Interfacial engineering with nanobubbles to enhance the polymerization transfer pathway for efficient water decontamination.

Given the high energy consumption of conventional mineralization in heterogeneous advanced oxidation processes (AOPs), polymerization transfer (PT) pathway offers a sustainable alternative that enables efficient total organic carbon (TOC) abatement with the potential for polymeric products recovery from wastewater. Herein, an innovative interfacial engineering strategy was proposed using nanobubbles (NBs) to enhance the PT pathway in carbon nanotube (CNT)/peroxymonosulfate (PMS) system. We demonstrate that 81% TOC of acetaminophen is removed by NB/CNT/PMS system, which is approximately double and ten-fold higher than those by CNT/PMS and NB/PMS systems, respectively. Molecular structure analysis on CNT surface deposits reveals a substantial increase in C-C and C-O coupling polymeric products in the presence of NBs, confirming that the enhanced TOC removal is predominantly achieved via the PT pathway. Mechanistic studies identify that CNT aggregation on gas-liquid interfaces creates numerous confined microreactors, enhancing electron transfer efficiency and significantly boosting the yields of phenoxy radicals, thus steering the reaction towards polymerization. Furthermore, the NBs suppresses CNT deactivation, maintaining high catalytic activity over 50 operational periods. Overall, this work offers an efficient and sustainable strategy for enhancing AOP performance from PT pathway and advancing PT-dominated AOPs toward practical water decontamination.