Visible‐light‐driven photocatalytic degradation of antibiotics by newly molding g‐C3N4/graphitized biochar composites

Abstract Newly molding g‐C 3 N 4 /graphitized biochar (g‐C 3 N 4 /GSBC) molding composites photocatalytic material with superior photocatalytic activity were successfully synthesized by the impregnation‐roasting process. The photocatalytic behavior of g‐C 3 N 4 /GSBC was assessed in the photocatalytic degradation of antibiotic pollutants, including sulfamethoxazole(SMZ), ciprofloxacin(CIP), and tetracycline(TC), under visible light illumination. The successful composited of g‐C 3 N 4 with GSBC was demonstrated by various characterization results, in which the 5 : 1 mass loading ratio showed the best performance. g‐C 3 N 4 /GSBC possessed a larger specific surface area (71.09 m 2 /g), suitable band gap (2.66 eV), more catalytically active species, and higher utilization efficiency of visible light than powdered g‐C 3 N 4 . The removal efficiency of the new composite was higher than that of g‐C 3 N 4 for the three antibiotics, with removal efficiencies of 87.2 %, 83.2 %, and 72.2 % for SMZ, TC, and CIP, respectively. The analysis of its photodegradation mechanism revealed that h + and ⋅O 2 − are responsible for the antibiotics′ decomposition. According to the HPLC‐MS results, the possible photocatalytic mechanism and reaction pathways have been proposed. This work provided a new way for the synthesis of molding photocatalysts as an efficient photocatalyst for the degradation of organic contaminants.