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首页> 外文期刊>Environmental Science & Technology >Zero-Valent Iron Enhances Biocathodic Carbon Dioxide Reduction to Methane
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Zero-Valent Iron Enhances Biocathodic Carbon Dioxide Reduction to Methane

机译：零价铁可增强生物阴极二氧化碳还原为甲烷的能力

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摘要

Methanogenic bioelectrochemical systems (BESs), which convert carbon dioxide (CO_2) directly to methane (CH_4), promise to be an innovative technology for anaerobic digester biogas upgrading. Zero-valent iron (ZVI), which has previously been used to improve CH_4 production in anaerobic digesters, has not been explored in methanogenic biocathodes. Thus, the objective of this study was to assess the effect of biocathode ZVI on BES performance at 1 and 2 g/L initial ZVI concentrations and at various cathode potentials (—0.65 to —0.80 V versus SHE). The total CH_4 produced during a 7-day feeding cycle with 1 and 2 g/L initial ZVI was 2.8- and 2.9-fold higher, respectively, than the mean CH_4 production in the four prior cycles without ZVI addition. Furthermore, CH_4 production by the ZVI-amended biocathodes remained elevated throughout three subsequent feeding cycles, despite catholyte replacement and no new ZVI addition. The fourth cycle following a single ZVI addition of 1 g/L and 2 g/L yielded 12396 and 231% more total CH_4 than in the non-ZVI cycles, respectively. The higher CH_4 production could not be fully explained by complete anaerobic oxidation of the ZVI and utilization of produced H_2 by hydrogenotrophic methanogens. Microbial community analysis showed that the same phylotype, most closely related to Methanobrevibacter arboriphilus, dominated the archaeal community in the ZVI-free and ZVI-amended biocathodes. However, the bacterial community experienced substantial changes following ZVI exposure, with more Proteobacteria and fewer Bacteroidetes in the ZVI-amended biocathode. Furthermore, it is likely that a redox-active precipitate formed in the ZVI-amended biocathode, which sorbed to the electrode and/or biofilm, acted as a redox mediator, and enhanced electron transfer and CH_4 production. Thus, ZVI may be used to increase biocathode CH_4 production, assist in the start-up of an electromethanogenic biocathode, and/or maintain microbial activity during voltage interruptions.
机译：产甲烷生物电化学系统（BESs）将二氧化碳（CO_2）直接转化为甲烷（CH_4），有望成为厌氧消化池沼气升级的创新技术。零价铁（ZVI）以前曾用于提高厌氧消化池中CH_4的产量，但尚未在产甲烷的生物阴极中进行探索。因此，本研究的目的是评估生物阴极ZVI在1和2 g / L初始ZVI浓度以及各种阴极电势（相对于SHE为-0.65至-0.80 V）下对BES性能的影响。在7天的饲喂周期中，初始ZVI为1和2 g / L的总CH_4分别比不添加ZVI的四个先前周期中的平均CH_4产量高2.8倍和2.9倍。此外，尽管更换了阴极电解液且未添加新的ZVI，但经过ZVI修饰的生物阴极的CH_4产量在随后的三个进料周期中仍然保持较高水平。单个ZVI添加1 g / L和2 g / L后的第四个循环分别比非ZVI循环多产生12396和231％的CH_4。 ZVI的完全厌氧氧化和氢营养型产甲烷菌对产生的H_2的利用不能完全解释CH_4较高的产生。微生物群落分析表明，与无烟甲烷甲烷杆菌最密切相关的相同系统型在无ZVI和经ZVI修饰的生物阴极中主导古细菌群落。然而，ZVI暴露后，细菌群落发生了重大变化，在ZVI修饰的生物阴极中，更多的变形杆菌和更少的拟杆菌。此外，很可能在吸附了电极和/或生物膜的ZVI改性生物阴极中形成的氧化还原活性沉淀物起氧化还原介质的作用，并增强了电子转移和CH_4的产生。因此，ZVI可用于增加生物阴极CH_4的产量，协助启动产甲烷的生物阴极，和/或在中断电压期间维持微生物活性。

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  • 来源
    《Environmental Science & Technology》 |2017年第21期|12956-12964|共9页
  • 作者

    Christy M. Dykstra; Spyros G. Pavlostathis;

  • 作者单位

    School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, United States;

    School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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