Direct One-Electron-Transfer-Mediated Oligomerization in Electrochemical Membranes Drives Eco-Friendly Removing Halogenated Aromatics

Electrochemical processes for organic wastewater purification face challenges including inadequate mineralization, generation of bubbles and harmful byproducts, and high energy consumption. Herein, we report a direct one-electron transfer-mediated oligomerization strategy using reactive electrochemical membranes (REMs) with tailored atomic defects, enabling simultaneous removal and recycling of halogenated aromatic compounds (HACs) from wastewater. This approach leverages confined microchannels and dual-active sites to promote aromatic radical formation and coupling, converting HACs into halogenated oligomers. The developed system achieved >97.2% removal of 2,4-dichlorophenoxyacetic acid within 0.8 min, and demonstrated 70.2% recovery of oligomers from 1.0 L wastewater with 0.9 mM 4-chlorophenol under low-potential conditions. Electro-oligomerization prevented harmful byproduct formation (e.g., ClO3-, ClO4-) and reduced energy consumption (0.06 kWh m-3), and recovered halogenated oligomers holding potential for industrial reutilization. These findings underscore the promise of REMs-based electro-oligomerization as a sustainable water purification strategy that supports a circular carbon economy through the recovery of high-value oligomers.