Rewiring electron flow in constructed wetlands: A critical review of iron-catalyzed microbial interface for PFAS...

The environmental persistence and mobility of PFAS continue to challenge traditional remediation technologies. However, modified constructed wetlands incorporating iron-based materials represent a significant advancement, effectively coupling redox geochemistry with microbial metabolism.This review critically examines the role of iron-based substrates as redox-active interfaces within constructed wetland systems, and synthesizes current evidence on their involvement in electron transfer processes. Specifically, we synthesize current evidence on how iron-based materials influence extracellular electron transfer and interspecies electron transfer within microbial consortia, and discuss their potential association with PFAS transformation pathways. By integrating multi-omics insights, we characterize the dynamics at the iron, microbe, and PFAS interface. Finally, we outline potential future research directions aimed at addressing current mechanistic uncertainties. In particular, computational approaches such as density functional theory, combined with thermodynamic and kinetic analyses, together with advanced time-resolved techniques, may provide complementary tools to strengthen mechanistic validation of PFAS transformation under constructed wetland-relevant conditions.