Department of Civil and Environmental Engineering, 212 Sackett Building, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Environ Sci Technol. 2011 Jul 1;45(13):5834-9. doi: 10.1021/es200979b. Epub 2011 Jun 15.
A new type of bioelectrochemical system for producing electrical power, called a microbial reverse-electrodialysis cell (MRC), was developed to increase voltages and power densities compared to those generated individually by microbial fuel cells (MFCs) or reverse electrodialysis (RED) systems. In RED systems, electrode overpotentials create significant energy losses due to thermodynamically unfavorable electrode reactions, and therefore a large number of stacked cells must be used to have significant energy recovery. This results in high capital costs for the large number of membranes, and increases energy losses from pumping water through a large number of cells. In an MRC, high overpotentials are avoided through oxidation of organic matter by exoelectrogenic bacteria on the anode and oxygen reduction on the cathode. An MRC containing only five pairs of RED cells, fed solutions typical of seawater (600 mM NaCl) and river water (12 mM NaCl) at 0.85 mL/min, produced up to 3.6 W/m(2) (cathode surface area) and 1.2-1.3 V with acetate as a substrate. Pumping accounted for <2% of the produced power. A higher flow rate (1.55 mL/min) increased power densities up to 4.3 W/m(2). COD removal was 98% with a Coulombic efficiency of 64%. Power production by the individual components was substantially lower with 0.7 W/m(2) without salinity driven energy, and <0.015 W/m(2) with reduced exoelectrogenic activity due to substrate depletion. These results show that the combination of an MFC and a RED stack synergistically increases performance relative to the individual systems, producing a new type of system that can be used to more efficiently capture salinity driven energy from seawater and river water.
一种新型的生物电化学系统，称为微生物逆向电渗析电池（MRC），被开发出来以提高电压和功率密度，与单独由微生物燃料电池（MFC）或逆向电渗析（RED）系统产生的电压和功率密度相比。在 RED 系统中，由于电极反应热力学上不利，电极过电势会导致显著的能量损失，因此必须使用大量堆叠的电池才能实现显著的能量回收。这导致大量膜的资本成本很高，并增加了通过大量电池泵送水的能量损失。在 MRC 中，通过阳极的放电子细菌对有机物的氧化和阴极的氧气还原来避免高过电势。一个仅包含五对 RED 电池的 MRC，以 0.85 mL/min 的速度进料典型海水（600 mM NaCl）和河水（12 mM NaCl）溶液，在以乙酸盐为底物时，可产生高达 3.6 W/m²（阴极表面积）和 1.2-1.3 V 的电压。泵送仅占产生功率的<2%。更高的流速（1.55 mL/min）可将功率密度提高到 4.3 W/m²。COD 去除率为 98%，库仑效率为 64%。在没有盐度驱动能量的情况下，单个组件的功率产生要低得多，为 0.7 W/m²，而由于底物耗尽导致放电子活性降低，功率产生要低得多，<0.015 W/m²。这些结果表明，MFC 和 RED 堆叠的组合相对于单个系统协同地提高了性能，产生了一种新型系统，可更有效地从海水和河水中捕获盐度驱动的能量。
