, 邢志林1,2, 杨旭1, 王尔玉11 重庆理工大学 化学化工学院，重庆 400050;
2 重庆大学 城市建设与环境工程学院，重庆 400045
收稿日期：2017-10-23;接收日期：2018-01-04 基金项目：国家自然科学基金(Nos. 41502328，51378522)，重庆市基础与前沿研究项目(No. cstc2015jcyjB0015)，重庆理工大学研究生创新基金(No. YCX2016236)资助
摘要：氯代脂肪烃(Chlorinated aliphatic hydrocarbons，CAHs)具有高毒性、高富集性、高环境残留的特点和致癌、致畸、致突变效应，对人体健康和生态环境造成了严重危害。CAHs降解是生物和非生物过程共同作用的结果，存在多种交互作用，明晰CAHs的生物与非生物共促降解机制对于强化CAHs污染场地修复具有重要意义。文中首先对CAHs降解方式进行了分类介绍，按照还原脱氯、好氧共代谢和直接氧化三种方式总结了影响CAHs降解的典型生物与非生物降解因子。从共促降解的角度出发，系统分析并提出了诱导降解机制和协同降解机制，并对基于共促机制强化CAHs降解的工程应用与存在的技术局限进行了综述和分析，最后对未来的发展方向进行了展望。
关键词：氯代脂肪烃 共促降解 诱导降解机制 协同降解机制
Advances in biotic and abiotic mutual promoting mechanism for chlorinated aliphatic hydrocarbons degradation
Liu Shuai1, Zhao Tiantao1,2
, Xing Zhilin1,2, Yang Xu1, Wang Eryu1 1 College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400050, China;
2 College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China
Received: October 23, 2017; Accepted: January 4, 2018
Supported by: National Natural Science Foundation of China (Nos. 41502328, 51378522), Fundamental and Advanced Research Projects of Chongqing (No. cstc2015jcyjB0015), Chongqing University of Technology Graduate Innovation Fund (No. YCX2016236)
Corresponding author:Tiantao Zhao. Tel/Fax: +86-23-62563225; E-mail: zhaott@cqut.edu.cn
Abstract: Chlorinated aliphatic hydrocarbons (CAHs) with characteristics of high toxicity, biological accumulation and recalcitrance to degradation as well as carcinogenicity, teratogenesis and mutagenicity, are seriously harmful to human health and ecological environment. CAHs degradation depends on biotic and abiotic responses that exist diversified interactive effects, so it is important to clarify the mechanism of CAHs degradation via biotic and abiotic mutual promoting to significantly enhance the CAHs-contaminated site restoration. In this work, a series of pathways for CAHs degradation was first introduced and summarized as three means on reductive dechlorination, aerobic cometabolism and direct oxidation, and biotic and abiotic typical factors affecting CAHs degradation were concluded from these. Then, mechanisms of induced degradation and synergistic degradation were indicated from the perspective of mutual promoting degradation both with biotic and abiotic responses, and furthermore, the application and technical limitations of CAHs degradation enhanced via biotic and abiotic mutual promoting were reviewed and analyzed. Finally, the development of CAHs degradation technology in future was prospected.
Key words: chlorinated aliphatic hydrocarbons mutual promoting degradation induced degradation mechanism synergistic degradation mechanism
氯代脂肪烃(Chlorinated aliphatic hydrocarbons，CAHs)是一类重要的有机溶剂，广泛应用于机械制造、电子元件清洗和化学化工等过程。由于大规模生产和不当使用，CAHs已成为世界各国工业化地区常见污染物。美国环保局曾对39个小城镇地下水供水水源进行检测，结果表明，在已处理和未经处理的地下水中都发现了11种CAHs，检出率最高的是三氯乙烯(TCE)和氯仿(CF)，分别为36%和31%[1]。德国Bitterfeld地区经过近百年的化学工业发展，土壤和地下水受到了CAHs的严重污染，涉及的土壤面积高达25 km2，约有2亿m3的地下水遭受污染[2]。我国“水中优先控制污染物”中前9种均为CAHs[3]。且CAHs均具有“三致” (致癌、致畸、致突变)效应或可疑“三致”效应，严重威胁人类健康[4]。因此，采取有效方式去除该类污染物已引起环保领域的广泛关注。
CAHs去除方式包括生物降解和非生物降解。生物降解可分为还原脱氯、好氧共代谢和直接氧化。还原脱氯降解是具有降解所有种类CAHs潜力的修复方式[5]，但还原脱氯降解以CAHs作为电子受体，需要合适的电子供体，研究表明丙酸盐、丁酸盐、乳酸盐、甲醇、乙醇、乙酸盐以及微生物发酵产生的H2是常见电子供体，还原脱氯降解强度会受Fe0等非生物降解因子的显著影响[6]。好氧共代谢降解是CAHs降解的另一重要方式，除全氯取代烃外，其他CAHs均可通过好氧共代谢降解，好氧共代谢降解可通过曝气和添加共代谢基质进行强化，好氧共代谢降解中的酶主要为单加氧酶和双加氧酶。直接氧化降解过程中微生物直接以CAHs作为碳源和能源进行生长，避免了因添加生长基质而引起的代谢副产物的产生[7]，具有显著优势，但目前只发现了一氯甲烷(CM)、二氯甲烷(DCM)和氯乙烯(VC)等低氯取代的CAHs能被微生物直接氧化[8]，因此如何通过其他方式使高氯取代物转化为低氯取代物是实现该方法的重要步骤。CAHs的非生物降解分为化学氧化和化学还原，化学氧化过程的非生物降解因子包括高锰酸钾和芬顿试剂等强氧化剂，可将CAHs氧化为无毒化合物；化学还原过程的非生物降解因子为以Fe0为典型代表的还原剂，可将CAHs还原为低氯取代烃，再完全脱氯[9]。CAHs污染场地环境复杂，生物与非生物降解因子共存，明晰生物与非生物降解共促机制对CAHs污染场地修复意义重大。
采用生物降解对CAHs污染场地进行修复经济环保，但速率低并常伴有副产物的累积。非生物降解几乎没有生物降解所形成的典型中间产物，如TCE生物降解过程产生的二氯乙烯(DCE)和VC[10]，但处理费用高，易产生二次污染。单一处理方式难以实现CAHs经济、高效去除，当前联合生物与非生物过程强化CAHs污染场地修复成为主要趋势。Peale等[11]联合生物与非生物降解，不到一年，实现了污染场地TCE浓度由11 000 μg/L下降到小于5 μg/L。生物与非生物降解间存在多种交互作用，充分认识其共促降解机制对高效处理CAHs污染有重要意义。然而，目前仅有对CAHs在生物降解[12-13]或非生物降解[14-15]单独作用下的总结，以及对于一种CAH如CF[8]、四氯化碳(CT)[16]、TCE等[17]生物降解机制的论述，对于生物与非生物共促降解机制的分析和总结还鲜有报道。据此，文中结合本课题组在甲烷氧化菌共代谢降解CAHs方面的研究进展，系统分析了生物与非生物共促降解机制，综述了基于共促降解机制联合生物与非生物过程强化CAHs降解所取得的进展，并简析了生物与非生物降解间存在的抑制作用，最后浅析了现有研究中存在的问题及未来的发展方向，以期为CAHs污染场的修复提供优化策略和理论指导。
1 CAHs的生物和非生物降解概述1.1 CAHs的生物降解好氧共代谢降解是在有氧条件下，微生物利用生长基质的同时合成加氧酶降解CAHs的过程。常见的酶为甲烷单加氧酶[18]，产生甲烷单加氧酶的甲烷氧化菌在自然界分布广泛，其中包括湿地、沼泽、农田、森林、城镇土壤、米稻田、地下水和垃圾填埋场等[19]。直接氧化降解是微生物在有氧条件下，把CAHs作为唯一碳源和能源实现代谢的过程。与好氧共代谢降解相比直接氧化降解不需引入生长基质，避免了由生长基质引起的代谢副产物的生成，有很大的潜在优势。一般而言，只有含氯较少的CAHs (含有一个或两个氯)可以由微生物用作电子供体直接代谢。还原脱氯降解是微生物在厌氧条件下，以CAHs或生长基质为碳源和能源，通过直接代谢或共代谢的方式降解CAHs的过程。对于CAHs的还原脱氯降解，最典型的是四氯乙烯(PCE)的还原脱氯降解，其完整降解途径如图 1所示。虽然PCE的还原脱氯降解最终产物是乙烯，但大量的菌属只能完成PCE到DCE的过程，截止目前，只发现特殊的脱卤拟球菌属Dehalococcoides spp.能够完成PCE到乙烯的还原脱氯降解过程[12]。然而，Dehalococcoides spp.对氧气非常敏感，且活性较低[10]，所以PCE到乙烯的还原脱氯降解过程转化率很低，导致了大量中间产物的累积。
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| 图 1 PCE的完整还原脱氯降解途径示意图[22] Figure 1 Completely reductive dechlorination degradation of PCE[22]. |
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11种典型CAHs在好氧共代谢、直接氧化和还原脱氯三种生物降解方式下的中间产物和最终产物如表 1所示。氯甲烷(CA)、1, 2-二氯乙烷(1, 2-DCA)、顺-1, 2-二氯乙烯(cis-DCE)等非全氯取代的CAHs在好氧、厌氧条件下均能被降解，目前只发现CM、DCM和VC等低氯取代烃能以直接氧化降解方式被微生物直接代谢。高氯取代的CAHs难以进行直接氧化降解，可进行好氧共代谢降解，如CF、CT、1, 1, 1-三氯乙烷(1, 1, 1-TCA)、TCE、PCE等。全氯取代的CAHs在好氧条件下难以被降解，易进行还原脱氯降解，如CT、PCE等。当前，已报道的常见CAHs生物降解因子(生物降解因子指能降解CAHs的微生物)如表 2所示。进行好氧共代谢降解的主要为假单胞菌属Pseudomonas、红球菌属Rhodococcus、甲基弯曲菌属Methylosinus、伯克氏菌属Burkholderia、埃希氏菌属Escherichia、劳尔氏菌属Ralstonia、亚硝化单胞菌属Nitrosomonas等7个属，其中最主要为Pseudomonas。这些微生物通过产生单加氧酶或双加氧酶，如甲烷单加氧酶、甲烷双加氧酶、氨单加氧酶、甲苯单加氧酶、甲苯双加氧酶、烯烃单加氧酶、丁烷单加氧酶等[18]，将CAHs催化降解。目前发现的可实现直接氧化降解的菌属较少，主要为不动杆菌属Acinetobacter、芽孢杆菌属Bacillus、无色杆菌属Achromobacter、克雷伯氏菌属Klebsiella、Pseudomonas等5个属，相关分子生物学过程的研究并不多见。能进行还原脱氯降解的主要为Dehalogenimonas、Dehalospirillum、Dehalobacter、地杆菌属Geobacter、肠杆菌属Enterobacter、Desulfitobacterium、Dehalococcoides等7个属，其中Dehalo-菌为主要脱卤微生物。Maymó-Gatell等[20]首次分离出能使PCE完全脱氯的菌株产乙烯脱卤拟球菌Dehalococcoides ethenogenes strain 195，其tceA基因表达产生的脱卤素酶能够介导VC脱氯。氯代乙烯的完全脱氯依赖于还原脱卤同源基因(包括pceA、tceA、vcrA和bvcA)的存在[21]，但酶活性与基因表达之间的关系尚未得到充分的认识。
表 1 典型CAHs在不同生物降解方式下的降解产物Table 1 Degradation products of typical CAHs under different biodegradation manners
| Types of CAHs | Aerobic cometabolism degradation | Direct oxidation degradation | Reductive dechlorination degradation | |||
| Intermediate products | Final products | Intermediate products | Final products | Intermediate products | Final products | |
| CM | Methanol[23] | CO2[23] | No report | CO2[23] | No report | CH4[8] |
| DCM | CO, formaldehyde[24] | CO2[24] | No report | CO2[25] | CM[8] | CH4[8] |
| CF | Trichloromethanol, dichloroformaldehyde[26], formic acid[27] | CO2[26] | No report | No report | DCM, CM[8] | CH4[8] |
| CT | No report | No report | No report | No report | CF, DCM, CM[16] | CH4[16] |
| CA | Ethanol, acetic acid [28] | CO2[28] | No report | CO2[28] | No report | Ethane[28] |
| 1, 2-DCA | 2-Chloroacetaldehyde, 2-chloroethanol, 2-Chloroacetic acid, glycolic acid[29] | CO2[29] | No report | CO2[28] | CA, VC[30] | Ethylene[30], ethane[28] |
| 1, 1, 1-TCA | 2, 2, 2-Trichloroethanol[31] | CO2[29] | No report | No report | 1, 1-DCA, CA[28], 1, 1-DCE, VC[32] | Ethane[28] |
| VC | No report | CO2[10] | Epoxy vinyl chloride[10] | CO2[10] | No report | Ethylene[10] |
| cis-DCE | No report | CO2[10] | No report | CO2[10] | VC[10] | Ethylene[10] |
| TCE | Epoxy trichlorethylene[26], trichloroacetaldehyde[33], dichloroacetic acid, glyoxylic acid, formic acid[18], trichloroacetic acid, trichloromethane[33] | CO2[10] | No report | No report | cis-DCE, VC[10] | Ethylene[10] |
| PCE | No report | No report | No report | No report | TCE, cis-DCE, VC[10] | Ethylene[10] |
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表 2 常见的生物降解因子Table 2 Common biotic degradation factors
| Types of biodegradation | Biotic degradation factors (microorganisms) | References |
| Aerobic cometabolism degradation | Rhodococcus aetherovorans BCP1 | [34] |
| Pseudomonas cepacia G4 | [35] | |
| Methylosinus trichosporium OB3b | [36] | |
| Pseudomonas putida F1 | [37] | |
| Burkholderia cepacia G4 | [38] | |
| Recombinant Escherichia coli | [33] | |
| Pseudmonas mendocina KR1 | [36] | |
| Pseudomonas putida W619 | [39] | |
| Ralstonia pickettii PKO1 | [40] | |
| Nitrosomonas europaea | [41] | |
| Direct oxidation degradation | Acinetobacter species | [42] |
| Bacillus subtilis | [42] | |
| Bacillus cereus | [42] | |
| Achromobacter xylosoxidans | [42] | |
| Klebsiella | [42] | |
| Pseudomonas aeruginosa | [42] | |
| Reductive dechlorination degradation | Dehalogenimonas lykanthroporepellens | [43] |
| Dehalospirillum multivorans | [44] | |
| Dehalobacter restrictus | [45] | |
| Geobacter lovleyi | [46] | |
| Enterobacter agglomerans | [47] | |
| Desulfitobacterium sp. strain PCE1 | [48] | |
| Dehalococcoides ethenogenes strain 195 | [20] |
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1.2 CAHs的非生物降解非生物降解是CAHs去除的另一重要途径，研究表明大多数环境均存在CAHs的非生物降解因子[14]，已报道的可实现CAHs非生物降解的因子如表 3所示。根据氧化还原特性非生物降解因子可分为还原剂和氧化剂，还原剂主要包括Fe0、Zn0和多种天然铁矿物。Ferrey等[49]研究了一个磁铁矿(Fe3O4)丰富的地下水污染源，污染物包括cis-DCE和1, 1-DCE。在实验室中测定的cis-DCE的一级反应速率常数为113.15–835.85 d–1，1, 1-DCE为500.05 d–1。高压灭菌的土壤与环境土壤具有相同的降解速率，表明脱氯活性是非生物的。多项研究[50-51]表明FeS能有效脱除多种CAHs (包括PCE、TCE、CT等)中的氯。Lee和Batchelor[52]发现PCE、DCE和VC与黄铁矿(FeS2)反应具有良好的脱氯速率。现有研究最多的CAHs的氧化剂为高锰酸钾、芬顿试剂和过硫酸盐。
表 3 常见的非生物降解因子Table 3 Common abiotic degradation factors
| Abiotic degradation factors | Chemical formula | Redox properties | References |
| Zero-valent iron | Fe0 | Reducing agent | [53] |
| Zero-valent zinc | Zn0 | Reducing agent | [54] |
| Green rust | [Fe6–xⅡFexⅢ(OH)12]x+[(A)x/nyH2O]x?, A represent anion, common SO42– or Cl– | Reducing agent | [55] |
| Mackinawite | FeS | Reducing agent | [50] |
| Magnetite | Fe3O4 | Reducing agent | [49] |
| Pyrite | FeS2 | Reducing agent | [52] |
| Vivianite | Fe3(PO4)2·(H2O)8 | Reducing agent | [56] |
| Potassium permanganate | KMnO4 | Oxidizing agent | [57] |
| Fenton’s reagent | Fe2+, H2O2 | Oxidizing agent | [58] |
| Persulfate | Na2S2O8 | Oxidizing agent | [59] |
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CAHs的非生物降解反应机理相当复杂并伴有多种产物产生，Orth和Gillham[9]研究TCE与Fe0的反应发现乙烯和乙烷占原始当量TCE质量的80%以上；生物降解形成的典型中间产物DCE和VC仅占原始TCE质量的3%；还发现其他副产物，包括烃类(C1–C4)，如甲烷、丙烯、丙烷、1-丁烯和丁烷。Gillham和Hanesin[53]通过室内批次实验发现，Fe0能与12种CAHs发生反应，以半衰期衡量所得到的反应速率大小依次为：六氯乙烷 > CT > 1, 1, l, 2-四氯乙烷 > 1, 1, 2, 2-四氯乙烷 > 1, 1, 1-TCA > PCE > TCE > CF > 1, 1-DCE > VC > cis-DCE > 反-1, 2-DCE。可知CAHs的非生物降解速率受CAHs性质影响显著，包括氯取代数目和位置。实际场地修复中，非生物修复过程往往花费高，易产生二次污染物，结合生物降解是未来的发展方向。
2 CAHs生物与非生物的共促降解机制环境中生物降解因子和非生物降解因子往往同时存在，综合分析了大量文献，发现环境中生物与非生物过程主要通过两种机制促进CAHs降解，分别归纳为诱导降解机制和协同降解机制。
2.1 诱导降解机制诱导降解机制指在微生物诱导下形成了可用于CAHs降解的还原矿物，如FeS、Fe3O4等。FeS可作为还原剂降解CAHs，其作用类似于Fe0。硫酸盐还原菌(Sulfate-reducing bacteria，SRB)具有显著改变环境矿物组成的能力，可诱导FeS矿物快速形成。梁成浩等[60]研究表明，SRB代谢产物S2–与Fe2+反应生成FeS，SRB能不断提供H2S以维持FeS的电化学活性。Fe3O4是自然界中广泛存在的一种矿物，并可作为还原剂用于CAHs的降解，在有氧和厌氧条件下Fe3O4均可在相关微生物的作用下产生。Blakemore等[61]研究了水螺菌Aquaspirillum magnetotacticum作用下Fe3O4的产率与氧气、氮源的关系，最佳细胞磁性(即Fe3O4最大产率)发生在微有氧条件下，与氮源无关，并推论其他种类趋磁细菌形成Fe3O4也可能需要氧。Lovley等[62]在河口沉积物中分离得到一种微生物GS-15能在厌氧条件下产生大量超细颗粒Fe3O4，GS-15不是趋磁性的，而是将无定形Fe2O3还原为胞外Fe3O4的异化还原细菌，微生物在厌氧条件下也能产生Fe3O4。
通过诱导降解机制促进CAHs降解的过程如图 2所示。CAHs污染场地中SRB、趋磁细菌或异化还原细菌的存在将有助于CAHs的修复，因此在无CAHs直接代谢微生物的污染场地中，也可通过外源添加该类诱导微生物实现CAHs的去除。
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| 图 2 CAHs的诱导降解机制示意图 Figure 2 The schematic of CAHs degradation via induced mechanism. |
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2.2 协同降解机制协同降解机制促进CAHs降解的过程如图 3所示。与诱导降解机制通过微生物诱导产生非生物降解因子作用于CAHs不同，协同降解机制通过生物降解因子和非生物降解因子(主要为Fe0)共同作用于CAHs实现联合降解。利用该机制已开发了强化CAHs污染场地修复的药剂，其中一种药剂EHC?由缓释碳源、Fe0颗粒和营养物质组成。缓释碳源和营养物质可作为CAHs降解微生物的生长基质，促进CAHs的生物降解。Fe0颗粒可非生物降解CAHs，避免了生物降解过程典型中间产物的产生，如TCE生物降解过程产生的DCE和VC (DCE和VC的毒性更强)[10]，减少了生物降解过程中间产物对微生物的毒副作用，促进了CAHs的完全降解。缓释碳源可在厌氧条件下发酵产生有机酸，有机酸可消耗Fe0与CAHs反应过程中产生并累积于Fe0表面的OH–，从而加速Fe0表面进行的脱氯反应。从而更多的反应在Fe0表面进行。EHC?通过多种协同作用，把物理、化学和生物过程结合起来创造了一个还原性很强(氧化还原电位 < ?550 mV)的环境，从而强化CAHs的快速和完全脱氯[63]。另一种由表面活性剂、Fe0颗粒、植物油和水组成的乳化零价铁[64] (Emulsified zero-valent iron，EZVI)也已被报道，其照片及原理如图 4所示。EZVI能有效降解CAHs是由于：1)乳液颗粒的外部油膜具有类似于CAHs的疏水性质，所以乳液与CAHs可混溶，增加了接触面积；2) Fe0的非生物降解；3) EZVI乳液中油和表面活性剂的存在增强了生物降解。
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| 图 3 CAHs的协同降解机制示意图 Figure 3 The schematic of CAHs degradation via synergistic mechanism. |
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| 图 4 EZVI的照片及原理图[64] Figure 4 The schematic and photograph of EZVI[64]. |
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协同降解机制的另一方式是非生物降解因子产生电子供体，用于强化CAHs的还原脱氯降解。Bouwer和Mccarty[65]研究发现，产甲烷菌能够通过氢解或水解作用来脱除CAHs中的氯。Novak等[66]在研究产甲烷菌时，发现在其富集培养物中加入Fe0后，CT、CF的降解程度和和降解速率明显增强，其原因如下：1) Fe0本身与CAHs的反应；2)在Fe0到Fe2+的腐蚀过程中产生H2，H2可作为电子供体增强产甲烷菌的活性。
3 基于共促降解强化CAHs污染控制的应用CAHs实际污染场地的修复往往非常复杂，总结了联合生物与非生物过程强化CAHs降解的研究，并结合共促降解机制进行了分析。如表 4所示，Kennedy开发了生物地球化学还原脱氯(Biogeochemical reductive dechlorination，BiRD)技术[67]，其原理是利用诱导降解机制强化CAHs降解。BiRD技术可以分为3个阶段：生物硫酸盐还原阶段、地球化学矿物形成阶段和脱氯阶段。生物硫酸盐还原阶段只需添加含有足够SO42–的可溶性不稳定有机物(不需要添加SRB，因为SRB在大多数环境中普遍存在)，然后SRB氧化有机物产生硫化氢(H2S)。地球化学阶段是FeS的形成阶段，H2S可与自然界中大量存在的Fe (Ⅲ)和Fe (Ⅱ)氧化物/氢氧化物(如针铁矿、α-FeOOH)反应形成FeS，随后FeS可以转化为FeS2，最后自发进行脱氯反应。式(1)–(5)为反应过程方程式。
 | (1) |
 | (2) |
 | (3) |
 | (4) |
 | (5) |
| Technology or reagent | Abiotic factors | Microorganism | Types of degradation mechanism | Types of CAHs | Result | References |
| BiRD | FeS (SRB induced production) | SRB | Induced | PCE, TCE, DCE | Less than a year, PCE, TCE and DCE degradation rate of up to 95% or more. | [68] |
| NTR | Fe3O4 (Geobacter metallireducens induced production) | Geobacter metallireducens | Induced | CT | The mineral-mediated (abiotic) reaction was estimated to be 60–260-fold faster than the biotic reaction throughout the incubation period. | [79] |
| NTR | Carboxymethylcellulose (stabilizer), nanoscale Fe0 | Dehalococcoides spp. | Synergistic | PCE, TCE, CF | The abundance of Dehalococcoides spp. immediately increased by 1 order of magnitude, distinctly higher CAHs degradation occurred when compared to control wells. | [80] |
| EHC? | Controlled-release carbon, Fe0, nutrients | KB-1? (Dehalococcoides ethenogenes) | Synergistic | TCE | Less than a year, TCE concentration decreased from 11 000 μg/L to less than 5 μg/ L. | [11] |
| EZVI | Surfactant, Fe0, vegetable oil, water | Indigenous microorganism | Synergistic | TCE | Significant reductions in TCE soil concentrations ( > 80%) were observed at four of the six soil sampling locations within 90 days of EZVI injection. Significant reductions in TCE groundwater concentrations (57% to 100%) were observed at all depths targeted with EZVI. | [64] |
| NTR | Fe0 | Dehalobacter | Synergistic | CF | CF transformation and DCM formation was up to 8-fold faster and 14 times higher, respectively, when a Dehalobacter-containing enrichment culture was combined with Fe0 compared with Fe0 alone. | [81] |
| NTR | Fe0, H2 | Isolated from the landfill of Dover Air Force Base | Synergistic | TCE | Rapid formation and degradation of cis-DCE was observed in reactors containing cells plus Fe0 or H2 as a bulk reducing agent. High levels of VC were formed and very similar profiles were obtained in the Fe0 plus cell and H2 plus cell reactors, but not in Fe0-only reactors. | [82] |
| NTR | Fe0 | Methanosarcina barkeri, Methanosarcina thermophila, Methanosaeta concillii | Synergistic | CT, CF | The rate and extent of carbon CT and CF dechlorination were enhanced when a methanogenic enrichment culture and Fe0 were incubated together. | [66] |
| Notes: NTR represent non-technology or reagent. | ||||||
表选项
Kennedy等用BiRD在一个氯代烯烃污染场地进行了现场试验，结果表明，修复在注射后几周开始，不到一年PCE、TCE和DCE降解率高达95%以上[68]。
Peale等用EHC?和KB-1? (一种厌氧菌剂，包括Dehalococcoides ethenogenes)成功修复了一个TCE污染场地，不到一年TCE浓度由11 000 μg/L下降到小于5 μg/L[11]。Quinn等用EZVI处理受TCE污染的土壤和地下水，结果表明，90 d内，6个土壤取样点中4个TCE浓度显著降低( > 80%)，地下水中所有深度TCE浓度均显著下降(57%–100%)[64]。Aulenta等[71]在产甲烷菌富集培养物中加入Fe0，发现CT和CF脱氯速率和程度明显增强，其中巴氏甲烷八叠球菌Methanosarcina barkeri单独作用时CT和CF的一阶速率常数分别为2.13±0.30和0.39±0.14，Fe0单独作用时CT和CF的一阶速率常数分别为4.74±0.15和0.21±0.13，共同作用时CT和CF的一阶速率常数分别为9.84±1.09和0.76±0.43。SRB诱导产生的FeS、硫还原泥土杆菌Geobacter metallireducens诱导产生的Fe3O4可强化CAHs降解，Dehalococcoides spp.、Dehalococcoides ethenogenes、Dehalobacter、Methanosarcina barkeri、甲烷八叠球菌Methanosarcina thermophila、甲烷丝菌Methanosaeta concilliis等微生物能与非生物因子产生共促降解机制(表 4)。本课题组在生活垃圾填埋场覆盖土降解CAHs方面开展了大量研究，发现除甲烷外还有多种底物和多种属微生物参与了CAHs生物降解，铜离子等非生物因子会显著影响生物降解CAHs的活性[69]。这些研究表明联合生物与非生物降解可显著提高对CAHs的降解能力，在未来污染物的原位修复中具有重大的应用潜力。
除了共促降解机制外，CAHs联合降解还可能存在抑制作用(图 5)。还原脱氯降解可通过提供电子供体来强化脱氯微生物[70]，但微生物也可以使用其他的末端电子受体[70-71]。根据热力学评价，末端电子受体顺序为O2 > 硝酸盐 > Mn (Ⅳ) > Fe(Ⅲ) > CAHs > 硫酸盐 > CO2/乙酸盐[46, 72-73]。O2和硝酸盐存在时，CAHs的还原脱氯降解被完全抑制，Fe(Ⅲ)还原和硫酸盐还原常与脱氯同时发生，因此这些末端电子受体可能竞争电子供体[71, 74-75]。Paul等[76]研究表明，不良结晶的Fe(Ⅲ)会抑制TCE的还原脱氯降解，而结晶良好的Fe(Ⅲ)如针铁矿或赤铁矿没有抑制效果。如式(5)所示，在CAHs的非生物降解过程会产生Fe(Ⅲ)，BiRD技术中需要加入硫酸盐，同时自然界中也存在许多Fe(Ⅲ)和硫酸盐，从而竞争可用电子供体，进而抑制CAHs生物降解。化学氧化常用于CAHs污染场地，但氧化剂会抑制微生物活性并显著影响其群落结构[77]。相比于氧化CAHs，化学氧化可能先氧化其他有机物，从而导致土著微生物缺乏碳源[78]，进而抑制CAHs的生物降解。在实际污染场地的修复中，应利用生物与非生物的共促降解机制，并尽量避免抑制作用的出现。
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| 图 5 CAHs的抑制作用示意图 Figure 5 The schematic of the inhibition of CAHs degradation. |
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4 总结与展望本文简介了CAHs的生物降解和非生物降解，系统分析并提出了CAHs生物与非生物的共促降解机制，包括诱导降解机制和协同降解机制，综述了基于共促降解强化CAHs污染控制的应用，并简析了CAHs生物与非生物降解可能存在的抑制作用。目前，对于CAHs降解的研究基本只限于生物或非生物单独作用时CAHs的降解机理、降解途径、降解情况等，且其中多数只研究了一种CAH，而污染场地几乎都是多种污染物共同作用下的污染。此外，国内大多数研究都是在实验室进行的模拟实验，在实际污染场地进行的原位研究并不多见。因此，未来研究中需要利用CAHs生物与非生物的共促降解机制来更加关注以下几个方面：1)联合生物与非生物过程强化CAHs降解，如开发与EHC?和EZVI类似的能与生物降解协同作用的新药剂，鉴定能与非生物因子产生共促降解机制的相关微生物，明晰共促降解机理等；2) CAHs的生物降解、非生物降解与其他污染物降解的相互作用；3)多种污染物共同作用下的降解机理、降解途径、降解情况等；4)实际污染场地的降解情况，从而指导污染场地的修复。
附：缩略词索引
BiRD：生物地球化学还原脱氯，Biogeochemical reductive dechlorination
CA：氯乙烷，Chloroethane
CAHs：氯代脂肪烃，Chlorinated aliphatic hydrocarbons
CF：三氯甲烷，Chloroform
cis-DCE：顺-1, 2-二氯乙烯，cis-1, 2-dichloroethene
CM：氯甲烷，Chloromethane
CT：四氯化碳，Carbon tetrachloride
DCA：二氯乙烷，Dichloroethane
DCE：二氯乙烯，Dichloroethene
DCM：二氯甲烷，Dichloromethane
EZVI：乳化零价铁，Emulsified zero-valent iron
KB-1?：一种厌氧菌剂，Dehalococcoides ethenogenes
NTR：非技术或药剂，Non-technology or reagents
PCE：四氯乙烯，Perchloroethylene
SRB：硫酸盐还原菌，Sulfate-reducing bacteria
TCA：三氯乙烷，Trichloroethane
TCE：三氯乙烯，Trichloroethylene
VC：氯乙烯，Vinyl chloride
参考文献
| [1] | Lu Q, Li H, Lin KF, et al. Investigation of chlorinated hydrocarbons in groundwater from a typical contaminated site in Pudong District, Shanghai.Acta Sci Circum, 2016, 36(5): 1730–1737.(in Chinese). 陆强, 李辉, 林匡飞, 等. 上海浦东某氯代烃场地地下水污染现状调查.环境科学学报, 2016, 36(5): 1730-1737. |
| [2] | Heidrich S, Wei H, Kaschl A. Attenuation reactions in a multiple contaminated aquifer in Bitterfeld (Germany).Environ Pollut, 2004, 129(2): 277–288.DOI: 10.1016/j.envpol.2003.10.029 |
| [3] | Wang Z, Shi JS, Zhang ZJ, et al. Groundwater contamination risk assessment: A Chinese list of preferred controlled organic pollutants in water.Water Resour Prot, 2009, 25(1): 90–94.(in Chinese). 王昭, 石建省, 张兆吉, 等. 我国"水中优先控制有机物"对地下水污染的预警性研究.水资源保护, 2009, 25(1): 90-94. |
| [4] | Harwell JH, Sabatini DA, Knox RC. Surfactants for ground water remediation.Colloid Surface A, 1999, 151(1/2): 255–268. |
| [5] | Fiedler L. Engineered approaches to in situ bioremediation of chlorinated solvents: fundamentals and field applications.Eur Psychiat, 2000, 29(2): 101–105. |
| [6] | Aulenta F, Majone M, Tandoi V. Enhanced anaerobic bioremediation of chlorinated solvents: environmental factors influencing microbial activity and their relevance under field conditions.J Chem Technol Biot, 2006, 81(9): 1463–1474.DOI: 10.1002/(ISSN)1097-4660 |
| [7] | Mattes TE, Alexander AK, Coleman NV. Aerobic biodegradation of the chloroethenes: pathways, enzymes, ecology, and evolution.FEMS Microbiol Rev, 2010, 34(4): 445–475.DOI: 10.1111/j.1574-6976.2010.00210.x |
| [8] | Cappelletti M, Frascari D, Zannoni D, et al. Microbial degradation of chloroform.Appl Microbiol Biot, 2012, 96(6): 1395–1409.DOI: 10.1007/s00253-012-4494-1 |
| [9] | Orth WS, Gillham RW. Dechlorination of trichloroethene in aqueous solution using Fe0.Environ Sci Technol, 1996, 30(1): 66–71.DOI: 10.1021/es950053u |
| [10] | Tiehm A, Schmidt KR. Sequential anaerobic/aerobic biodegradation of chloroethenes—aspects of field application.Curr Opin Biotechnol, 2011, 22(3): 415–421.DOI: 10.1016/j.copbio.2011.02.003 |
| [11] | Peale JGD, Mueller J, Molin J. Successful ISCR-enhanced bioremediation of a TCE DNAPL source utilizing EHC? and KB-1?.Remediat J, 2010, 20(3): 63–81.DOI: 10.1002/rem.v20:3 |
| [12] | Frascari D, Zanaroli G, Danko AS. In situ aerobic cometabolism of chlorinated solvents: a review.J Hazard Mater, 2015, 283: 382–399.DOI: 10.1016/j.jhazmat.2014.09.041 |
| [13] | Koenig J, Lee M, Manefield M. Aliphatic organochlorine degradation in subsurface environments.Rev Environ Sci Bio/Technol, 2015, 14(1): 49–71.DOI: 10.1007/s11157-014-9345-3 |
| [14] | He YT, Wilson JT, Su C, et al. Review of abiotic degradation of chlorinated solvents by reactive iron minerals in aquifers.Ground Water Monit Remediat, 2015, 35(3): 57–75.DOI: 10.1111/gwmr.12111 |
| [15] | Tobiszewski M, Namie?nik J. Abiotic degradation of chlorinated ethanes and ethenes in water.Environ Sci Pollut Res, 2012, 19(6): 1994–2006.DOI: 10.1007/s11356-012-0764-9 |
| [16] | Penny C, Vuilleumier S, Bringel F. Microbial degradation of tetrachloromethane: mechanisms and perspectives for bioremediation.FEMS Microbiol Ecol, 2010, 74(2): 257–275.DOI: 10.1111/fem.2010.74.issue-2 |
| [17] | Pant P, Pant S. A review: Advances in microbial remediation of trichloroethylene (TCE).J Environ Sci, 2010, 22(1): 116–126.DOI: 10.1016/S1001-0742(09)60082-6 |
| [18] | Suttinun O, Luepromchai E, Müller R. Cometabolism of trichloroethylene: concepts, limitations and available strategies for sustained biodegradation.Rev Environ Sci Bio/Technol, 2013, 12(1): 99–114.DOI: 10.1007/s11157-012-9291-x |
| [19] | Zhao TT, Xing ZL, Zhang LJ. Research progress and discovery process of facultative methanotrophs-a review.Acta Microbiol Sin, 2013, 53(8): 781–789.(in Chinese). 赵天涛, 邢志林, 张丽杰. 兼性甲烷氧化菌的发现历程.微生物学报, 2013, 53(8): 781-789. |
| [20] | Maymó-Gatell X, Chien YT, Gossett JM, et al. Isolation of a bacterium that reductively dechlorinates tetrachloroethene to ethene.Science, 1997, 276(5318): 1568–1571.DOI: 10.1126/science.276.5318.1568 |
| [21] | Tang SQ, Chan WWM, Fletcher KE, et al. Functional characterization of reductive dehalogenases by using blue native polyacrylamide gel electrophoresis.Appl Environ Microbiol, 2013, 79(3): 974–981.DOI: 10.1128/AEM.01873-12 |
| [22] | Distefano TD, Gossett JM, Zinder SH. Hydrogen as an electron donor for dechlorination of tetrachloroethene by an anaerobic mixed culture.Appl Environ Microbiol, 1992, 58(11): 3622–3629. |
| [23] | Mcdonald IR, Warner KL, Mcanulla C, et al. A review of bacterial methyl halide degradation: biochemistry, genetics and molecular ecology.Environ Microbiol, 2002, 4(4): 193–203.DOI: 10.1046/j.1462-2920.2002.00290.x |
| [24] | Trotsenko YA, Torgonskaya ML. The aerobic degradation of dichloromethane: structural-functional aspects (a review).Appl Biochem Microbiol, 2009, 45(3): 233–247.DOI: 10.1134/S0003683809030016 |
| [25] | Doronina NV, Trotsenko YA, Tourova TP, et al. Albibacter methylovorans gen. nov., sp. nov., a novel aerobic, facultatively autotrophic and methylotrophic bacterium that utilizes dichloromethane.Int J Syst Evol Micr, 2001, 51(3): 1051–1058.DOI: 10.1099/00207713-51-3-1051 |
| [26] | Xing ZL, Zhang LJ, Zhao TT. Advances in degradation of chlorinated hydrocarbons by obligate and facultative methanotrophs.Chin J Biotech, 2014, 30(4): 531–544.(in Chinese). 邢志林, 张丽杰, 赵天涛. 专一营养与兼性甲烷氧化菌降解氯代烃的研究现状、动力学分析及展望.生物工程学报, 2014, 30(4): 531-544. |
| [27] | Bhatt P, Kumar MS, Mudliar S, et al. Biodegradation of chlorinated compounds—a review.Crit Rev Environ Sci Technol, 2007, 37(2): 165–198.DOI: 10.1080/10643380600776130 |
| [28] | Scheutz C, Durant ND, Hansen MH, et al. Natural and enhanced anaerobic degradation of 1, 1, 1-trichloroethane and its degradation products in the subsurface—a critical review.Water Res, 2011, 45(9): 2701–2723.DOI: 10.1016/j.watres.2011.02.027 |
| [29] | Gwinn MR, Johns DO, Bateson TF, et al. A review of the genotoxicity of 1, 2-dichloroethane (EDC).Mutat Res, 2011, 727(1-2): 42–53.DOI: 10.1016/j.mrrev.2011.01.001 |
| [30] | De Wildeman S, Verstraete W. The quest for microbial reductive dechlorination of C2 to C4 chloroalkanes is warranted.Appl Microbiol Biot, 2003, 61(2): 94–102.DOI: 10.1007/s00253-002-1174-6 |
| [31] | Yagi O, Hashimoto A, Iwasaki K, et al. Aerobic degradation of 1, 1, 1-trichloroethane by Mycobacterium spp. isolated from soil.Appl Environ Microb, 1999, 65(10): 4693–4696. |
| [32] | Palau J, Jamin P, Badin A, et al. Use of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1, 1, 1-trichloroethane in groundwater.Water Res, 2016, 92(9): 235–243. |
| [33] | Winter RB, Yen KM, Ensley BD. Efficient degradation of trichloroethylene by a recombinant Escherichia coli.Nat Biotechnol, 1989, 7(3): 282–285.DOI: 10.1038/nbt0389-282 |
| [34] | Ciavarelli R, Cappelletti M, Fedi S, et al. Chloroform aerobic cometabolism by butane-growing Rhodococcus aetherovorans BCP1 in continuous-flow biofilm reactors.Bioproc Biosyst Eng, 2012, 35(5): 667–681.DOI: 10.1007/s00449-011-0647-3 |
| [35] | Folsom BR, Chapman PJ, Pritchard PH. Phenol and trichloroethylene degradation by Pseudomonas cepacia G4: Kinetics and interactions between substrates.Appl Environ Microb, 1990, 56(5): 1279–1285. |
| [36] | Sun AK, Wood TK. Trichloroethylene degradation and mineralization by Pseudomonads and Methylosinus trichosporium OB3b.Appl Microbiol Biotechnol, 1996, 45(1-2): 248–256.DOI: 10.1007/s002530050679 |
| [37] | Lau PCK, Bergeron H, Labbé D, et al. Sequence and expression of the todGIH genes involved in the last three steps of toluene degradation by Pseudomonas putida F1.Gene, 1994, 146(1): 7–13.DOI: 10.1016/0378-1119(94)90827-3 |
| [38] | Radway JC, Santo-Domingo JW, Hazen TC, et al. Evaluation of biodegradation potential of foam embedded Burkholderia cepacia G4.Biotechnol Lett, 1998, 20(7): 663–666.DOI: 10.1023/A:1005366406453 |
| [39] | Weyens N, Truyens S, Dupae J, et al. Potential of the TCE-degrading endophyte Pseudomonas putida W619-TCE to improve plant growth and reduce TCE phytotoxicity and evapotranspiration in poplar cuttings.Environ Pollut, 2010, 158(9): 2915–2919.DOI: 10.1016/j.envpol.2010.06.004 |
| [40] | Park J, Kukor JJ, Abriola LM. Characterization of the adaptive response to trichloroethylene-mediated stresses in Ralstonia pickettii PKO1.Appl Environ Microbiol, 2002, 68(11): 5231–5240.DOI: 10.1128/AEM.68.11.5231-5240.2002 |
| [41] | Arciero D, Vannelli T, Logan M, et al. Degradation of trichloroethylene by the ammonia-oxidizing bacterium Nitrosomonas europaea.Biochem Bioph Res Commun, 1989, 159(2): 640–643.DOI: 10.1016/0006-291X(89)90042-9 |
| [42] | Olaniran AO, Pillay D, Pillay B. Aerobic biodegradation of dichloroethenes by indigenous bacteria isolated from contaminated sites in Africa.Chemosphere, 2008, 73(1): 24–29.DOI: 10.1016/j.chemosphere.2008.06.003 |
| [43] | Moe WM, Yan J, Nobre MF, et al. Dehalogenimonas lykanthroporepellens gen. nov., sp. nov., a reductively dehalogenating bacterium isolated from chlorinated solvent-contaminated groundwater.Int J Syst Evolut Microbiol, 2009, 59(11): 2692–2697.DOI: 10.1099/ijs.0.011502-0 |
| [44] | Neumann A, Scholz-Muramatsu H, Diekert G. Tetrachloroethene metabolism of Dehalospirillum multivorans.Arch Microbiol, 1994, 162(4): 295–301.DOI: 10.1007/BF00301854 |
| [45] | Holliger C, Hahn D, Harmsen H, et al. Dehalobacter restrictus gen. nov. and sp. nov., a strictly anaerobic bacterium that reductively dechlorinates tetra-and trichloroethene in an anaerobic respiration.Arch Microbiol, 1998, 169(4): 313–321.DOI: 10.1007/s002030050577 |
| [46] | Sung Y, Fletcher KE, Ritalahti KM, et al. Geobacter lovleyi sp. nov. strain SZ, a novel metal-reducing and tetrachloroethene-dechlorinating bacterium.Appl Environ Microb, 2006, 72(4): 2775–2782.DOI: 10.1128/AEM.72.4.2775-2782.2006 |
| [47] | Sharma PK, Mccarty PL. Isolation and characterization of facultatively aerobic bacterium that reductively dehalogenates tetrachloroerhene to cis-1, 2-dichloroethene.Appl Environ Microbiol, 1996, 62(3): 761–765. |
| [48] | Gerritse J, Renard V, Gomes TMP, et al. Desulfitobacterium sp. strain PCE1, an anaerobic bacterium that can grow by reductive dechlorination of tetrachloroethene or ortho-chlorinated phenols.Arch Microbiol, 1996, 165(2): 132–140.DOI: 10.1007/s002030050308 |
| [49] | Ferrey ML, Wilkin RT, Ford RG, et al. Nonbiological removal of cis-dichloroethylene and 1, 1-dichloroethylene in aquifer sediment containing magnetite.Environ Sci Technol, 2004, 38(6): 1746–1752.DOI: 10.1021/es0305609 |
| [50] | Gander JW, Parkin GF, Scherer MM. Kinetics of 1, 1, 1-trichloroethane transformation by iron sulfide and a methanogenic consortium.Environ Sci Technol, 2002, 36(21): 4540–4546.DOI: 10.1021/es025628j |
| [51] | Butler EC, Hayes KF. Kinetics of the transformation of trichloroethylene and tetrachloroethylene by iron sulfide.Environ Sci Technol, 1999, 33(12): 2021–2027.DOI: 10.1021/es9809455 |
| [52] | Lee W, Batchelor B. Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing soil minerals. 2. Green Rust.Environ Sci Technol, 2002, 36(24): 5348–5354.DOI: 10.1021/es0258374 |
| [53] | Gillham RW, O'Hannesin SF. Enhanced degradation of halogenated aliphatics by zero-valent iron.Ground Water, 1994, 32(6): 958–967.DOI: 10.1111/gwat.1994.32.issue-6 |
| [54] | Cheng SF, Wu SC. The enhancement methods for the degradation of TCE by zero-valent metals.Chemosphere, 2000, 41(8): 1263–1270.DOI: 10.1016/S0045-6535(99)00530-5 |
| [55] | Ayala-Luis KB, Cooper NG A, Koch CB, et al. Efficient dechlorination of carbon tetrachloride by hydrophobic green rust intercalated with dodecanoate anions.Environ Sci Technol, 2012, 46(6): 3390–3397.DOI: 10.1021/es204368u |
| [56] | Bae S, Lee W. Enhanced reductive degradation of carbon tetrachloride by biogenic vivianite and Fe(Ⅱ).Geochim Cosmochim Acta, 2012, 85: 170–186.DOI: 10.1016/j.gca.2012.02.023 |
| [57] | Kim K, Gurol MD. Reaction of nonaqueous phase TCE with permanganate.Environ Sci Technol, 2010, 39(23): 9303–9308. |
| [58] | Qiang ZM, Ben WW, Huang CP. Fenton process for degradation of selected chlorinated aliphatic hydrocarbons exemplified by trichloroethylene, 1, 1-dichloroethylene and chloroform.Front Environ Sci Eng China, 2008, 2(4): 397–409.DOI: 10.1007/s11783-008-0074-0 |
| [59] | Liang CJ, Lee IL, Hsu IY, et al. Persulfate oxidation of trichloroethylene with and without iron activation in porous media.Chemosphere, 2008, 70(3): 426–435.DOI: 10.1016/j.chemosphere.2007.06.077 |
| [60] | Liang CH, Huang NB, Wang H. Corrosion behavior of 09Cr2AlMoRE steel in seawater with sulfate-reducing bacteria.J Dalian Mar Univ, 2010, 36(1): 73–76.(in Chinese). 梁成浩, 黄乃宝, 王华. 海水中硫酸盐还原菌对09Cr2AlMoRE钢的腐蚀行为.大连海事大学学报, 2010, 36(1): 73-76. |
| [61] | Blakemore RP, Short KA, Bazylinski DA, et al. Microaerobic conditions are required for magnetite formation within Aquaspirillum magnetotacticum.Geomicrobiol J, 1985, 4(1): 53–71.DOI: 10.1080/01490458509385920 |
| [62] | Lovley DR, Stolz JF, Nord GL, et al. Anaerobic production of magnetite by a dissimilatory iron-reducing microorganism.Nature, 1987, 330(6145): 252–254.DOI: 10.1038/330252a0 |
| [63] | Seech AG, Cairns JE, Marvan IJ. Method for dehalogenation and degradation of halogenated organic contaminants: US, 5411664. 1995-05-02. |
| [64] | Quinn J, Geiger C, Clausen C, et al. Field demonstration of DNAPL dehalogenation using emulsified zero-valent iron.Environ Sci Technol, 2005, 39(5): 1309–1318.DOI: 10.1021/es0490018 |
| [65] | Bouwer EJ, Mccarty PL. Transformations of halogenated organic compounds under denitrification conditions.Appl Environ Microbiol, 1983, 45(4): 1295–1299. |
| [66] | Novak PJ, Daniels L, Parkin GF. Enhanced dechlorination of carbon tetrachloride and chloroform in the presence of elemental iron and Methanosarcina barkeri, Methanosarcina thermophila, or Methanosaeta concillii.Environ Sci Technol, 1998, 32(10): 1438–1443.DOI: 10.1021/es970785h |
| [67] | Kennedy LG. Treating toxic solvents and heavy metal contaminants in groundwater and soil using iron sulfides microbial geochemical treatment zone: US, 6884352. 2005-04-26. |
| [68] | Kennedy LG, Everett JW, Becvar E, et al. Field-scale demonstration of induced biogeochemical reductive dechlorination at Dover Air Force Base, Dover, Delaware.J Contam Hydrol, 2006, 88(1/2): 119–136. |
| [69] | Gao YH, Zhao TT, Xing ZL, et al. Effects of copper on biodegradation mechanism of trichloroethylene by mixed microorganisms.Chin J Biotech, 2016, 32(5): 621–634.(in Chinese). 高艳辉, 赵天涛, 邢志林, 等. 铜离子对混合菌群降解三氯乙烯的影响与机制分析.生物工程学报, 2016, 32(5): 621-634. |
| [70] | Fennell DE, Gossett JM. Microcosms for site-specific evaluation of enhanced biological reductive dehalogenation//H ggblom MM, Bossert ID, Eds. Dehalogenation. Boston: Springer, 2004: 385–420. |
| [71] | Aulenta F, Pera A, Rossetti S, et al. Relevance of side reactions in anaerobic reductive dechlorination microcosms amended with different electron donors.Water Res, 2007, 41(1): 27–38.DOI: 10.1016/j.watres.2006.09.019 |
| [72] | L ffler FE, Tiedje JM, Sanford RA. Fraction of electrons consumed in electron acceptor reduction and hydrogen thresholds as indicators of halorespiratory physiology.Appl Environ Microbiol, 1999, 65(9): 4049–4056. |
| [73] | Robinson C, Barry DA, Mccarty PL, et al. pH control for enhanced reductive bioremediation of chlorinated solvent source zones.Sci Total Environ, 2009, 407(16): 4560–4573.DOI: 10.1016/j.scitotenv.2009.03.029 |
| [74] | Heimann AC, Friis AK, Jakobsen R. Effects of sulfate on anaerobic chloroethene degradation by an enriched culture under transient and steady-state hydrogen supply.Water Res, 2005, 39(15): 3579–3586.DOI: 10.1016/j.watres.2005.06.029 |
| [75] | Wei N, Finneran KT. Influence of ferric iron on complete dechlorination of trichloroethylene (TCE) to ethene: Fe (Ⅲ) reduction does not always inhibit complete dechlorination.Environ Sci Technol, 2011, 45(17): 7422–7430.DOI: 10.1021/es201501a |
| [76] | Paul L, Herrmann S, Koch CB, et al. Inhibition of microbial trichloroethylene dechorination by Fe (Ⅲ) reduction depends on Fe mineralogy: A batch study using the bioaugmentation culture KB-1.Water Res, 2013, 47(7): 2543–2554.DOI: 10.1016/j.watres.2013.02.029 |
| [77] | Dolinová I, Czinnerová M, Dvo?ák L, et al. Dynamics of organohalide-respiring bacteria and their genes following in-situ chemical oxidation of chlorinated ethenes and biostimulation.Chemosphere, 2016, 157: 276–285.DOI: 10.1016/j.chemosphere.2016.05.030 |
| [78] | Chapelle FH, Bradley PM, Casey CC. Behavior of a chlorinated ethene plume following source-area treatment with Fenton's reagent.Ground Water Monit Remediat, 2010, 25(2): 131–141. |
| [79] | Michaell MC, Bouwer Edward EJ, Adriaens P. Carbon tetrachloride transformation in a model iron-reducing culture: relative kinetics of biotic and abiotic reactions.Environ Sci Technol, 2002, 36(3): 403–410.DOI: 10.1021/es010923+ |
| [80] | Kocur CMD, Lomheim L, Boparai HK, et al. Contributions of abiotic and biotic dechlorination following carboxymethyl cellulose stabilized nanoscale zero valent iron injection.Environ Sci Technol, 2015, 49(14): 8648–8656.DOI: 10.1021/acs.est.5b00719 |
| [81] | Lee M, Wells E, Wong YK, et al. Relative contributions of Dehalobacter and zero valent iron in the degradation of chlorinated methanes.Environ Sci Technol, 2015, 49(7): 4481–4489.DOI: 10.1021/es5052364 |
| [82] | Lampron KJ, Chiu PC, Cha DK. Reductive dehalogenation of chlorinated ethenes with elemental iron: the role of microorganisms.Water Res, 2001, 35(13): 3077–3084.DOI: 10.1016/S0043-1354(01)00017-3 |
