Cheng Shaoan, Liu Hong, Logan Bruce E
Department of Civil and Environmental Engineering, The Penn State Hydrogen Energy (H2E) Center, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Environ Sci Technol. 2006 Apr 1;40(7):2426-32. doi: 10.1021/es051652w.
The maximum power generated in a single-chamber air-cathode microbial fuel cell (MFC) has previously been shown to increase when the spacing between the electrodes is decreased from 4 to 2 cm. However, the maximum power from a MFC with glucose (500 mg/L) decreased from 811 mW/ m2 (R(ex) = 200 omega, Coulombic efficiency of CE = 28%) to 423 mW/m2 (R(ex) = 500 omega, CE = 18%) when the electrode spacing was decreased from 2 to 1 cm (batch mode operation, power normalized by cathode projected area). This decrease in power was unexpected as the internal resistance decreased from 35 omega (2-cm spacing) to 16 omega (1-cm spacing). However, providing advective flow through the porous anode toward the cathode substantially increased power, resulting in the highest maximum power densities yet achieved in an air-cathode system using glucose or domestic wastewater as substrates. For glucose, with a 1-cm electrode spacing and flow through the anode with continuous flow operation of the MFC, the maximum power increased to 1540 mW/m2 (51 W/m3) and the CE increased to 60%. Using domestic wastewater (255 +/- 10 mg of COD/L), the maximum power density was 464 mW/m2 (15.5 W/m3; CE = 27%). Although flow through the anode could lead to plugging, especially for particulate substrates such as domestic wastewater, the system was operated using glucose for over 42 days without clogging. These results show that power output in this air-cathode single-chamber MFC can be increased by reducing the electrode spacing if the reactors are operated in continuous flow mode with advective flow through the anode toward the cathode.
先前已表明，在单室空气阴极微生物燃料电池（MFC）中，当电极间距从4厘米减小到2厘米时，产生的最大功率会增加。然而，对于以葡萄糖（500毫克/升）为燃料的MFC，当电极间距从2厘米减小到1厘米时（间歇模式运行，功率按阴极投影面积归一化），最大功率从811毫瓦/平方米（R（ex）=200欧姆，库仑效率CE = 28%）降至423毫瓦/平方米（R（ex）=500欧姆，CE = 18%）。功率的这种下降出乎意料，因为内阻从35欧姆（2厘米间距）降至16欧姆（1厘米间距）。然而，通过多孔阳极向阴极提供平流显著提高了功率，在以葡萄糖或生活污水为底物的空气阴极系统中实现了迄今最高的最大功率密度。对于葡萄糖，在MFC连续流运行且有平流通过阳极的情况下，电极间距为1厘米时，最大功率增加到1540毫瓦/平方米（51瓦/立方米），库仑效率增加到60%。使用生活污水（化学需氧量浓度为255±10毫克/升）时，最大功率密度为464毫瓦/平方米（15.5瓦/立方米；CE = 27%）。尽管通过阳极的流动可能导致堵塞，特别是对于像生活污水这样的颗粒状底物，但该系统使用葡萄糖运行了42天以上而未堵塞。这些结果表明，如果反应器以连续流模式运行，且有平流通过阳极流向阴极，那么这种空气阴极单室MFC的功率输出可以通过减小电极间距来提高。
