【作者】 张栋；

【导师】 朱利中；

【作者基本信息】 浙江大学 ， 环境科学， 2013， 博士

【摘要】 表面活性剂增效生物修复(SEBR)是最具发展潜力的有机污染土壤修复技术之一。人们研究发现表面活性剂能增溶洗脱、促进微生物降解有机污染物,强化修复有机污染土壤。但迄今表面活性剂对污染物的土-水界面,特别是微生物-水界面行为的调控及其机制仍不完全清楚。为此,本文在评述微生物降解土壤有机污染物相关界面行为的基础上,研究了表面活性剂对多环芳烃(PAHs1在土壤-溶液-细菌等界面迁移转化行为的影响及调控机制,试图为发展经济高效的有机污染土壤修复技术提供科学依据。论文取得了一些有价值的结果：(1)发现鼠李糖脂-Tween80混合表面活性剂能协同增强洗脱土壤中PAHs,其洗脱效率和速率与混合表面活性剂组成相关,质量比1:9的鼠李糖脂-Tween80对土壤中菲和芘的最大洗脱效率分别是单一表面活性剂之和的1.16和1.19倍；达到相同洗脱效果(约60%),混合表面活性剂的用量仅为单一表面活性剂的三分之一；混合表面活性剂还能显著降低阴离子表面活性剂的生态毒性。(2)阐明了表面活性剂增强细菌(Klebsiella oxytoca PYR-1)表面吸附是促进PAHs降解的前提,降解率增加值(Bd*/Bd)与细菌吸附系数增加值(Kd*/Kd)呈线性正相关：Bd*/Bd=0.636Kd*/Kd+0.390(P<0.0001).揭示了表面活性剂促进细菌吸附PAHs的作用机制,即表面活性剂分子吸附在细胞表面亲/疏水点位,改变细胞表面疏水性,提高了菌体吸附PAHs的能力；其程度与表面活性剂的HLB值相关,随HLB值减小(烷基链增大),新增疏水点位对芘的分配能力越强。(3)揭示了表面活性剂对细菌细胞膜性质及PAHs跨膜传输的影响。发现Tween80等表面活性剂可诱导细胞膜不饱和脂肪酸含量的增加,提高细胞膜通透性,有利于PAHs的跨膜传输；而Triton X-100则会破坏细胞的完整性,影响其正常功能。更多还原

【Abstract】 Surfactant-enhanced bioremediation (SEBR) has been considered as a promising technology for the treatment of organic contaminated soil. It is found that surfactants enhanced the desorption of hydrophobic organic compounds (HOCs) from soil matrix, as well as the biodegradation of HOCs. However, litter information on the surfactants controlling the HOCs behaviors in multiple interfaces such as soil-water and microbe-water interfaces and underlying mechanisms is available. Based on the review of interfacial processes of HOCs biodegradation and the surfactant affect, this thesis systematically studied the effects and controlling mechanisms of surfactants on the soil-water-bacteria interfacial processes of PAHs, such as soil-water desorption, bacteria-water sorption and transmembrane transport. The main results of this thesis are shown below:(1) Rhamnolipid-Tween80mixed surfactants synergistically enhanced the washout of PAHs from contaminated soils, and the washing rate as well as the efficiency positive correlated with the compose of mixed surfactants. The mixed surfactant of rhamnolipid and Tween80with1:9ratios did synergistically enhance the washing efficiency,1.16and1.19times higher than the sum of single surfactants for phenanthrene and pyrene, respectively. Compared with single rhamnolipid and Tween80, the volume of mixed surfactants was less than one third with the same efficiency (60%). Furthermore, the addition of nonionic surfactant significantly reduced the bacterial toxicity of anionic surfactants, such as SDBS and rhamnolipids.(2) It was illustrated that the influence of surfactants on the bacterial sorption of PAHs was the premise of their effects on PAHs biodegradation. A highly correlation between biodegradation enhancement (Bd*/Bd) and sorption improvement (Kd*/Kd) in the presence of surfactants was found. In the presence of surfactants, the biodegradation efficiency of PAHs could be predicted as Bd*/Bd=0.636Kd*/Kd+0.390(P<0.0001). The mechanisms of surfactant-enhanced bacterial sorption of PAHs were also explored:the interactions between surfactant molecule and bacterial surface resulted in changes of cell surface hydrophobicity (CSH) and consequent enhancement of sorption ability. The extents of CSH and bacterial sorption ability for PAHs were correlated with the HLB values negatively (or alkyl chain long positively).(3) Surfactants could affect the bacterial membrane properties and the transmembrane process of PAHs. It was found that surfactants such as Tween80induced the production of unsaturated fatty acid in bacterial membrane. These resulted in the increase of membrane permeability, facilitating the transmembrane transport of PAHs. However, disrupted the cell membrane and affected adversely the foundational functions due to its powerful solubilization property.更多还原