【作者】 曾睿；

【导师】 吴耀国；

【作者基本信息】 西北工业大学 ， 环境工程， 2007， 硕士

【摘要】 为了考察反硝化条件下表面活性剂对疏水性有机物污染物生物降解的影响，选择LAS（十二烷基苯磺酸钠）、Tween80（吐温80）分别作为阴离子表面活性剂与非离子表面活性剂的代表，以苯为典型污染物，进行了微环境模拟实验研究。围绕表面活性剂对污染物在土壤中吸附以及对微生物活性的影响，研究了LAS和Tween80存在下苯在河流沉积物中吸附行为的变化以及反硝化条件下LAS和Tween80存在体系中苯的生物降解，探讨了表面活性剂对污染物的固-液分配和可生化性的影响；讨论了反硝化条件下硝酸盐和表面活性剂对微生物活性的联合影响，并比较了该两种表面活性剂对污染物影响的作用机制，得到的主要结论如下： 1．LAS和Tween80对苯在渭河河床沉积物上吸附影响的实验研究结果表明，LAS和Tween80显著抑制沉积物对苯的吸附，该抑制作用与表面活性剂浓度呈正相关。与LAS相比，Tween80更利于苯从沉积物中解吸。 2．通过LAS的微环境实验表明，生物降解是苯被去除的主要原因。在一定NO₃^-浓度下（398mg/L～885mg/L），当LAS低于1CMC（临界浓度）时，LAS可促进苯降解，且浓度为500mg/L时的促进作用最佳；当浓度高于1CMC后，LAS则对苯生物降解产生一定抑制作用。硝酸盐浓度和苯的初始浓度对苯降解也有一定影响，当COD/NO₃^-在0.9～2.7之间时，苯的降解速率较高。 3．通过Tween80的微环境实验发现，初始阶段Tween80对苯在土/水系统中的降解没有促进作用，但就整个反应过程来看，Tween80可促进苯的降解。与LAS的促进作用不同，Tween80在低于1CMC时可促进苯的降解，在高于1CMC(15mg/L后，一定浓度内仍对苯有促进作用，且随Tween80浓度升高有所加强，至约2CMC时Tween80的促进能力达最大，当再升至5CMC（75mg/L）时促进作用则减弱，表现出Tween80对苯降解的影响与其浓度的密切相关。这可能和微生物对Tween80与苯之间的碳源竞争、Tween80与苯被利用时对硝酸盐（电子受体）的分配作用，以及Tween80的生物毒性等有关。更多还原

【Abstract】 In this study a microbial system for benzene biodegradation is set up in order to investigate the efftcts of surfactant on degradation of hydrophobic organic compounds in the soil-water system under the denitrification condition. Based on the influence of surfactant on interface behavior of benzene in soil and microorganism activity, the sorption behaviors and the degradation of benzene in sediment when the anionic surfactant （LAS） or nonionic surfactant （Tween80） exists were investigated. The effect on the existent form and degradability of benzene by surfactants and the mechanism of surfactants and nitrate affected the microorganism activity under the denitrification condition were discussed. The different influences between LAS and Tween80 on benzene sorption and degradation were compared. The main conclusions of this work are drawn.1. The influences of surfactants on benzene sorption in Weihe river sediment were investigated. LAS and Tween80 could obviously reduce the sorption of benzene onto soil and the effect is enhanced with the concentration of surfactants increasing. The desorption of benzene from soil is more strongly when Tween80 exists than LAS added into the soil. The effect of LAS on sorption of benzene is lower than that of Tween80 when the concentration of surfactants higher than 1CMC but lower than 2CMC.2. Based on microcosm tests, we simulated and studied benzene degradation when LAS exists under denitrification condition. The results showed the biodegradation is major action in removing benzene. The degradation rate could be increased by LAS when the concentration of LAS lower or appreciably higher than 1CMC, but the rate could be decreased if the concentration higher than 1CMC. Nitrate concentration and benzene origin concentration could effect the benzene degradation process, the degradation rates were higher when the COD/NO₃^- among 0.9-2.7 than in other case.3. Tween80 had unobvious or suppressive effects on benzene degradation in first days, but it could improve degradation rates in the whole degradation process, based on microcosm tests. The degradation rate could be increased by Tween80 when its concentration lower or higher than 1CMC （15mg/L）, but the rate could be decreased if the concentration higher too much. For example, when the concentration was 5CMC, the degradation rate was lower than that at 1CMC, which maybe because of the更多还原