Enhanced degradation of levofloxacin using photocatalysis and peroxymonosulfate oxidation processes by Z-scheme BiVO4/ g-C3N4 heterojunction

Constructing a direct Z-scheme heterostructure is an effective way to improve photogenerated charge separation efficiency. In this work, a novel BiVO4/g-C3N4 (BVO/CN) Z-scheme heterojunction was successfully fabricated through a liquid film combustion method and ultrasonic desperation technique. The obtained samples were analyzed by serials characterization techniques, such as XRD, FT-IR, XPS, SEM, HRTEM, EDS, BET, UV-vis, and PL. The results demonstrated a strong integration between CN and BVO, as evidenced by the absorption edge shifting to 520 nm and revealing a narrow band gap (Eg=2.47 eV), thereby enhancing light absorption capacity. Under visible light irradiation, the removal efficiency of levofloxacin (LVFX) reached 97.7 % within 40 min using 20 BVO/CN, which was respectively 2.03 and 2.21 times higher than that achieved with BVO or CN alone. The mechanism of the BVO/CN Z-scheme heterojunction was elucidated based on the ESR test and radical trapping experiment. Additionally, the potential degradation pathway of LVFX was analyzed using HPLC-MS. This study demonstrates the feasibility of constructing a Photocatalyst/Visible-light/peroxymonosulfate (PMS) system for mitigating antibiotic-induced ecological pollution.