Catalytic ceramic nanofiber membrane coupled with ozonation for degradation of sulfamethoxazole: Critical parameters, mechanisms and applicability

Abstract

Catalytic ceramic nanofiber membrane (C-CNM) filtration coupled with catalytic ozonation process was applied for the removal of sulfamethoxazole (SMX) in various water matrix. The C-CNM was made from attapulgite (APT) nanofibers with Mn2O3 nanoparticles anchored on the pits of APT. Up to 89% of SMX was degraded constantly during a 1-h continuous catalytic filtration with the experimental conditions (water flux = 20 LMH, [SMX]0 = 20 mg/L, [O3 (aq)]inf = 10.5 mg/L). The effects of permeate flux, membrane layer thickness, and the presence of co-existing ions and HA on the degradation efficiency of SMX by C-CNM filtration coupled with catalytic ozonation were studied. The results shows that the degradation of SMX occurred primarily in the membrane layer and the SMX removal increased with smaller fluxes and thicker membrane layer. Besides, the presence of Cl− and H2PO4− ions obviously inhibited SMX removal while the presence of HCO3– slightly enhanced SMX removal. The reactive oxygen species (ROS) that contributed to the removal of SMX were identified to be 1O2, ·OH and O2·− by electron paramagnetic resonance (EPR) analysis and quenching experiments. More importantly, C-CNM/ozone filtration system demonstrated wide applicability for the treatment of a variety of emerging organic contaminants and high removal efficiency of SMX even in real waters. This work promotes the engineering application of catalytic ceramic membrane coupling with advanced oxidation in the decontamination of emerging organic contaminants from water and wastewater.