Peroxymonosulfate activation on a chainmail catalyst via an electron shuttle mechanism for efficient organic pollutant removal

Abstract

We present a chainmail catalyst (N-doped carbon nanotube-confined FeMn nanoparticles, FeMn@NCNT) for activation of peroxymonosulfate (PMS) to eliminate organic micropollutants (OMPs). Complete removal of 50 μM 4-chlorophenol (4-CP) was achieved in 7 min. Radical quenching tests and electron paramagnetic resonance suggested that an electron transfer process (ETP) dominated the degradation of pollutants, while •OH and •SO4- were the secondary oxidants. In an upgraded galvanic oxidation system, the surge of current and the decrease of in-situ cathode potential after adding 4-CP indicated the electron shuttle rather than adjacent transfer mechanism dominated ETP. A novel spray-crosslinking method was introduced to deposit powder FeMn@NCNT on a commercial ceramic membrane. The coated membrane exhibited a negligible decrease of water flux, excellent mechanical stability and outstanding OMP elimination performance. This study provides new insights into ETP and advances the application of powder catalysts in combined filtration/oxidation water treatment processes.