【作者】 陈宝梁；

【导师】 朱利中；

【作者基本信息】 浙江大学 ， 环境科学， 2004， 博士

【摘要】 修复和缓解土壤有机污染是环境科学和工程等领域急待解决的热点问题之一。表面活性剂在土壤有机污染修复／缓解中具有巨大的应用潜力，特别是表面活性剂增强修复（Surfactant-enhanced Remediation，SER）有望成为土壤有机污染修复的实用技术。 本文在评述表面活性剂在土壤有机污染修复中的应用及机理的基础上，围绕表面活性剂对有机污染物在土壤／水界面间吸附行为的影响这一中心，深入探讨了表面活性剂-土壤-水-有机污染物复杂体系中多界面、多过程的吸附行为。重点研究了阳离子表面活性剂对土壤／粘土截留固定各种极性有机污染物的增强效应、机理及影响因素，特别是吸附态表面活性剂的吸附机理和临界固定浓度；研究了阴、非离子表面活性剂对有机污染物的增溶和洗脱作用，深入探讨了表面活性剂的临界洗脱浓度及其影响因素。系统地研究了表面活性剂的增溶作用（动力学、热力学）、在土壤上的吸附、洗脱或固定土壤中有机污染物、表面活性剂的回收等内容，试图为表面活性剂在土壤有机污染修复／缓解中的应用，拟订快速、经济、有效的土壤有机污染修复的实用技术，同时为土壤污染地区有效控制农产品污染、生产优质农产品提供理论依据。论文取得了一些创新性的研究成果。 （1）阳离子表面活性剂（MPB）能显著增强土壤吸附固定对硝基苯酚、苯酚、萘等有机污染物，吸附机理为土壤SOM和吸附态MPB烷基链形成有机相的双分配作用，表观分配系数K_d^*=K_ocf_oc+K_oc^*f_oc^*；K_d^*增大源于土壤有机碳含量f_oc^*提高和MPB烷基链形成的有机相分配能力K_oc^*增强(K_oc^*比K_oc约大10～25倍)；最佳的截留固定作用(K_dmax^*／K_d比值)与MPB的饱和吸附量Q^o呈正相关，与土壤本身有机碳含量(f_oc)呈负相关。 （2）发现吸附态MPB提供的有机碳(f_soc)标化的吸附系数(K_ss)不为常数，而随f_soc出现规律性变化；据此，提出了吸附态表面活性剂的“吸附结构模型”，即在低吸附量时，形成了一层薄薄表面吸附膜（Thin Adsorptive Film），对有机物产生较强的表面吸附作用；在较高吸附量时，表面吸附膜逐渐转化成吸附能力相对较弱的分配相（Partition Phase），对有机物产生分配作用。用XRD、FTIR谱图证实了吸附态MPB从低覆盖量的“表面膜”逐渐演变到高覆盖量的“分配相”。暴中文摘要 （3）提出了有机物在表面活性剂一土壤一水体系中的“四角锥”分布模型，探讨了PAHs在非离子表面活性剂（TX一100）一土壤一水体系中多界面、多过程的吸附行为;溶解态的表面活性剂提高PAHs溶解度，有利于洗脱作用，吸附态的则增强RAHs的吸附作用，不利于洗脱作用;表面活性剂洗脱土壤中有机污染物的必要条件是关rKs扩Kd<火石nK山n+方补沪场c，进而提出了表面活性剂在土壤有机污染修复中的临界洗脱浓度（Critieal Deso印tion Concentratlons，CDC）概念，探讨了CDC的影响因素及机理;表面活性剂CDC值随有机污染物溶解度降低和土壤有机碳含量升高而降低。更多还原

【Abstract】 The widespread occurrence of many persistent toxic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), in soils and groundwater has become a serious environmental concern, which has led to intensive studies of the transport, bioavailability, fate and potential remediation technology of these contaminants in subsurface environment. The ability of surfactants to enhance the aqueous solubility of nonionic organic compounds (NOCs) or to promote immobilization of NOCs offers a potential means of remediating contaminated soils and groundwater by use of surfactant solutions. There has a great interest in surfactant-enhanced remediation (SER) in recent years.In this dissertation, the application of surfactant to soil organic pollution remediation and its mechanisms were reviewed. Based on the influence of surfactant on interface behavior of organic contaminants between soil and water, the multiprocess among multimedia including surfactant-soil-water-organic pollution was investigated. The influential factors of myristylpyridinium bromide (MPB), a cationic surfactant, on enhanced-immobilization of nonpolar and polar organic contaminants onto soils and bentonites and their mechanisms were studied; sorption mechanisms of mineral-sorbed surfactant and critical immobilization concentration of surfactant were discussed. Solubility enhancement in aqueous solution and desorption enhancement from soil by anionic and nonionic surfactant were also studied; the critical desorption concentrations (CDC) and its influential factors were discussed. Through simulating desorption solution with organic pollutant and surfactant, removal efficiency of organic pollutant and recovery efficiency of surfactant from the simulated solution by air-stripping and liquid-liquid extraction methods were elementarily researched. The observations in this work will provide a reference to use of surfactants for remediation of contaminated soils or groundwater in engineered surfactant-enhanced washing/immobilization, and offer a theoretical gist for guaranteeing quality of the agricultural products in organic contaminated regions. The main original conclusions of this work are drawn.(1) The sorption capacities of naphthalene, phenol, and p-nitrophenol on MPB-sorbed solids are much higher than on MPB-free solids. The Kd* values, the ratio of bound NOC to mobile NOC, for naphthalene, phenol, and p-nitrophenol were calculated. Kd* = Kocfoc + Koc*foc*, which indicated that sorption mechanisms of NOC on MPB-sorbed solid was dual-partition into soil organic matter (SOM) andMPB-derived organic matter. The enhanced-sorption of NOCs was contributed to increasing both soil total organic carbons contents (foc*) and partition capability (Koc*). The ratio of Koc* to Koc for NOCs are approximately to 10-25. The optimal immobilization (Kdmax*/Kd ratio) was positive relative to MPB saturated sorption amount, and negative relative to soil organic carbon contents (foc).(2) Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. At low sorbed-surfactant levels, the resulting mineral- adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulk-like medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The structure transition of mineral-sorbed MPB was verified by XRD and FTIR.(3) A "Tetragonal" distribution model was suggested to discuss multiprocess of PAHs among multimedia including soil-surfactant-water. The surfactant dissolved in water enhances contaminant solubility, favoring更多还原