Highly efficient manganese (III) oxide submerged catalytic ceramic membrane for nonradical degradation of emerging organic compounds

Abstract

In this study the performance of catalytic ceramic membranes in activating peroxymonosulfate (PMS) for the degradation of emerging organic contaminants (EOCs) was investigated. The catalytic ceramic membrane (MnCM) integrated with Mn2O3 nanoparticles was fabricated by a solid-state sintering method. Physical and chemical properties of MnCM were characterized by SEM/EDX, XRD, BET, AFM and XPS. The MnCM/PMS system has shown excellent decontamination efficiencies (81–97% removal) for different EOCs. Acetaminophen (APAP) has been efficiently degraded by MnCM/PMS in different real water matrices and harsh water conditions. Based on results of quenching experiments and electron paramagnetic resonance (EPR) analyses, non-radical pathway with singlet oxygen (1O2) was the dominant ROS for the degradation of EOCs. The membrane pores in active layer acted as micro-reactors for the interaction among active sites, PMS, and EOCs. The MnCM/PMS system showed outstanding catalytic stability with high mineralization (TOC removal of ∼ 65%) and negligible leaching of the manganese (1.3–1.5 µg/L) in permeate. Hydroxylation and C-N bond cleavage were found to be the main degradation pathways of APAP by MnCM/PMS system. The MnCM prepared in this study with excellent performance could be a way forward for applications at large-scale or full-scale water systems suffering from heavy loads or trace amount of refractory organic compounds.