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.