Synthesis and Optimization of Visible-light-driven G-C₃N₄/CoMoO₄ for the Removal of Tetracycline

Abstract

Nowadays, antibiotic residue in the aqueous environment is a critical issue that causes serious effects on human and ecological health. While the conventional treatment approaches cannot completely remove them from wastewater, photocatalytic materials have recently emerged as a promising strategy for antibiotic removal. Among them, graphitic carbon nitride (g-C₃N₄) has received great attention due to its metal-free, non-toxic, low-cost, and environmentally friendly characteristics. However, the photocatalytic efficiency of g-C₃N₄ is limited by its high charge carrier recombination rate. In this research, a heterojunction photocatalyst of g-C₃N₄/CoMoO₄ was synthesized by a hydrothermal-calcination method. The effect of g-C₃N₄/CoMoO₄ mass ratio, hydrothermal conditions, calcination conditions, pH, pollutant, and catalyst dose on photocatalytic degradation of tetracycline was investigated. The synthesized photocatalyst was characterized by scanning electron microscopy − energy dispersive X-ray (SEM-EDX), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The results showed that the composite photocatalyst synthesized with a 6:4 mass ratio of g-C₃N₄:CoMoO₄ for 6 h of hydrothermal treatment and calcination temperature of 500°C showed the highest removal efficiency of tetracycline at pH = 7.