基于微生物电解电池的BOD传感器基础研究

Biochemical oxygen demand (BOD) is an essential parameter in water quality detection. The traditional BOD5 method is tedious and time-consuming, so it cannot be used for real-time online measurement. As a BOD biosensor, microbial fuel cell ( MFC) has the advantages of easy operation and quick response. As a result, it has developed very fast recently. However, the oxygen reduction reaction in the cathode of MFC is sluggish due to the unfavorable condition. In addition, oxygen in the cathode will diffuse to the anode and consequently deteriorate the electricity generation by the exoelectrogens. Therefore, MFC-based BOD sensor typically has low output current, long response time, narrow detection range, low sensitivity and poor stability. In this project, an microbial electrolysis cell (MEC) will be constructed for BOD detection by apply a voltage to an MFC, which will solve the above problems well. Meanwhile, nano-structured iron oxide deposited on graphite felts surface will be prepared via thermal decomposition of the iron pentacarbonyl. This highly active material can accelerate the extracellular electron transfer of the exoelectrogens in the anode. The structure of the MEC-based BOD sensor will be optimized and the factors affecting the operation will be examined. The performance of the MEC-based BOD sensor will be comprehensively investigated and evaluated. The project can provide an effective method for real-time online BOD detection.

生化需氧量（BOD）是水质检测的重要指标。传统的BOD5检测方法过程繁琐且耗时长，不能用于实时在线检测。微生物燃料电池 (Microbial Fuel Cell, MFC)作为BOD检测技术，具有操作简单和响应较快等优点，近年来发展很快。但MFC阴极氧还原效率很低，同时氧气扩散到阳极影响微生物的产电。因此，MFC型BOD传感器存在输出电流小、响应时间较长、检测范围窄、灵敏度低以及稳定性差等问题。本项目通过在MFC外部加一电压，构建基于微生物电解电池（Microbial Electrolysis Cell，MEC）的BOD传感器来解决这些问题。同时，采用羰基铁热沉积法，制备高催化活性的纳米氧化铁阳极，加速产电微生物在阳极的胞外电子传递。优化MEC型BOD传感器的结构并研究其运行的影响因素。综合考察评价MEC型BOD传感器的检测性能。该项目可为BOD的实时在线检测提供一种有效的方法。

生化需氧量（Biochemical Oxygen Demand，BOD）是水质检测的重要指标。传统的BOD5检测方法过程繁琐且耗时长，不能用于快速检测。本项目采用微生物电解电池（Microbial Electrolysis Cell，MEC）作为传感器，根据MEC的峰电流和BOD的响应关系，来实现BOD的快速检测。项目制备了两种高性能阳极材料，分别是铁硫掺杂的生物炭阳极以及羟基氧化铁负载的三维多孔块状碳阳极。铁硫掺杂的生物炭阳极有效提高了电活性表面积、亲水性、生物相容性以及电化学催化活性，有效地强化了产电微生物和电极的电子传递。羟基氧化铁负载的三维多孔块状碳阳极具有良好的三维结构，为微生物的附着以及底物传质提供优异的条件。该种阳极比表面积巨大，电导率为350Ωμm，具有优异的导电性，此外，该材料的表面具有含氧官能团，不仅能提高材料的亲水性和生物相容性，还能通过氢键加速电子的传递。本项目才有含铁氧化物来筛选、富集和驯化产电微生物，得到了高效的产电生物膜。项目构建了MEC型BOD传感器，通过提高离子交换膜面积和优化运行条件，提高的MEC的性能。项目重点研究了MEC型BOD传感器各项性能。MEC型BOD传感器的输出电流信号较强（mA级）并且响应快，一般只需要18-72分钟。该传感器在10-180 mg/L的范围内，具有良好的线性关系。此外，该传感器的重现性好，稳定性高。本项目为水中BOD的快速检测，提供了一种全新的途径，具有良好的应用前景。