• 关键词：沉积物微生物燃料电池  在线监测  湿地  突发水污染事件  产电细菌

• 基金项目：国家自然科学基金面上项目（No.42177033）

• 李晨露
• 南京师范大学环境学院;江苏省物质循环与污染控制重点实验室

• 李涛
• 南京师范大学环境学院;江苏省物质循环与污染控制重点实验室

• 李小方
• 中国科学院遗传与发育生物学研究所农业资源研究中心

• 竹原
• 江苏省物质循环与污染控制重点实验室;南京师范大学地理科学学院

• 亓星
• 南京师范大学环境学院

• 韦薇
• 南京师范大学环境学院

• 钟文辉
• 江苏省物质循环与污染控制重点实验室;南京师范大学地理科学学院

• 邓欢
• 南京师范大学环境学院;江苏省物质循环与污染控制重点实验室

• 摘要：我国十分重视对突发性水污染事件的监测和处置.本研究设计了一种实时在线监测重金属污染事件的漂浮阴极沉积物-微生物燃料电池传感器（漂浮阴极SMFC传感器）.该传感器阳极埋设在淹水土壤中，阴极漂浮在水面作为污染响应元件，并向阴极分别加入Zn²⁺、Cd²⁺、Co²⁺、Ni²⁺、Pb²⁺、Cu²⁺、Cr⁶⁺溶液以模拟水体重金属污染事件，以探究该传感器电信号对不同重金属污染的响应特征及机制.结果显示， Cu²⁺和Cr⁶⁺污染引起传感器出现明显的电压峰，而其他5种重金属污染则未引起明显的电信号响应.该传感器电压信号对Cu²⁺污染的最低检测限为5 mg·L^-1，灵敏度为1.06 mV·L·mg^-1，线性范围为5~40 mg·L^-1；Cr⁶⁺污染的最低检测限为40 mg·L^-1，灵敏度为0.17 mV·L·mg^-1，线性范围为40~200 mg·L^-1.X射线光电子能谱（XPS）表征分析显示，Cu²⁺和Cr⁶⁺污染的阴极表面分别存在单质Cu和Cr³⁺，表明Cu²⁺和Cr⁶⁺在阴极表面得电子还原，减弱了 阴极极化效应，引起电压上升.16S rRNA基因测序和定量结果显示，重金属污染前后土壤产电细菌相关属的数量无显著差异且产电细菌产生的基准电压较为平稳，优势产电细菌相关属均包含Bacillus和Clostridium.因此，漂浮阴极SMFC传感器适用于监测湿地水体Cu²⁺和Cr⁶⁺污染 事件，并且能够监测多次污染仍保持稳定运行.该监测技术能够快速发现水污染事件，有助于实现污染的快速处置.

• Abstract：Monitoring and handling of water contamination emergencies are of great importance in China. In this study， a novel sediment microbial fuel cell based sensor with floating cathode （floating-cathode SMFC sensor） was designed for real-time and online monitoring of heavy metal contamination emergencies. The anode of the sensor was embedded in flooded soil， while the cathode was floating on the water surface as a responsive element for heavy metals. Zn²⁺， Cd²⁺， Co²⁺， Ni²⁺， Pb²⁺， Cu²⁺， and Cr⁶⁺ solutions were added to the cathode to simulate heavy metals contamination events in water. The purpose was to explore the response characteristics and mechanism of electrical signals generated by the sensors. The results showed that the sensors generated obvious voltage peaks after Cu²⁺ or Cr⁶⁺ shock， whereas the other five heavy metals did not trigger any obvious electrical signals. The sensors exhibited voltage signals to Cu²⁺ contamination with the minimum detection limit of 5 mg·L^-1， the sensitivity of 1.06 mV·L·mg^-1， and the linear range of 5~40 mg·L^-1， whereas for Cr⁶⁺ contamination， the minimum detection limit， sensitivity， and linear range were 40 mg·L^-1， 0.17 mV·L·mg^-1， and 40~200 mg·L^-1， respectively. X-ray photoelectron spectroscopy （XPS） analysis showed the presence of elemental Cu and Cr³⁺ on the cathodic surface following the contamination of Cu²⁺ and Cr⁶⁺ respectively， indicating that Cu²⁺ and Cr⁶⁺ were reduced by electrons on the cathodic surface， and thus the cathode polarization effect was weakened and the voltage signals were promoted. Sequencing and quantification of 16S rRNA gene showed that the abundance of exoelectrogenic bacteria-associated genera in soil was not decreased significantly（p>0.05） following heavy metals contamination， compared with that before the operation of the sensors， which is consistent with the stable baseline voltage generated by exoelectrogenic bacteria. The dominant exoelectrogenic bacteria-associated genera included Bacillus and Clostridium. We conclude that the floating-cathode SMFC sensor would be suitable for monitoring Cu²⁺ and Cr⁶⁺ contamination emergencies in wetlands and contribute to rapid disposing of contaminants； moreover， it could maintain stable operation after monitoring multiple shocks.

• Key words：sediment microbial fuel cell  online monitoring  wetland  water contamination emergencies  exoelectrogenic bacteria

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