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

Abstract

Newly molding g‐C3N4/graphitized biochar (g‐C3N4/GSBC) molding composites photocatalytic material with superior photocatalytic activity were successfully synthesized by the impregnation‐roasting process. The photocatalytic behavior of g‐C3N4/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‐C3N4 with GSBC was demonstrated by various characterization results, in which the 5 : 1 mass loading ratio showed the best performance. g‐C3N4/GSBC possessed a larger specific surface area (71.09 m2/g), suitable band gap (2.66 eV), more catalytically active species, and higher utilization efficiency of visible light than powdered g‐C3N4. The removal efficiency of the new composite was higher than that of g‐C3N4 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 ⋅O2− 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.