Optimização da degradação fotocatalítica do levofloxacino através da heteroestrutura de Bi2WO6/CuO

Abstract

The improper disposal of pharmaceutical waste containing antibiotics contaminates aquatic systems, promoting the emergence of antibiotic-resistant superbugs. Heterogeneous photocatalysis (HP) and binary heterostructures emerge as promising strategies to efficiently degrade these contaminants. In this study, a CuO nanosheets structure was decorated with Bi2WO6 nanoflower to form Bi2WO6/CuO n-p heterostructures through a simple two-step process using a microwave-assisted hydrothermal approach (MWHA). The synthesized photocatalysts were evaluated through the degradation of the antibiotic levofloxacin as the target pollutant under solar irradiation. The optical properties and structural morphology of the BWO/CuO photocatalysts were demonstrated. The XRD and FT-IR results corroborate, indicating the crystallinity and purity of the samples obtained by MWHA. The X-ray diffractograms showed the presence of crystalline phases of orthorhombic β-Bi2WO6 and monoclinic β-CuO, with no secondary phases. The FEG-SEM images of the heterostructures revealed a morphology resembling a three-dimensional flower with aggregated nanosheets, which are derived from the pure samples. BET analyses indicated that the BW/Cu-10 sample has the largest surface area among the heterostructures, which explains its superior photocatalytic performance. The degradation of levofloxacin by BW/Cu-10 achieved 95% efficiency in 120 minutes. The enhanced photocatalytic abilities of the BWO/CuO heterostructures were attributed to the construction of an np heterojunction, effective charge separation according to the n-p type mechanism, and prolonged carrier lifetime, which efficiently suppressed the recombination of photoinduced electron/hole pairs. The obtained BWO/CuO heterostructures were stable over four consecutive cycles with almost constant degradation capacity. Therefore, due to their promising photocatalytic abilities, BWO/CuO are suitable photocatalysts for environmental treatment applications.