表面活性剂强化活化过硫酸钠原位修复典型POPs污染场地的机理和调控机制研究

POPs (Persistent Organic Pollutants) contaminated land is a serious environmental problem in China, endangering public health and environmental safety. This project aims to provide a safe and efficient solution to the above problem using DDT and PCBs as the model compounds for POPs. Considering POPs' high toxicity and environmental resistance to chemical and biological degradation, this project studies the remediation and dechlorination of POPs by activated persulfate chemical oxidation; because sorption of highly hydrophobic POPs to soils is a significant limitation for the in situ chemical oxidation of POPs, this project studies using surfactants to enhance the solubility of POPs and accelerate the remediation process. Over three years, this project will thoroughly investigate the mechanism and regulation of the Surfactant Enhanced Activated Persulfate Remediation of POPs contaminated land. Specific objects are to:(1)study the compatibility between surfactants and oxidants,and the solubilization of DDT and PCBs from soils enhanced by the surfactants;(2)study the remediation process of DDT and PCBs in surfactant-water system, characterize the degradation kinetics and regulation mechanism, clarify the degradation pathways and mechanism, and optimize the remediation process;(3)study the remediation process of DDT and PCBs in a slurry system by Surfactant Enhanced Activated Persulfate Oxidation, characterize the degradation kinetics and regulation mechanism, and clarify the synergetic mechanism between surfactants and the oxidant. Overall,the results of this project will provide a safe and efficient solution to the remediation of POPs contaminated land, and accelerate its remediation process.

POPs污染场地对人民健康和生态安全构成了巨大威胁。本项目以DDT、PCBs作为典型POPs的代表，拟开展活化过硫酸钠原位氧化清除典型POPs及其与表面活性剂协同作用机理研究。针对POPs高毒性、难降解的特点，研究活化过硫酸钠原位氧化POPs实现脱氯毁毒的过程；针对POPs强疏水性、难溶的特性制约其原位氧化的高效进行，研究表面活性剂促进POPs氧化降解的过程和机制。重点在于：（1）研究表面活性剂和过硫酸钠的兼容性，表面活性剂对DDT、PCBs的增溶洗脱规律；（2）研究活化过硫酸钠降解表面活性剂洗脱的DDT、PCBs的过程，降解动力学规律及影响因素，降解途径和机理；（3）研究表面活性剂协同活化过硫酸钠原位修复POPs污染土壤的过程，降解动力学规律及影响因素，表面活性剂和活化过硫酸钠的协同机制。本项目研究有望为POPs污染场地修复提供一种安全、高效的方法,加快污染场地环境无害化治理进程。

原位化学氧化修复技术（ISCO）是有机污染地下水和场地修复研究和应用的新兴热点。传统ISCO技术场地修复效果往往受到疏水性有机污染物（HOCs）的低水溶性、强疏水性及多相体系氧化剂分布不均匀等因素的限制，HOCs降解效果往往难以保证。针对上述问题，本项目着重研发新流程强化复杂水土多相体系物质传质、促进疏水性有机污染物（HOCs）解吸、调控氧化剂活化，构建通用、安全、高效原位有机污染土壤和地下水一体化修复技术。具体分别开展了通过表面活性剂、超声、传统加热及微波加热等方法促进活化过硫酸钠氧化降解地下水和土壤高浓度有机污染物的研究，在构建高效活化过硫酸钠场地修复技术体系方面取得重要进展，重要进展分述如下：.1.研究了常见非离子及负离子表面活性剂和热活化过硫酸钠的兼容性，优化筛选出对过硫酸钠具有优良稳定作用的十二烷基二苯醚二磺酸钠；通过水相研究阐明活化过硫酸钠能降解十二烷基二苯醚二磺酸钠增溶的HOCs（PAHs及PCBs作为代表性HOCs）过程和机理；利用表面活性剂及提高反应温度协同促进HOCs的解吸是实现其高效降解的关键。.2.利用超声及其热效应，能有效强化水土多相体系传质、活化过硫酸钠、促进HOCs解吸，进而构建HOCs解吸及氧化降解的正反馈循环，实现土壤吸附的高浓度HOCs快速降解。.3.采用微波热活化过硫酸钠能显著提高水土多相体系HOCs的降解效率，其关键是利用微波对水及过硫酸钠的高效加热，活化过硫酸钠、强化传质及促进HOCs解吸；此外研究还揭示微波的非热效应具有促进过硫酸钠活化及加速HOCs降解的效果。.4.针对污染场地和地下水的关注污染物甲基叔丁基醚（MTBE）、六六六（HCHs）、邻苯二甲酸酯代表性污染物DMP，分别优化筛选了目标污染物的活化过硫酸钠氧化降解方案，阐明目标污染物的降解过程及机理，实现上述各类污染物的高效降解，为上述各类有机污染地下水及场地修复选择合适的活化过硫酸钠修复方案提供技术支撑。