Visible light-driven photocatalytic degradation of norfloxacin by biochar-supported Cs3Bi2I9-Bi2MoO6 Z-scheme composite: Characterization, optimization, and toxicity assessment
Аннотация
Photocatalytic degradation presents a promising strategy for mitigating global water pollution by effectively breaking down persistent organic contaminants into harmless byproducts. Herein, a novel biochar-supported Cs 3 Bi 2 I 9 -Bi 2 MoO 6 composite was synthesized via a combination of simple impregnation and ultrasonic methods for the photocatalytic degradation of norfloxacin (NOR), a persistent pharmaceutical contaminant in water systems. The composite was characterized using XRD, XPS, Raman, SEM, TEM, BET, and UV–vis DRS to assess its structural and optical properties. The photocatalytic activity was optimized through Response Surface Methodology (RSM) and Central Composite Design (CCD), systematically exploring key variables such as catalyst dose, Temperature, pH, and NOR concentration. The ANOVA analysis showed the model was significant (F = 42.04, p < 0.0001). The quadratic model, with adjusted R 2 of 0.957 and predicted R 2 of 0.883, demonstrated strong fit and predictive accuracy. Under optimal conditions, the composite achieved a degradation efficiency of 95.6 % within 75 min. Also, Electrochemical and optical analyses, including EIS, photocurrent, UV–vis, and PL revealed the critical role of biochar in enhancing photocatalytic activity by improving charge separation and light absorption, ultimately boosting the overall degradation efficiency. Radical scavenging experiments and ESR analysis confirmed the involvement of OH and O 2 − radicals in the degradation process. This study highlights the potential of Biochar-supported Cs 3 Bi 2 I 9 -Bi 2 MoO 6 as an efficient and stable photocatalyst for environmental remediation, demonstrating excellent reusability with consistent performance over five consecutive cycles. • A novel biochar-supported Cs 3 Bi 2 I 9 -Bi 2 MoO 6 Z-Scheme photocatalyst was synthesized for the first time. • The composite achieved 95.6 % degradation efficiency of norfloxacin (NOR) within 75 min. • Biochar enhanced the photocatalytic performance by improving electron-hole separation. • Trapping experiments confirmed that OH and O 2 − radicals played crucial roles in NOR degradation. • The composite exhibited excellent reusability, maintaining high efficiency after five cycles.