PHOTOCATALYTIC DEGRADATION OF ANIONIC AND CATIONIC DYES BY Bi₂WO₆/ZnO NANOCOMPOSITE UNDER VISIBLE LIGHT IRRADIATION AND STUDY OF ITS ANTIMICROBIAL ACTIVITY

This study investigates the synthesis and performance evaluation of a visible light-driven photocatalyst, Bi₂WO₆/ZnO, for degrading industrial sewage dyes and its antimicrobial activity. The novel Bi₂WO₆/ZnO composite was synthesized via a hydrothermal method and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). XRD analysis confirmed the presence of diffraction peaks corresponding to Bi₂WO₆ and ZnO, indicating high purity and crystallinity. FTIR analysis validated the chemical bonds of Bi₂WO₆ and ZnO in the composite material. TEM analysis revealed nanoparticle sizes of approximately 46 nm, corroborating the XRD results. Additionally, selected-area electron diffraction (SAED) patterns supported the crystalline nature of the composite.

The photocatalytic efficiency of Bi₂WO₆/ZnO was evaluated by degrading cationic (RhB, MB, CV, ) and anionic (EY, EB) dyes under visible light exposure for 90 minutes. Kinetic studies demonstrated high degradation efficiencies for cationic dyes, achieving impressive removal rates of RhB (97%), MB (96%), and CV (88%) within the specified timeframe. Anionic dyes exhibited slightly lower degradation percentages, with EY and EB being degraded by 62% and 69%, respectively. Moreover, the composite showed significant antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans, highlighting its potential for antimicrobial applications.

Further investigations were conducted to assess the effect of varying the dosage of Bi₂WO₆/ZnO photocatalyst on degradation efficiency, focusing on RhB and MB dyes. Experiments ranging from 0.1 g/L to 0.5 g/L determined the optimal dosage for degradation to be 0.4 g/L for both dyes. Remarkably, the photocatalyst maintained high efficiency even after five cycles, showcasing its structural stability and reusability.

In conclusion, the synthesized Bi₂WO₆/ZnO composite demonstrates promising potential as an effective photocatalyst for dye degradation as well as antimicrobial activity.