Removal of tetracycline by ultraviolet/sodium percarbonate (UV/SPC)advanced oxidation process in water

Tetracycline (TC) was widely used and frequently detected in various water bodies, where the presence of TC posed a significant threat to the health of aquatic organisms. Furthermore, antibiotics were hardly degraded by biological treatment. Thus, in order to enhance the removal of TC, we proposed the use of a novel ultraviolet/sodium percarbonate (UV/SPC) advanced oxidation process and initiated an in-depth study. The study investigated the influence of oxidant dosage, initial pH, UV intensity, and TC concentration on the removal of TC. The results demonstrated that the UV/SPC system efficiently removed TC, with removal efficiency increasing as the SPC concentration increased. Within the pH range of 3-11, TC degradation exhibited minimal variation, indicating the UV/SPC system's strong adaptability to pH variations. The research on the impact of the water matrix on TC removal revealed that HCO₃^- had an inhibitory effect on TC degradation, while NO₃^- promoted TC degradation. Additionally, the presence of free radical species (·OH, ·CO₃^-, ·O₂^-) were detected and rate constants for the secondary reactions (k_·OH,TC = 6.3 × 10⁹ L mol^-1·s^-1, k_·CO3-,TC = 3.4 × 10⁸ L mol^-1·s^-1) were calculated, indicating that ·OH exhibited a stronger oxidative performance compared to ·CO₃^-. This study did not only present a novel strategy via UV/SPC to remove TC but also uncovered the unique role of ·CO₃^- for contaminant removal.