Kinetic experiments for evaluating the Nernst-Monod model for anode-respiring bacteria (ARB) in a biofilm anode.
Kinetic experiments for evaluating the Nernst-Monod model for anode-respiring bacteria (ARB) in a biofilm anode.
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DOI：
10.1021/es800970w
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发表时间：
2008-07
影响因子：
11.4
通讯作者：
César I. Torres;Andrew K. Marcus;P. Parameswaran;B. Rittmann
中科院分区：
文献类型：
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作者：
César I. Torres;Andrew K. Marcus;P. Parameswaran;B. Rittmann
阳极呼吸细菌（ARB）能够将电子从还原底物转移到固体电极。在此之前，我们开发了一个基于Nernst-Monod方程的生物膜模型来描述ARB通过固体导电矩阵传递电子的阳极潜在损失。在这项工作中，我们开发了一个实验装置来证明Nernst-Monod方程能够很好地表示ARB生物膜中的阳极潜在损失。我们使用低扫描循环伏安法（LSCV）在连续模式下生长在醋酸盐上的石墨电极上的ARB生物膜的整个生长阶段。9种lscv的(j)V响应符合Nernst-Monod方程，30℃时的半饱和电位（E(KA)）为-0.425 +/- 0.002 V vs Ag/AgCl （-0.155 +/- 0.002 V vs SHE）。在电流密度饱和时，醋酸盐电位的阳极电位损失约为0.225 V，这一损失由微生物群落的E（KA）值决定。高电流密度下的lscv与Nernst-Monod理想形状没有明显偏差，表明生物膜基质（kappa(bio)）的电导率足够高（>或= 0.5 mS/cm），因此潜在损耗不会影响生物膜阳极的性能。我们的研究结果证实了Nernst-Monod方程对导电生物膜阳极的适用性，并为微生物燃料电池中主导阳极潜在损失的过程提供了见解。
Anode-respiring bacteria (ARB) are able to transfer electrons from reduced substrates to a solid electrode. Previously, we developed a biofilm model based on the Nernst-Monod equation to describe the anode potential losses of ARB that transfer electrons through a solid conductive matrix. In this work, we develop an experimental setup to demonstrate how well the Nernst-Monod equation is able to represent anode potential losses in an ARB biofilm. We performed low-scan cyclic voltammetry (LSCV) throughout the growth phase of an ARB biofilm on a graphite electrode growing on acetate in continuous mode. The (j)V response of 9 LSCVs corresponded well to the Nernst-Monod equation, and the half-saturation potential (E(KA)) was -0.425 +/- 0.002 V vs Ag/AgCl at 30 degrees C (-0.155 +/- 0.002 V vs SHE). Anode-potential losses from the potential of acetate reached approximately 0.225 V at current density saturation, and this loss was determined by our microbial community's E(KA) value. The LSCVs at high current densities showed no significant deviation from the Nernst-Monod ideal shape, indicating that the conductivity of the biofilm matrix (kappa(bio)) was high enough (> or = 0.5 mS/cm) that potential loss did not affect the performance of the biofilm anode. Our results confirm the applicability of the Nernst-Monod equation for a conductive biofilm anode and give insights of the processes that dominate anode potential losses in microbial fuel cells.