Decoration of Ferrihydrite Nanoparticles on Nitrogen-Doped G-C3n4 for Efficiently Degradation of Tetracycline Through Photocatalytic Activation of Peroxymonosulfate

Abstract

Despite of its contribution to human health, the misuse and substandard discharge of antibiotics can also cause harm to ecosystems and human health. Thus, a novel Fh/N-g-C3N4 composite photocatalyst was prepared by in situ growing of ferrihydrite (Fh) nanoparticles on the surface of nitrogen-doped g-C3N4 (NCN) for activation of peroxymonosulfate (PMS), to efficiently photo-degrade tetracycline, in which the separation and transfer efficiency of photo-generated electron-hole pairs were improved significantly, while their recombination was effectively inhibited. The performance of the Fh/NCN-PMS system in degrading tetracycline under visible light demonstrated that 20%Fh/NCN composite photocatalyst, when coupled with PMS at a concentration of 200 mg/L, resulted in a degradation efficiency of 96.9% for TC at a concentration of 20 mg/L within 30 minutes. Mechanism investigation revealed that 4 main active species (SO4•–, •O2–, 1O2 and h+) were involved in TC degradation, with 1O2 and h+ playing a predominant role. Moreover, the Fh/NCN composited exhibited high and stable catalytic performance to activate PMS under pH 4.5-10, especially the TC degradation efficiency decreased by only 7.1% after four cycles of use. This study provides a new strategy for fabrication of novel photocatalytic-PMS system for efficient treatment of antibiotic wastewater with excellent stability.

Keywords: Ferrihydrite nanoparticles, Antibiotic degradation, Photocatalyst, g-C3N4, Peroxymonosulfate