Influence of mediator immobilization on the electrochemically assisted microbial dechlorination of trichloroethene (TCE) and cis-dichloroethene (cis-DCE)
Influence of mediator immobilization on the electrochemically assisted microbial dechlorination of trichloroethene (TCE) and cis-dichloroethene (cis-DCE)
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DOI：
10.1002/jctb.2162
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发表时间：
2009-06-01
影响因子：
3.4
通讯作者：
Majone, Mauro
中科院分区：
文献类型：
--
作者：
Aulenta, Federico;Canosa, Andrea;Majone, Mauro
背景：三氯乙烯（TCE）生物电化学脱氯工艺的开发。在这个新工艺中，固态电极与氧化还原介体（即，甲基紫精，MV）用作TCE的微生物还原脱氯的电子供体。在这项研究中，我们比较了氧化还原介体固定在电极表面或溶解在本体液体中的过程的性能，使用高度富集脱硫杆菌属的培养物，能够将TCE脱氯为顺式-二氯乙烯（cis-DCE），以及高度富集Dehalococcoides spp.结果：短时恒电位（-450 mV vs SHE）实验表明，TCE或cis-DCE在可溶性（500 μ mol L ~（-1））和固定化MV存在下均能脱氯。然而，TCE或cis-DCE脱氯速率与MV修饰电极显着低于可溶性MV。这两种文化产生了显着量的H-2的存在下，电还原，可溶性MV，而没有H-2时，被固定在电极表面的介质，无论施加到电极上的电位，在-425至-500 mV的范围内与SHE.CONCLUSIONS：该过程中，与修饰电极操作，支持TCE的微生物脱氯乙烯。固定化不仅允许将介体保留在系统内，而且还通过防止生物电化学H-2形成来提高过程效率。另一方面，需要开发利用修饰电极提高脱氯率的策略。(C)2009年化学工业协会
BACKGROUND: A bioelectrochemical process for trichloroethene (TCE) dechlorination was developed. In this new process, a solid-state electrode polarized to -450 mV versus the standard hydrogen electrode (SHE), in combination with a redox mediator (i.e., methyl viologen, MV) is employed as an electron donor for the microbial reductive dechlorination of TCE. In this study we compared the performance of the process with the redox mediator immobilized at the surface of electrodes or dissolved in the bulk liquid, using both a culture highly enriched in Desulfitobacterium spp., capable of dechlorinating TCE to cis-dichloroethene (cis-DCE), and a culture highly enriched in Dehalococcoides spp. capable of dechlorinating cis-DCE to ethene.RESULTS: Short-term potentiostatic (-450 mV versus SHE) experiments showed that TCE or cis-DCE was dechlorinated both in the presence of soluble (500 mu mol L-1) and immobilized MV. However, TCE or cis-DCE dechlorination rates with MV-modified electrodes were remarkably lower than with soluble MV. Both cultures produced significant amounts of H-2 in the presence of electrically reduced, soluble MV, whereas no H-2 was produced when the mediator was immobilized at the electrode surface, regardless of the potential applied to the electrode, in the range -425 to -500 mV versus SHE.CONCLUSIONS: The process, operated with modified electrodes, supports the microbial dechlorination of TCE to ethene. Immobilization not only allows retention of the mediator within the system, but also increases process efficiency by preventing bioelectrochemical H-2 formation. On the other hand, strategies to increase dechlorination rates with modified electrodes need to be developed. (C) 2009 Society of Chemical Industry