Promoted electromethanosynthesis in a two-chamber microbial electrolysis cells (MECs) containing a hybrid biocathode covered with graphite felt (GF)
Promoted electromethanosynthesis in a two-chamber microbial electrolysis cells (MECs) containing a hybrid biocathode covered with graphite felt (GF)
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DOI：
10.1016/j.cej.2015.09.071
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发表时间：
2016-01
影响因子：
15.1
通讯作者：
Guangyin Zhen;Xueqin Lu;Takurou Kobayashi;Gopalakrishnan Kumar;Kaiqin Xu
中科院分区：
文献类型：
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作者：
Guangyin Zhen;Xueqin Lu;Takurou Kobayashi;Gopalakrishnan Kumar;Kaiqin Xu
微生物电产甲烷是利用生物阴极上具有电化学活性的生物膜将二氧化碳转化为甲烷，为可再生能源的储存提供了新的途径。控制电子交换和甲烷生成效率的一个关键因素是电极材料。为了促进甲烷的生产，开发了一种用石墨毡（GF）修饰普通碳棒的生物阴极（以下简称“混合GF-生物阴极”），并在双室微生物电解池（MECs）中进行了评估。在−1.4 V电位下，混合gf -生物阴极孵育24 h后甲烷产量达到80.9 mL/L，库仑效率为194.4%。通过对三种底物（CO2、n2和H2-CO2[80:20]）的冲洗实验表明，直接电子转移比中间h2o2对电甲烷生成的贡献更大。循环伏安法表明，GF提高了微生物电催化活性，降低了甲烷生成所需的阴极过电位。扫描电镜和荧光原位杂交分析证实，三维GF为电活性微生物的生长提供了丰富的空间，并通过“人工菌毛”的切断促进了电子交换（如阴极到细胞等）。研究表明，具有开放结构和高导电性的GF在提高电产甲烷效率方面具有很大的潜力。
Microbial electromethanogenesis, relying on electrochemically active biofilm on biocathode to convert carbon dioxide to methane, provides a novel approach for renewable energy storage. One key factor that governs electron exchange and methane formation efficiencies is the electrode material. To promote methane production, a biocathode via modifying plain carbon stick with a layer of graphite felt (GF) (hereafter referred as “hybrid GF-biocathode”) was developed and evaluated in a two-chamber microbial electrolysis cells (MECs). Methane production with hybrid GF-biocathode reached 80.9 mL/L at the potential of −1.4 V after 24 h of incubation with coulombic efficiency of 194.4%. The tests by flushing three substrates (CO2, N2and H2–CO2[80:20]) revealed that direct electron transfer rather than intermediate H2contributed more to the electromethanogenesis. Cyclic voltammetry showed that GF enhanced the microbial electrocatalysis activity and reduced the cathode overpotential needed for methane production. Scanning electron microscope and fluorescencein situhybridization analysis confirmed that the three-dimensional GF afforded the abundant space for the growth of electroactive microorganisms and promoted the electron exchange (e.g. cathode-to-cell etc.) via severing as “artificial pili”. This study reveals that GF with the open structure and high conductivity has the substantial potential to upgrade electromethanogenesis efficiency.