decreased, and the fluorescence intensity and apparent photosensitization activity was significantly enhanced. The results of this study can extend our knowledge on the structure of dissolved organic matter altered by deep oxidation treatment, and provide basic information for assessing the environmental effects of the effluent dissolved organic matter.%以腐殖酸(HA)作为溶解性有机质模型化合物,采用高压排阻色谱、有机元素分析、傅里叶红外光谱、紫外-可见光谱、荧光光谱及光降解动力学等手段研究了NaOCl对HA元素组成、结构特征、抗氧化性及光学特性等的影响.结果显示,当NaOCl与HA的浓度比由0增至20.0μmol/mg时,HA的分子量逐渐减小,并趋于集中分布;HA中的芳香酸、脂肪酸、酚和醇等含氧组分先增多后减少,使得HA的极性呈现出先增大后减小的变化趋势.值得注意的是,尽管实验浓度范围内的NaOCl不改变HA的腐殖特性,但其能显著减小HA的吸光能力、抗氧化能力和芳香度,并增大HA的荧光发光强度和表观光敏化活性.研究结果能促进对深度氧化处理改变溶解性有机质结构的认识,并为污水处理厂出水中溶解性有机质的环境效应评估提供基础信息.
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