| 污染场地卤代烃非生物自然衰减研究进展 |
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| 引用本文： | 廖高明,马杰,谷春云,杜显元,宋权威.污染场地卤代烃非生物自然衰减研究进展[J].环境科学研究,2021,34(3):742-754. |
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| 作者姓名： | 廖高明 马杰 谷春云 杜显元 宋权威 |
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| 作者单位： | 中国石油大学(北京)化学工程与环境学院,北京 102249;重质油国家重点实验室,北京 102249;油气污染防治北京市重点实验室,北京 102249;石油石化污染物控制与处理国家重点实验室,北京 102206;中国石油安全环保技术研究院有限公司,北京 102206 |
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| 基金项目： | 国家自然科学基金项目（No.21878332）；北京市科技新星计划（No.Z181100006218088）；中石油科技创新基金（No.2018D-5007-0607） |
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| 摘 要： | 传统的卤代烃自然衰减研究主要关注生物降解过程，然而近年有研究发现卤代烃可以被地层中的活性矿物还原降解.对天然活性矿物介导下卤代烃非生物自然衰减的研究进展总结显示，可以还原降解卤代烃的天然矿物主要包括铁硫矿物、铁氧矿物和含铁黏土矿物等，其中铁硫矿物在含水层中分布最为广泛.常见的反应机制包括还原消除、氢解、自由基加成、自由基偶联、脱卤化氢、水解，其中还原消除和氢解是其中最重要的两种反应机制，常见于卤代烷烃和卤代烯烃的非生物降解.卤代烃的非生物降解产物主要取决于还原降解途径和母体卤代烃.不同矿物对卤代烃的降解活性大致表现为马基诺矿?黄铁矿>黑云母>蛭石≈绿锈>磁铁矿≈蒙脱石.卤代烃的降解速率除受矿物种类影响外，还受到卤代烃种类、pH、硫化物浓度、共存金属离子、天然有机物、矿物形态等因素的影响.现有的研究已经确证活性矿物的还原降解是卤代烃自然衰减的重要机制，但该领域中仍然有一些重要知识点有待进一步研究.关于活性铁矿物Fe（Ⅱ）类型和反应能力之间的关系、还原卤代烃过程中Fe（Ⅱ）的结构变化以及结构态Fe（Ⅱ）向卤代烃的电子转移方式等仍然不清楚，建议进行更深入的研究；现有研究大都基于实验室小试装置，实际场地的研究不多，建议今后进一步探究实验室发现的规律是否符合场地中的实际情况；地下水位波动导致活性矿物间歇性暴露在溶解氧中，可能产生羟自由基（·OH）实现并导致卤代烃的氧化降解，这方面的研究目前尚存在不足，建议给予更多关注.
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| 关 键 词： | 污染场地 自然衰减 卤代烃 活性矿物 非生物降解 |
| 收稿时间： | 2020/6/24 0:00:00 |
| 修稿时间： | 2020/9/24 0:00:00 |
Research Progress on Abiotic Natural Attenuation of Halogenated Hydrocarbons at Contaminated Sites |
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| LIAO Gaoming,MA Jie,GU Chunyun,DU Xianyuan,SONG Quanwei.Research Progress on Abiotic Natural Attenuation of Halogenated Hydrocarbons at Contaminated Sites[J].Research of Environmental Sciences,2021,34(3):742-754. |
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| Authors: | LIAO Gaoming MA Jie GU Chunyun DU Xianyuan SONG Quanwei |
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| Affiliation: | 1.China University of Petroleum-Beijing, College of Chemical Engineering and Environment, Beijing 102249, China2.State Key Laboratory of Heavy Oil Processing, Beijing 102249, China3.Beijing Key Lab of Oil & Gas Pollution Control, Beijing 102249, China4.State Key Laboratory of Petroleum Pollution Control, Beijing 102206, China5.CNPC Research Institute of Safety and Environment Technology, Beijing 102206, China |
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| Abstract: | Traditional studies of natural attenuation of halogenated hydrocarbons mainly focus on biodegradation process. However, recent studies have found that halogenated hydrocarbons can be geochemically reduced by the reactive minerals in the subsurface environment. This process is called abiotic natural attenuation of halogenated hydrocarbons. This article reviews the latest research progress on the abiotic natural attenuation of halogenated hydrocarbons mediated by natural reactive minerals. The reactive minerals that can reduce halogenated hydrocarbons include iron-sulfur minerals, iron oxide minerals and iron-bearing clay minerals. Among them, iron-sulfur minerals are the most abundant mineral in aquifers. The reaction pathways include dichloroelimination, hydrogenolysis, radical addition, radical coupling, dehydrohalogenation, and hydrolysis. Dichloroelimination and hydrogenolysis are the most important reaction pathways, especially for halogenated alkanes and halogenated alkenes. The chemical composition of abiotic degradation products mainly depends on the reaction pathway and the parent halogenated hydrocarbons. The reaction rate of various halogenated hydrocarbons reported in the literatures are compiled and analysed. The analysis of reaction rate data suggests that the reactivity of different minerals generally follows the trend: mackinawite?pyrite > biotite > vermiculite≈green rust > magnetite≈montmorillonite. The reaction rate is also affected by factors such as the type of halogenated hydrocarbons, pH, sulfide concentration, coexisting metal ions, natural organic matter, and mineral morphology. Overall, current studies corroborate that reduction by reactive minerals is a key natural attenuation mechanism for halogenated hydrocarbons. However, there are still several critical knowledge gaps. It is still unclear about the relationship between the types of Fe(Ⅱ) in reactive minerals and their reactivity, the structural changes of Fe(Ⅱ) during the reduction of halogenated hydrocarbons, and the mechanisms of electron transfer from structural Fe(Ⅱ) to halogenated hydrocarbons. Current researches are mainly laboratory bench-scale studies while field studies are rare. Further field studies are necessary to confirm that the knowledge obtained through laboratory studies is consistent with field observations. Fluctuations in shallow water table would cause the reactive mineral exposure to dissolved oxygen. Reactions of the reactive minerals with oxygen generate hydroxyl radical (·OH) that can oxidize halogenated hydrocarbons. Further researches are needed in this area. |
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| Keywords: | contaminated site natural attenuation halogenated hydrocarbons reactive minerals abiotic degradation |
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