Iron-Cycling-Constructed Wetland-Microbial Fuel Cell-Enhanced Removal of Sartans: The Overlooked Singlet Oxygen and...

The global challenge of population aging has led to an increase in the utilization of cardiovascular drugs such as sartans, which are frequently detected in aquatic environments and necessitate advanced treatment. Current sartan removal technologies are limited by their requirement for strict reaction conditions and the potential formation of toxic byproducts. This study presents a novel iron-cycling-constructed wetland-microbial fuel cell (Fe-CWMFC) that combines biotic and abiotic processes to effectively degrade sartans (94.4 ± 3.5%-95.9% ± 3.3%). Mass balance analysis revealed that direct microbial degradation pathways made the highest contribution (40.7-44.5%), followed by ROS-driven degradation (20.3-21.8%), substrate adsorption (26.1-29.7%), and plant uptake (2.3-2.5%). Iron cycling enhanced ROS-driven degradation, with 11.3-13.3% derived from biotic ¹O₂ and 7.0-9.3% derived from abiotic ¹O₂. Metagenomic binning analysis identified 60 MAGs (e.g., Thiobacillus, Nitrosomonas) with sartan degradation potential, which harbor genes encoding functional enzymes (e.g., decarboxylase, dehydroxylase, and demethylase). By combining biodegradation and ROS-driven degradation to target functional groups (e.g., -COOH, -OH, and -CH₃) in sartans, the toxicity was significantly reduced. This research enhances our understanding of the combined role of ROS and microorganisms in micropollutant removal and highlights Fe-CWMFC as a high-efficiency, sustainable, and low-toxicity treatment technology for complex environmental applications.