Synergistic combination of Mn/Fe bimetal-doped carbon nitride and peroxymonosulfate for efficient photocatalytic degradation of antibiotics

Abstract

The widespread of antibiotics has resulted in potential threats to the aquatic environment and human health. The visible light-assisted peroxymonosulfate (PMS) activation method is considered to be an effective way to remove antibiotics in wastewater. In this study, Mn/Fe bimetal doped graphitic carbon nitride (MnFe-CN-x) was first synthesized for PMS activation under visible light towards tetracycline (TC) removal. The optimized MnFe-CN-50 possessed the excellent photocatalytic activity, PMS activation performance and photo-Fenton-like synergistic effect. In the photo-Fenton-like system, TC (20 mg L−1) was degraded by 99 % in 50 min and the kinetic constant was 0.074 min−1. The high dispersion of Mn and Fe in carbon nitride inhibited the recombination of charge carriers in MnFe-CN-x, increased its photocurrent density and charge mobility, effectively optimized the electronic structure, and promoted the generation of 1O2. Based on the analytical results of predictive toxicity evaluation software (TEST), it was confirmed that MnFe-CN-x could effectively reduce the environmental risks associated with antibiotic contamination. This study provided new insights into synthesizing bimetal-doped graphitic carbon nitride and the use of synergistic effects of photocatalysis and PMS activation to remove organic pollutants from wastewater.