典型复合污染地下水中多环芳烃的竞争吸附/解吸机理

Adsorption-desorption are the most influential factors of restricting the migration and transformation of PAHs in the shallow groundwater, which are non-degradable organic pollutants. By now, the study on its competitive adsorption-desorption in the combined polluted groundwater is still at its preliminary stage,and has many controversies. The difficult of study is the quantitative analysis of the competitive adsorption-desorption because of the many kinds of containants and the mechanism of complicated interaction. Therefore, on the basis of previous research on PAHs adsorption-desorption in our laboratory in the non-pollution water environmental, this study selects groundwater with combined pollution field in Lanzhou city of the terrace of the Yellow river as the subject and analyzes the influence of composite pollutants on the competitive adsorption-desorption of PAHs in the aquifer under the coexistence circumstances by combining the outdoor & indoor experiments and employing the field detected system, GC-MS, SEM, triaxial permeameter and others' instrumentations. Based on sifting the influencing factors and setting major influencing parameters, emphasis has been put on the quantitative relations between influencing factors and competitive adsorption-desorption and the coupling of the competitive adsorption-desorption parameters of PAHs into hydro-dynamic dispersion model has been put forward, which could reveal the migration and transformation rules of PAHs in the pore aquifer with multiple contamination and provide scientific basis for the treatment of non-degradable organic pollutants in the shallow groundwater.

多环芳烃（PAHs）作为难降解有机污染物，吸附/解吸是制约其在浅层地下水中迁移转化的重要作用。目前针对PAHs复合污染地下水中的吸附/解吸研究尚处于起步阶段，主要因为复合污染地下水中污染物种类繁多、作用机理复杂，使定量分析竞争吸附/解吸机理成为相关研究的难点。本项目以前期PAHs在超纯水中的吸附/解吸机理研究为基础，以兰州黄河Ⅰ、Ⅱ级阶地典型石化场地复合污染河谷潜水为研究对象，采用示踪实验、静态实验和动态实验方法，应用现场检测硬件系统、GC-MS、扫描电镜、加压三轴渗透仪等先进仪器，分析共存条件下复合污染物与PAHs在含水层中的竞争吸附/解吸行为，识别松散岩类孔隙水中PAHs吸附/解吸的主要影响因素，进而重点研究共存污染物与PAHs竞争吸附/解吸机理，提出竞争吸附/解吸机制模型耦合的方法，揭示复合污染孔隙含水层中PAHs的迁移转化规律，为难降解有机污染物在浅层地下水中污染控制提供理论依据。

化工区复合污染地下水有机污染物的迁移转化机理研究是目前水文地质研究的重要内容，本项目的研究，基于兰州市石油化工污染场地地下水环境状况、污染物演化特点及水文地质条件，选取选择代表性2环芳烃萘（NAPT）、3环芳烃菲（PHEN）为典型PAHs，开展了复合污染条件下PAHs在浅层地下水中的竞争吸附/解吸行为研究，通过室内实验，分析了温度、pH值、氧化还原电位、矿化度、硝酸盐、硫酸盐、重金属等因素的影响规律，确定了主要因素，通过静态实验和动态实验，分析了PAHs与特征污染物在优势影响因素下的交互作用和竞争机制，并建立了PAHs在复合污染地下水中的吸附/解吸耦合模型，上述研究成果促进了复合污染地下水中有机污染物迁移机理的研究，为难降解有机污染物在浅层孔隙水中的污染修复提供理论依据，已取得一批有特色、有影响的成果，项目按计划开展工作，执行结果主要反映在出版著作1本，论文3篇，专利授权5项，受理审查发明专利1项。