【作者】 吴应琴；

【导师】 陈慧；

【作者基本信息】 西北师范大学 ， 分析化学， 2007， 硕士

【摘要】 本文针对多环芳烃水溶性低、吸附性强和生物可利用性低的特点,以及常用增溶剂-化学表面活性剂难以微生物降解,可引起环境二次污染的现状,系统研究了生物表面活性物质皂角苷和腐殖酸对疏水性难溶有机污染物多环芳烃的增溶作用及机理;重点比较了皂角苷和腐殖酸与化学表面活性剂的增溶能力;研究了皂角苷-非离子混合表面活性剂对多环芳烃的协同增溶作用;首次提出以皂角苷和腐殖酸为增溶剂,研究了它们对多环芳烃-蒽微生物降解过程的影响,并与非离子化学表面活性剂Tween80作了相应的比较。试图找出新型、高效的增溶试剂和增溶体系,降低修复成本,提高修复效率,为高效、快速、安全、实用的表面活性剂增效修复技术提供理论依据。第一章表面活性物质增效修复多环芳烃污染土壤及地下水的研究进展多环芳烃由于其致癌性、致突变性而受到广泛关注。本文介绍了多环芳烃的来源、种类、分布及性质,阐明了多环芳烃对人体的危害,并介绍了多环芳烃污染的化学修复、生物修复、化学与生物相结合的修复机制。概述了近年来在多环芳烃污染土壤及地下水修复中关于表面活性剂的研究进展,探讨了提高多环芳烃修复速率的途径及其存在的一些问题,同时展望了今后的发展趋势。第二章生物表面活性剂-皂角苷对多环芳烃的增溶作用比较了生物表面活性剂-皂角苷（Saponin）与两种化学表面活性剂-聚氧乙烯月桂醚（Brij35）和曲拉通100（TX100）对多环芳烃（PAHs）蒽和菲在水溶液体系中的增溶作用及皂角苷与三种化学表面活性剂-聚氧乙烯月桂醚（Brij35）、曲拉通100（TX100）和十二烷基硫酸钠（SDS）对土壤中多环芳烃蒽和菲的解吸行为的影响。结果表明,在水溶液体系中,当表面活性剂的浓度在其临界胶束浓度（CMC）以下时,对蒽和菲的增溶程度较弱,增溶顺序为:Saponin＞Brij35＞TX100;在CMC以上时,表面活性剂对蒽和菲产生显著的增溶作用,增溶顺序为:Brij35＞Saponin-＞TX100。当皂角苷与化学表面活性剂溶液混合时,混合溶液的胶束/水中溶质的分配系Kmc增大,对蒽和菲产生协同增溶作用,其顺序为:Saponin-Brij35＞Saponin-TX100,协同增溶程度在19.97-87.19%之间。同样,在水-土体系中发现,当表面活性剂的浓度低于或接近于CMC时,对PAHs的解吸没有明显的促进作用,当表面活性剂的浓度高于CMC后,表面活性剂对土壤中PAHs的解吸过程有显著的促进作用。第三章腐殖酸对多环芳烃的增溶作用及其影响因素对比研究了腐殖酸（HA）及3种非离子表面活性剂（Tween20、Tween80、TX100）对典型的多环芳烃蒽的增溶性,并探讨了离子强度、共存有机物对腐殖酸增溶多环芳烃行为的影响。实验发现,当表面活性物质浓度大于临界胶束浓度（CMC）时,腐殖酸及3种非离子表面活性剂对多环芳烃均有较好的增溶效果,而且溶解度与表面活性物质浓度成正比线性相关,其增溶效果为HA＞Tween20＞Tween80＞TX100。由于腐殖酸与化学合成表面活性剂相比易于生物降解,因此腐殖酸可以作为一种理想的化学表面活性剂的替代品来处理多环芳烃污染比较严重的土壤。第四章蒽在腐殖酸溶液中的增溶热力学及动力学本文研究了疏水性污染物蒽在腐殖酸溶液中的溶解热力学及动力学特征。研究结果表明,腐殖酸对蒽有一定的增溶性,而且随着温度的升高,增溶程度增强。蒽在腐殖酸溶液中增溶行为为自发、吸热的熵增过程,△G^θ=-13.63 KJ·mol^-1,△H^θ=11.96 J·mol^-1,△S^θ=45.78 J·K^-1·mol^-1;在35℃、45℃下△G^θ分别为-14.09 KJ·mol^-1和-14.55 KJ·mol^-1。同时,用几种溶解动力学曲线对腐殖酸增溶蒽的溶解动力学曲线进行了拟合,结果表明腐殖酸增溶蒽的溶解动力学曲线更符合Elovich方程。第五章皂角苷及腐殖酸对微生物降解蒽的影响研究了皂角苷（生物表面活性剂）和腐殖酸（类表面活性物质）对微生物降解蒽的影响,并与Tween80（化学表面活性剂）对蒽的增溶及促进微生物降解的作用进行对比。结果表明,在不加任何表面活性物质时,微生物需要7d产生足够的糖脂使蒽溶解,并发生微生物降解。皂角苷、腐殖酸和、Tween80均能较大程度的加速蒽的降解,而且在相同条件下皂角苷及腐殖酸的效果明显优于Tween80。腐殖酸及皂角苷大大缩短了微生物降解蒽的时间,在2～4d内蒽的降解率可分别达到98.2%和98.4%。同时发现腐殖酸的浓度、蒽的初始浓度均影响着蒽的微生物降解速率。更多还原

【Abstract】 Due to the characteristics of PAHs such as the low bioavailability, low solubility and strong sorption, the secondary contamination often occurred in the soil matrix if the remediation approach used the solubility-enhanced chemical surfactants that usually are non-biodegradable. In this paper, biosurfactants - humic acid and Saponin were chosen as the surfactants to be used in the flushing alternative of soils that were contaminated by hydrophobic and insoluble PAHs, and their effects on solubility-enhancement and reaction mechanisms were studied. In the comparision of solubilizing and washing efficiency by using the chemical synthetic surfactants - humic acid and Saponin, the solubilization of PAHs mixed with Saponin and nonionic surfactants were investigated focusing on the co-enhancement of solubility and reduction in partition of nonionic surfactants into organic phases. At last, biodegradation of anthracene in humic acid and Saponin solutions were determined and compared with chemical synthetic surfactant Tween80. The objectives of the present studies are to find the new, safe, economical and high-efficiency novel agents that can be used in the PAHs contaminated soils while the essential theory for the application are summarized.Chapter 1. Study on surfactant-enhanced remediation of soil and groundwater contaminated by Polycyclic aromatic hydrocarbonsPolycyclic aromatic hydrocarbons（PAHs） have been of a great interest in recent years because of their carcinogenic and mutagenic potential .A review on the source ,the kind ,the distribution and the property of PAHs was presented. And the mechanism of chemical、biological and chemical-biological remediations of organic contaminated soil and groundwater was introduced. Meanwhile the paper reviews the researchs on surfactants applied in the PAHs remediation in recent years and the prospects on this field are discussed.Chapter 2. Water Solubility Enhancement of anthracene and phenanthrene by biosurfactant -SaponinThe solubilizations of anthracene and phenanthrene were characterized, by using Saponin, and compared with three typical chemical surfactants （Brij35, TX100, SDS） in water solution and PAH-polluted soil. The results showed that a solubilization of anthracene and phenanthrene were dramatically enhance when dosages of surfactants were over their respective critical micelle concentration （CMC）, and their solubilization capabilities were as follows Brij35>Saponin>TX100. Furthermore, anthracene and phenanthrene were synergistically solubilized by mixed Saponin -nonionic surfactant solutions. It was indicated that the mixed Saponin and surfactants were attributed to the increase of partition coefficient （ Kmc） of solutes between micelle and aqueous phase. The efficiencies of synergistic solubilization were up to 19.97-87.19%. The desorption ratios of anthracene and phenanthrene in the soil were increased with the increase of Saponin and surfactant concentrations. Chapter 3. Water Solubility Enhancement of PAHs by using humic acidThe solubilization of anthracene was characterized by using humic acid in comparison with three typical nonionic surfactants （Tween20、Tween80、TX100）. The influences of inorganic salts and organic cosolutes on solubilization behavior were also investigated. The results showed that not only surfactants in the range of concentration above critical micellar concentration （CMC） but also humic acid could greatly enhance the solubilization of anthracene, and its solubility had the linear relationship with the concentration of surfactants or humic asid. The solubilization capabilities were as follows HA>Tween20>Tween80>TX100. The work presented here demonstrated that the natural HA could be an attractive alternative to synthetic surfactants in ex situ washings for PAH-polluted soils due to its additional capacity.Chapter 4. Solubilization thermodynamics and kinetics of anthracene in the presence of Humic AcidThe solubilization thermodynamics and kinetics of hydrophobic pollutants anthracene in the humic acid micellar solutions have been examined using batch tests. The results showed that the solubilization rate of athracene was significantly enhanced with increasing temperature. The solubilization process of athracene was spontaneous, exothermic and entropy increasing withΔG^θ= -13.63 KJ. mol^-1,ΔH^θ=11.96 J.mol^-1,ΔS^θ= 45.78 J/K, as well asΔG^θ= -14.09 and -14.55 KJ. mol^-1 in 35℃and 45℃, respectively. A Elovich kinetics model fitted the solubilization data of anthracene well.Chapter 5. Effect of Saponin and Humic acid on Biodegradation of AnthraceneThe influences of Saponin （biosurfactant） and humic acid （surfactant-like substance） on the biodegradation of anthracene were studied in comparison with Tween80 （chemical surfactant）.. The results indicated that it must take about 7d for microorganisms to produce the sufficient glycolipids to solubilize anthracene and made anthracene biodegradable in the absence of any surfactants. Saponin humic acid and Tween80 could be used to accelerate significantly biodegradation of anthracene, especially, Saponin and humic acid could dramatically shortened the onset time for biodegradation of anthracene, and the biodegradation rate could reach 98.2% and 98.4% within 2～4d, respectively. It was also discovered that the biodegradation of anthracene was affected by the concentrations of humic acid added and initial concentrations of anthracene.更多还原