表面改性纳米零价铁与脱卤菌联合作用机制及其协同降解地下水中三氯乙烯的机理研究

Groundwater contamination by trichloroethylene (TCE) has become a globle environmental concern. The combination of nanoscale zero-valent iron (NZVI) technology and microbial remediation technology is emerging as a promising option for the remediation of TCE-contaminated groundwater. However, to date, the previous studies have not reached a consensus in regard to the effect of NZVI on the microbial activity (growth inhibition or stimulation), the efficacy of the combined technology and the underlying mechanisms. Besides, the use of surface-modified NZVI with varying physicochemical properties and the varying groundwater conditions in the engineering application would further add uncertainties to the above mentioned questions. Therefore, this project will systematically study the efficiency and mechanism of the synergistic degradation of TCE with different surface-modified NZVI and dehalogenating bacteria under groundwater conditions. The specific objectives of this project are to: 1) investigate the effects of modified NZVI (i.e., stabilizer-coated NZVI, noble-metal loaded NZVI and sulfide-modified NZVI) on the activity of dehalogenating bacteria and the underlying mechanisms; 2) study the influences of the modified NZVI particles on the TCE dechlorination (dechlorination efficiency, products and pathway) by dehalogenating bacteria and the mechanisms; and 3) investigate the single and interactive influences of various groundwater environmental factors (pH, temperature, ions, natural organic matter and other coexisting microorganisms) on the efficacy of TCE degradation by the combination of NZVI and dehalogenating bacteria. The project is expected to provide theoretical basis and technical support for the engineering application of surface-modified NZVI and dehalogenating bacteria for the remediation of TCE-contaminated groundwater.

三氯乙烯引起的地下水污染已成为一个全球关注的环境问题。纳米零价铁与微生物联合修复技术在三氯乙烯污染治理中应用前景良好。然而，目前国内外对于纳米零价铁的微生物效应（生长抑制/刺激）及其与微生物联合修复技术的效能与机制仍存在争议。此外，工程应用中不同改性纳米零价铁物化特性和水环境条件各异更增加了上述问题的不确定性。为此，本项目将系统研究地下水环境条件下不同改性纳米零价铁与脱卤菌协同降解三氯乙烯的效能与机制。着重探究①不同改性纳米零价铁（稳定剂修饰型、贵金属负载型、表面硫化型）对脱卤菌活性的影响及机制；②改性纳米零价铁对脱卤菌脱氯性能、脱氯产物及脱氯路径的影响及机制；③地下水环境要素（pH、温度、阴阳离子、天然有机物、其它共存微生物等）对改性纳米零价铁与脱卤菌协同降解TCE效能与机制的单一影响和交互影响。项目有望为改性纳米零价铁与脱卤菌联合修复三氯乙烯污染地下水工程应用提供理论依据与技术支撑。

本项目系统考察了纳米零价铁（nZVI）和不同表面改性nZVI（表面硫化型、稳定剂修饰型、贵金属负载型等）的物化特性，及其反应活性和微生物毒性；系统考察了复杂水环境条件（如地下水阴阳离子，天然有机物，不同pH）对其物化特性和反应活性、微生物毒性的影响及其机制；比较分析了nZVI和表面改性nZVI在典型地下水环境老化过程中的物理化学特性演化，及其对反应活性和微生物毒性的影响；考察了表面改性nZVI联合脱卤菌协同降解三氯乙烯 (TCE) 的效能和作用机制。本项目的开展为发展不同改性nZVI及其与脱卤菌联用技术有效应用于TCE污染地下水的原位修复提供了重要理论依据和技术支撑，并有助于加深对不同类型nZVI环境行为的理解，对合理评估环境修复过程中不同类型nZVI潜在的环境安全性和生态系统风险也具有重要的参考意义。基于该项目研究结果，主持人以第一作者/通讯作者发表SCI论文35篇，其中一区论文28篇（包括3篇Water Research（IF=13.4），6篇Chemical Engineering Journal (IF=16.744)，6篇Journal of Hazardous Materials (IF=14.224)）；另外，其中3篇论文多次入选ESI高被引论文；申请5项国家发明专利，已授权2项；获得2019年度教育部高等学校科学研究优秀成果奖自然科学奖二等奖；获得2021年度中国有色金属科技成果奖二等奖；“地下水污染原位修复”项目获得2021年国家自然科学基金-优秀青年科学基金资助。