A Nanoconfined FeCo<sub>2</sub>O<sub>4</sub>-Embedded Ceramic Membrane Regulates Electron Transfer in Peroxymonosulfate Activation to Selectively Generate Singlet Oxygen for Water Decontamination
Peng Xu, Rui Wei, Peng Wang, Tianyao Shen, Tong Zheng, Guangshan Zhang
Abstract
Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs), as a promising technology for water decontamination, are constrained by low reaction kinetics due to limited reaction selectivity and mass transfer. Herein, we designed a nanoconfined FeCo 2 O 4 -embedded ceramic membrane (FeCo 2 O 4 −CM) under flow-through pattern for PMS activation. Confining PMS and FeCo 2 O 4 within nanochannels (3.0−4.7 nm) enhanced adsorption interactions (−7.84 eV vs −2.20 eV), thus boosting mass transfer. Nanoconfinement effect regulated electron transfer pathways from PMS to FeCo 2 O 4 −CM by modulating the active site transformation to ≡Co(III) in nanoconfined FeCo 2 O 4 −CM, enabling selectively generating 1 O 2 . The primary role of 1 O 2 in the nanoconfined system was confirmed by kinetic solvent isotope experiments and indicative anthracene endoperoxide (DPAO 2 ). The system enabled 100% removal of atrazine (ATZ) within a hydraulic retention time of 2.124 ms, demonstrating a rate constant over 5 orders of magnitude higher than the nonconfined system (3.50 × 10 3 s −1 vs 0.42 min −1 ). It also exhibited strong resilience to pH variations (3.3−9.0) and coexisting substances, demonstrating excellent stability indicated by consistent 100% ATZ removal for 14 days. This study sheds light on regulating electron transfer pathways to selectively generate 1 O 2 through the nanoconfinement effect, boosting the practical application of PMS-based AOPs in environmental remediation and potentially applying them to various other AOPs.