Flow-through filter divided electrolytic cell enables highly efficient water purification via spatiotemporal...

Emerging contaminants with contrasting electronic structures respond differently to molecular ozone (O₃) and hydroxyl radicals (•OH), yet conventional electro-peroxone systems mainly exploit cathodic O₃ activation while leaving the acidic anodic chamber underutilized. Here, a hydrophilic carbon-fiber-membrane-divided, single-pass flow-through GF/EP reactor was developed to convert the anodic chamber into an active O₃-preserving oxidation zone and regulate oxidant exposure by reversing the influent direction. In the cathode-to-anode (C-A) configuration, upstream H₂O₂/HO₂^--mediated O₃ activation increased the apparent •OH exposure to 0.59 × 10^-10 M s, achieving 96.0% ibuprofen (electron-deficient contaminant) removal with a k_obs of 0.101 min^-1, compared with 82.3% and 0.076 min^-1 in A-C. Conversely, the upstream acidic anodic region in A-C preserved molecular O₃ and promoted selective electrophilic oxidation of electron-rich contaminants, yielding 99% benzotriazole removal with a k_obs of 0.103 min^-1. Product identification and DFT calculations revealed configuration-dependent pathways and toxicity evolution. Matching influent direction with contaminant reactivity reduced the specific energy consumption for ibuprofen mineralization to 0.16 kWh g^-1. The system also maintained over 80% ibuprofen removal and achieved 47% COD removal in secondary effluent. These results establish flow-direction-regulated oxidant sequencing as a simple and energy-efficient strategy for treating chemically diverse contaminants.