Efficient degradation of ciprofloxacin in water using nZVI/g-C₃N₄ enhanced dielectric barrier discharge plasma...

Residual antibiotics in aquatic environments pose health and ecological risks due to their persistence and resistance to biodegradation. Thus, it is crucial to develop efficient technologies for the degradation of such antibiotics. This study presents a novel approach using a nano zero-valent iron/graphitic carbon nitride (nZVI/g-C₃N₄)-enhanced dielectric barrier discharge (DBD) plasma process for the degradation of ciprofloxacin (CIP). The combination of nZVI and g-C₃N₄ with DBD plasma significantly enhances CIP degradation efficiency, achieving an apparent first-order kinetic constant of 0.2849 min⁻¹ at an input voltage of 12 kV, which is 5.22 times higher than standalone DBD treatment and 10.59 times higher than the ozonation treatment. The morphology, elemental valence states, and other properties of nZVI/g-C₃N₄ have been thoroughly characterized and demonstrate good reusability. Reactive species such as ·OH dominates CIP degradation. The Fe atoms in nZVI/g-C₃N₄ exhibit a strong tendency to donate electrons, generating reactive oxygen through the dissociation of adsorbed water. The cleavage of C-F bonds, hydroxylation and ring-opening oxidation of the piperazine group are the main pathways for CIP degradation, which helps to reduce biotoxicity after treatment. Overall, this study provides insights into the mechanism of reactive species in a DBD-nZVI/g-C₃N₄ system, a system that has the potential to become an efficient and environmentally friendly solution for the treatment of antibiotic wastewater.