Simultaneous degradation of pharmaceutical contaminants and sterilization in real hospital wastewater by a highly efficient electrocatalytic ozonation process: Performance, mechanism and application

Abstract

Herein, this work investigated an electrocatalytic ozonation (ECO) strategy using stainless steel-graphite plates as cathode–anode for the degradation of the pharmaceutical pollutant dexamethasone (DXMS) and the treatment of real hospital wastewater. The reaction kinetic constant of the ECO degradation of DXMS (0.387 min−1) was 4 times higher than that of single ozone (0.087 min−1). The established efficient ECO system successfully degraded pharmaceutical contaminants and had excellent bactericidal effects against pathogenic microorganisms (Escherichia coli). The results of scavenging experiments, chemical probe experiments, and electron paramagnetic resonance (EPR) analysis indicated that the newly generated 1O2 in the ECO system achieved the synergistic effect of the combined EC-ozonation process. More to the point, the ECO system has a high removal rate of chemical oxygen demand (COD) and total organic carbon (TOC) for real hospital wastewater treatment. After 60 min treatment of the ECO system, the COD removal of hospital wastewater ranged from 70 % to 88.91 %, and the TOC removal ranged from 52.05 % to 71.81 %. The ECO system developed in this work has the capacity for simultaneous degradation of pharmaceutical contaminants and sterilization of pathogenic microorganism for hospital wastewater treatment.