The presence of trace levels of antibiotics in drinking water poses a serious concern as it contributes to the development of antibiotic resistance in bacteria. In this study, various bismuth-based ternary heterostructure photocatalysts were synthesized by combining BiOX/Bi 2 WO 6 (where X = Cl, Br, or I) heterostructures with Bi 2 S 3 at a molar ratio of 1:1:1. The X-ray deffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the successful synthesis of BiOX/Bi 2 WO 6 /Bi 2 S 3 ternary heterostructures with tunable band gaps, while the photoluminescence (PL) spectroscopy indicated enhanced charge separation. The photocatalytic performance of these ternary heterostructures was evaluated by degrading ciprofloxacin (CFX) in an aqueous solution under solar light. All the ternary heterostructures, namely BiOCl/Bi 2 S 3 /Bi 2 WO 6 (BWS-Cl), BiOBr/Bi 2 S 3 /Bi 2 WO 6 (BWS-Br), and BiOI/Bi 2 S 3 /Bi 2 WO 6 (BWS-I), demonstrated excellent photodegradation of CFX within 120 min. The degradation rate constant (k) for CFX using the BWS-Cl heterostructure was 0.023 min⁻¹. The effect of catalyst dosage, CFX concentration, and the initial pH of the drug solution on the photocatalytic degradation performance of CFX was also examined. Notably, the BWS-Cl exhibited the highest degradation efficiency at 96.6%, achieved under sunlight with an optimized catalyst dosage of 0.6 g/L and an initial ciprofloxacin concentration of 5 ppm at a pH of 9.00. Based on the results from radical trapping experiments and PL analysis, a potential degradation mechanism for CFX by these heterostructures was proposed. The stable and reusable ternary heterostructure photocatalysts developed in this work may find applications in the removal of CFX and other similar emerging organic pollutants from potable water. • Synthesized BiOX/Bi 2 WO 6 /Bi 2 S 3 heterostructures for visible-light photocatalysis • The heterojunctions showed excellent visible-light photodegradation of CFX • The ternary BiOX/Bi 2 WO 6 /Bi 2 S 3 heterojunctions showed stability and reusability • The synthesized heterojunctions showed enhanced charge separation • Holes and superoxide radicals played dominant roles in photodegradation
Naeem et al. (Tue,) studied this question.