Exploiting the self-driven potential of secondary effluent organic matter for peroxymonosulfate activation and...

This study pioneers a waste-treats-waste strategy to address the dual challenges of removing secondary effluent organic matter (EfOM) and minimizing resource input in advanced oxidation processes. The results demonstrate that photoexcited EfOM effectively activate peroxymonosulfate (PMS), achieving self-degradation without external catalyst and intensive energy input. Resin fractionation of EfOM based on hydrophobicity and hydrophilicity reflected that the different systems achieved 14.7 %-26.7 % decomposition of 1 mM PMS and 11 %-20 % reduction in UV₂₅₄ under simulated solar light. The hydrophobic base (HOB) fraction exhibited the highest PMS activation efficiency of 2.7 % per mg/L dissolved organic carbon, due to its aromatic characteristic with strong electron-donating capacity, while the aliphatic-rich hydrophobic neutral (HON) fraction achieved efficient mineralization. The metastable triplet-state EfOM acted as the curcial intermediate enabling electron transfer to PMS, predominantly generating ¹O₂ with minor amounts of •OH and SO₄^•- to facilitate EfOM degradation. Molecular-level analysis via FT-ICR-MS revealed preferential degradation of lignins, lipids and unsaturated/reduced state CHO and CHOS compounds, which further transformed into saturated/oxidized state fragments and ultimately carboxylic acids or mineralized products. Among 26 identified transformation pathways, oxygenation, dealkylation and amine modification dominated, with distinct route preferences among fractions reflecting their structural differences. The system exhibited strong anti-interference capability against common inorganic anions, and maintained effectiveness in treating unfractionated secondary effluent under natural solar light, confirming its potential for practical implementation. By leveraging the inherent photochemical properties of EfOM to drive a self-sustaining advanced oxidation process, this approach presents an eco-friendly alternative for wastewater treatment.