【作者】 宋赛赛；

【导师】 朱利中；

【作者基本信息】 浙江大学 ， 环境科学， 2014， 博士

【摘要】 我国一些地方土壤重金属-有机物复合污染呈加重趋势,影响农产品安全和土地资源的持续利用,亟需发展经济高效的复合污染土壤修复技术。本文在评述重金属-有机物复合污染土壤修复技术研究现状的基础上,重点研究了天然生物表面活性剂皂角苷对多环芳烃(PAHs)的增溶作用及影响因素；深入研究了皂角苷同时增强洗脱复合污染土壤中重金属和PAHs的作用机制；初步探讨了皂角苷强化植物修复复合污染土壤的效果,试图为开发经济高效的复合污染土壤强化修复技术提供理论基础。论文取得了以下主要成果：(1)皂角苷通过分配作用增溶PAHs于胶束内部,同时胶束外部的亲水链上羟基和羧基可络合重金属离子。皂角苷对PAHs的增溶能力随介质pH值升高而降低,随离子强度和温度的升高而增大,环境中共存重金属离子可提高皂角苷对菲的溶解度；皂角苷与四种重金属离子的络合稳定常数大小次序为：Pb2+>Cu2+>Zn2+>Cd2(2)发现皂角苷能高效洗脱复合污染土壤中PAHs,同时有效去除土壤中重金属离子。皂角苷增溶洗脱复合污染土壤中菲和芘的效率均可达到90%左右,PAHs之间不存在竞争作用；皂角苷对Cd-菲复合污染土壤中Cd的洗脱效率可达87.7%,而对重金属-PAHs复合污染土壤中Cd的洗脱效率为55.8%,同时对Cu、Zn和Pb的去除率分别为58.1%、47.8%和22.1%,多种重金属离子之间则存在竞争络合现象。(3)发现皂角苷能促进黑麦草修复Pb-芘复合污染土壤。浓度为2000mg/kg时,种植30天后黑麦草根系和茎叶中Pb浓度分别达到1135.4mg/kg和231.4mg/kg,比空白对照增加了1.1倍和11.8倍；1000mg/kg皂角苷促进黑麦草修复复合污染土壤中芘的效果最好,土壤中芘的残留浓度为35.6mg/kg,比对照降低了43.0%。更多还原

【Abstract】 The co-contaminated soils by heavy metals and persistent organic pollutants is a widespread environmental problem as the result of numerous industrial activities and rapid urbanization. Based on the review of remediatiaon of co-contaminated soils, This thesis studied the effect of saponin on remediation of PAHs and heavy metal co-contaminated soil, including the effect of environment factors on the solubility of PAHs, the complexation of heavy metals by saponin, the role and mechanism for biosurfactant saponin to enhance the desorption of heavy metals and PAHs from co-contaminated soils and the effect of saponin on the remediation of co-contaminated soils by plant. The main results of this thesis are shown below:(1) Saponin can effectively solubilize PAHs and complex heavy metals due to the complexation of heavy metals with the external carboxyl or hydroxyl groups of saponin micelle, on the other hand, it can incorpoate or partition of PAHs within saponin micelles. The solubilization capabilities of saponin for PAHs decreased with the increase of pH in solution, but increased with the increase of temperature and ionic strength. The conditional stability constants for saponin complexation of heavy metals were followed the order of Pb2+>Cu2+>Zn2+>Cd2+.(2) Saponin can effectively remove PAHs and heavy metals from the co-contaminated soils. The remove rates of PAHs by saponin were about90%, while the remove rates of Cu, Cd, Zn and Pb were58.1%,55.8%,47.8%and22.1%. This behavior was generally attributed to the PAHs had no competition each other, while the heavy metals had the competition with each other.(3) The presence of saponin can significantly enhance plant uptake of Pb and pyrene from the co-contaminated soils. With addition of saponin at2000mg/kg, the concertration of Pb in ryegrass roots and shoots were1.1and11.8times compared with the treatment without addition of saponin, respectively. The residual concentration of pyrene in soil was35.6mg/kg, which was about43.0%lower compared with the control.更多还原