Nanostructured MnOx/g-C3N4 for photodegradation of sulfamethoxazole under visible light irradiation†

The effectiveness of g-C₃N₄ as photocatalyst is hindered by the rapid recombination of photo-generated electron/hole pairs. To improve its photocatalytic performance, the incorporation of g-C₃N₄ with co-catalysts can promote charge separation efficiency and enhance redox capabilities. In our study, a two-step approach involving calcination and solvothermal method was utilized to fabricate a proficient MnO_x/g-C₃N₄ heterojunction photocatalyst with high photocatalytic activity. MnO_x is effective at capturing holes to impede the recombination of electron/hole pairs. The MnO_x/g-C₃N₄ composite shows a notable improvement in photocatalytic degradation of SMX, obtaining an 85% degradation rate, surpassing that of pure g-C₃N₄. Furthermore, the MnO_x/g-C₃N₄ composite exhibits remarkable and enduring catalytic degradation capabilities for sulfamethoxazole (SMX), even after four consecutive reuse cycles. The intermediates produced in the MnO_x/g-C₃N₄ system are found to be less hazardous to common aquatic creatures such as fish, daphnids, and green algae when compared to SMX. With its high tolerance, exceptional degradation ability, and minimal ecological risk, the MnO_x/g-C₃N₄ composite emerges as a promising candidate for eliminating antibiotics from wastewater resources.