Lu Lu, Ren Nanqi, Xing Defeng, Logan Bruce E
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Biosens Bioelectron. 2009 Jun 15;24(10):3055-60. doi: 10.1016/j.bios.2009.03.024. Epub 2009 Mar 25.
Hydrogen can be produced by bacterial fermentation of sugars, but substrate conversion to hydrogen is incomplete. Using a single-chamber microbial electrolysis cell (MEC), we show that additional hydrogen can be produced from the effluent of an ethanol-type dark-fermentation reactor. An overall hydrogen recovery of 83+/-4% was obtained using a buffered effluent (pH 6.7-7.0), with a hydrogen production rate of 1.41+/-0.08 m(3) H(2)/m(3) reactor/d, at an applied voltage of E(ap)=0.6 V. When the MEC was combined with the fermentation system, the overall hydrogen recovery was 96%, with a production rate of 2.11 m(3) H(2)/m(3)/d, corresponding to an electrical energy efficiency of 287%. High cathodic hydrogen recoveries (70+/-5% to 94+/-4%) were obtained at applied voltages of 0.5-0.8 V due to shorter cycle times, and repression of methanogen growth through exposure of the cathode to air after each cycle. Addition of a buffer to the fermentation effluent was critical to MEC performance as there was little hydrogen production using unbuffered effluent (0.0372 m(3) H(2)/m(3)/d at E(ap)=0.6 V, pH 4.5-4.6). These results demonstrate that hydrogen yields from fermentation can be substantially increased by using MECs.
氢气可通过糖类的细菌发酵产生，但底物向氢气的转化并不完全。我们使用单室微生物电解池（MEC）表明，乙醇型暗发酵反应器的流出物可产生额外的氢气。使用缓冲流出物（pH 6.7 - 7.0）时，总氢气回收率为83±4%，在施加电压E(ap)=0.6 V时，氢气产生速率为1.41±0.08 m³ H₂/m³反应器/天。当MEC与发酵系统结合时，总氢气回收率为96%，产生速率为2.11 m³ H₂/m³/天，对应电能效率为287%。由于循环时间较短，且每个循环后通过将阴极暴露于空气中抑制产甲烷菌生长，在0.5 - 0.8 V的施加电压下可获得较高的阴极氢气回收率（70±5%至94±4%）。向发酵流出物中添加缓冲剂对MEC性能至关重要，因为使用未缓冲的流出物时氢气产量很少（在E(ap)=0.6 V、pH 4.5 - 4.6时为0.0372 m³ H₂/m³/天）。这些结果表明，使用MEC可大幅提高发酵产生的氢气产量。
