Hydrogen production in a single chamber microbial electrolysis cell lacking a membrane
Hydrogen production in a single chamber microbial electrolysis cell lacking a membrane
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DOI：
10.1021/es8001822
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发表时间：
2008-05-01
影响因子：
11.4
通讯作者：
Logan, Bruce E.
中科院分区：
文献类型：
--
作者：
Call, Douglas;Logan, Bruce E.
氢气可以在微生物电解细胞（MECs）中通过电制氢产生，其产量比发酵高，能源效率比水电解高。假设在MEC中需要一层膜来避免由于细菌消耗产物气体而造成的氢损失。然而，在MEC中，尽管电极之间没有膜（施加电压0.3 < E-ap < 0.8 V；溶液电导率7.5 mS/cm），仍然实现了高阴极氢回收率（78 +/- 1%至96 +/- 1%）。在E-ap = 0.8 V的电压下，通过使用无膜系统、石墨纤维刷阳极和紧凑的电极间距，产氢率达到最大值3.12 +/- 0.02 m(3) H-2/m(3)反应器每天（292 +/- 1A/m(3)）。这一产量是以前MEC研究中获得的两倍多。相对于电输入的能量效率随着外加电压从406 +/- 6% （E-ap = 0.3 V）下降到194 +/- 2% （E-ap = 0.8 V）。相对于Eap和衬底能量的总能量效率平均为78 +/- 4%，最高为86 +/- 2% (1.02 +/- 0.05 m（3) H-2/m(3)天，E-ap = 0.4 V）。在E-ap = 0.2 V时，由于反应器的循环时间较长，氢气的回收率大幅下降，甲烷浓度从平均1.9 +/- 1.3% （E-ap = 0.3-0.8 V）上升到28%。当E-ap = 0.3 ~ 0.6 V时，将溶液电导率提高到20 mS/cm可提高产氢率，但在E-ap > 0.6 V时，反应器性能不一致。这些结果表明，在没有膜的单室MEC中，高氢气回收率和生产率是可能的，这可能会降低这些系统的成本，并允许新的和更简单的设计。
Hydrogen gas can be produced by electrohydrogenesis in microbial electrolysis cells (MECs) at greater yields than fermentation and at greater energy efficiencies than water electrolysis. It has been assumed that a membrane is needed in an MEC to avoid hydrogen losses due to bacterial consumption of the product gas. However, high cathodic hydrogen recoveries (78 +/- 1% to 96 +/- 1%) were achieved in an MEC despite the absence of a membrane between the electrodes (applied voltages of 0.3 < E-ap < 0.8 V; 7.5 mS/cm solution conductivity). Through the use of a membrane-less system, a graphite fiber brush anode, and close electrode spacing, hydrogen production rates reached a maximum of 3.12 +/- 0.02 m(3) H-2/m(3) reactor per day (292 +/- 1A/m(3)) at an applied voltage of E-ap = 0.8 V. This production rate is more than double that obtained in previous MEC studies. The energy efficiency relative to the electrical input decreased with applied voltage from 406 +/- 6% (E-ap = 0.3 V) to 194 +/- 2% (E-ap = 0.8 V). Overall energy efficiency relative to both Eap and energy of the substrate averaged 78 +/- 4%, with a maximum of 86 +/- 2% (1.02 +/- 0.05 m(3) H-2/m(3) day, E-ap = 0.4 V). At E-ap = 0.2 V, the hydrogen recovery substantially decreased, and methane concentrations increased from an average of 1.9 +/- 1.3% (E-ap = 0.3-0.8 V) to 28 0% of the gas, due to the long cycle time of the reactor. Increasing the solution conductivity to 20 mS/cm increased hydrogen production rates for E-ap = 0.3-0.6 V, but consistent reactor performance could not be obtained in the high conductivity solution at E-ap > 0.6 V. These results demonstrate that high hydrogen recovery and production rates are possible in a single chamber MEC without a membrane, potentially reducing the costs of these systems and allowing for new and simpler designs.