城市污水中典型卤代苯酚分布及其光降解行为研究

卤代苯酚(HPs)是一类广泛存在于水体中的污染物,其在污水处理厂出水中的存在及迁移转化会产生一定的健康和生态风险。探究卤代苯酚在环境中的转化行为非常重要。光降解反应是酚类物质在水体中迁移转化的重要途径,实际水体中的有机质等对卤代苯酚的光降解会产生一定的影响。对大连市区6家污水处理厂出水中卤代苯酚的污染状况进行了调查,结果显示在所有出水中总HPs的浓度范围为77.2~168.6 ng·L-1。在所有检出的卤代苯酚中,五氯酚和2,6-二氯酚浓度较高,且检出频率均为100%,检出浓度范围分别为10.8~166.7 ng·L-1和0.1~72.2 ng·L-1。在模拟太阳光照射条件下,选取2种氯酚和2种溴酚研究它们在污水样品与纯水中光降解行为,从卤原子取代的程度和种类两方面对不同卤代苯酚光降解的规律进行类比,分析了其光降解特性。此外,对比分析了不同污水厂出水的对同种卤代苯酚降解速率的影响,发现出水的p H值、溶解性有机质等因素,都可能影响卤代苯酚的光降解。

Distribution and Photodegradation of Typical Halophenols in WWTP Effluents of Dalian

The presence of halophenols (HPs) in aquatic environment is ubiquitous and has attracted increasing concerns due to their toxicity, mutagenicity, and carcinogenicity. The fate of HPs in the environment is of great importance and should be constantly monitored. Photodegradation is one of the main elimination pathways of HPs in water environment and is influenced differently by different organic matters in water environment. In this study, effluents water were collected from 6 waste water treatment plants (WWTPs) of Dalian and the photodegradation of selected HPs in the solution of effluents under simulated sunlight irradiation was investigated. The results showed that the concentration of HPs ranged from 77.2 to 168.6 ng L^-1 in all the 6 WWTPs. PCP and 2,6-DBP were the most abundant with the concentration of 10.8 to 166.7 ng L^-1 and 0.1 to 72.2 ng L^-1. Four HPs were selected to degrade in the effluents of 3 WWTPs and ultrapure water under simulated sunlight. Different numbers and kinds of halogen atoms of the compounds could affect the degradation constant of HPs. In addition, the effects of different effluents on the degradation rate of the same kind of halogenated phenols were compared and analyzed. It was found that the pH value of the effluents, the dissolved organic matter and other factors may also affect the photodegradation rate constant of halophenols.