Data_Sheet_1_Effect of Electrode Properties on the Performance of a Photosynthetic Microbial Fuel Cell for Atrazine Detection.docx

The growing use of herbicides in agriculture poses increasing concerns on the pollution of water systems worldwide. To be able to assess the presence of these compounds in waters and limit their impact on human health and ecosystems, the development of effective in-situ monitoring tools is key. Yet, many existing sensing technologies are not suitable for in-situ and remote applications, due to challenges in portability, durability, cost, and power requirements. In this study, we explore for the first time the use of an algae-assisted cathode in a photosynthetic microbial fuel cell (p-MFC) as a self-powered dissolved oxygen probe for herbicides detection in water. The cathode is enriched with the alga Scenedesmus obliquus and two different electrode materials are tested, graphite felt and indium tin oxide, which differ in porosity, surface roughness, and transparency. Despite the much larger specific surface area of graphite felt compared to indium tin oxide, the current generated under light was only 10 times larger (109 ± 2 μA vs. 10.5 ± 0.6 μA) and eight times larger in the dark (37 ± 5 vs. 4.2 ± 0.6 μA). By generating a current output that correlates with the dissolved oxygen in the catholyte, the resulting p-MFCs could detect the EU legal atrazine concentration limit of 0.1 μg L−1. The use of graphite felt led to shorter response times and better sensitivity, as a result of the greater current baseline. In both cases, the current baseline was recovered after exposure of the sensor to frequent toxic events, thus showing the resilience of the cathodic biofilm and the potential of the p-MFCs for early warnings of herbicides pollution in water.

农业领域除草剂使用的日益广泛，对全球水系统的污染问题提出了日益严峻的挑战。为了能够评估这些化合物在水体中的存在并限制其对人类健康和生态系统的影响，开发有效的原位监测工具至关重要。然而，许多现有的传感技术由于便携性、耐用性、成本和电力需求等方面的挑战，并不适用于原位和远程应用。在本研究中，我们首次探索了在光合微生物燃料电池（p-MFC）中利用藻类辅助阴极作为自供电溶解氧探头，用于检测水体中除草剂的方法。该阴极富含斜生衣藻（Scenedesmus obliquus）和两种不同的电极材料，即石墨毡和氧化铟锡，它们在多孔性、表面粗糙度和透明度方面存在差异。尽管与氧化铟锡相比，石墨毡具有更大的比表面积，但在光照下产生的电流仅为10倍（109 ± 2 μA vs. 10.5 ± 0.6 μA），在黑暗中则为8倍（37 ± 5 vs. 4.2 ± 0.6 μA）。通过产生与阴极电解液中溶解氧相关的电流输出，所得到的p-MFCs能够检测到欧盟法定三嗪浓度限制0.1 μg L−1。石墨毡的使用导致了更短的响应时间和更好的灵敏度，这是由于更大的电流基线所致。在两种情况下，电流基线在传感器暴露于频繁的有毒事件后均得以恢复，从而展示了阴极生物膜的抗逆性和p-MFCs在早期预警水体中除草剂污染方面的潜力。