Construction and application of BiOCl/Cu-doped Bi2S3 composites for highly efficient photocatalytic degradation of ciprofloxacin

In this work, a novel BiOCl/Cu-doped Bi2S3 photocatalyst was designed to efficiently remove ciprofloxacin (CIP) with high photocatalytical activity and good stability over a wide pH range. Compared with Cu-doped Bi2S3, Bi2S3, BiOCl, BiOCl/Bi2S3, and Cu-doped BiOCl, the photocatalytical degradation rate of CIP (97.1% at 20 mg/L) over BiOCl/Cu-doped Bi2S3 was enhanced by about 84.77, 44.23, 2.95, 2.27, and 1.96 times within 20 min, respectively. Notably, the BiOCl/Cu-doped Bi2S3 photocatalyst also displayed high photocatalytical performance in the degradation of other antibiotics including norfloxacin, ofloxacin, and tetracycline (40 mL, 20 mg/L; 88.3%, 100%, and 95.2% of degradation rate within 30 min, respectively) under visible light irradiation. Radical trapping experiments and electron spin resonance technique indicated that superoxide radicals (•O2-) and photogenerated holes (h+) played crucial roles in the photocatalytic degradation of CIP. Finally, the possible CIP degradation pathways was proposed by detecting the CIP intermediates in photocatalytical reaction process.