Synergetic Relay of Phenoxyl‐Radical‐Mediated Oligomerization and Aromatic‐Ring‐Opening Processes for Organic Wastewater Treatment

Abstract

ABSTRACT Efficient removal of recalcitrant aromatic compounds in organic wastewater is hindered by ambiguous reaction pathways in conventional single‐process polymerization or ring‐opening mineralization. Herein, we report a synergistic relay strategy that integrates phenoxyl‐radical‐mediated oligomerization and aromatic‐ring‐opening pathways for the highly efficient treatment of organic wastewater. This approach couples an initial high‐valence iron‐oxo species (HVIO)‐driven oligomerization via formal hydrogen atom transfer at one site with a subsequent singlet oxygen ( 1 O 2 )‐mediated ring‐opening reaction at an adjacent site, enabled by a dual‐single‐atom Fe 1 Cu 1 /TiO 2 photocatalyst. Under solar‐light irradiation, photoinduced electrons are transferred to peroxymonosulfate (PMS) at the Fe 1 site, which acts as a critical activator to generate HVIO for oligomerization‐based removal. Simultaneously, holes oxidize PMS at the Cu 1 site to produce 1 O 2 , leading to efficient aromatic‐ring‐opening. This sequential strategy achieved nearly 72% chemical oxygen demand removal with 23% carbon recovery into separable polymer products within 10 min for the phenol and ultimately reached complete removal with a rate constant of 1.21 min −1 , significantly surpassing most reported values. Moreover, the system exhibited excellent stability and long‐term activity in a custom‐designed photo‐filter reactor, highlighting its practical potential. By coupling oligomerization and mineralization, this work provides a groundbreaking and versatile platform for treating complex organic wastewater.