Enhanced photocatalytic degradation of methylene blue dye by ZnO nanoparticles: Synthesis, characterization, and efficiency assessment

Abstract

The release of synthetic dyes from the textile industry into aquatic environments poses a significant threat due to their carcinogenic properties. Photocatalytic treatment methods have emerged as efficient alternatives for addressing dye contamination in water. In this study, we investigate the photocatalytic degradation of methylene blue dye using zinc oxide (ZnO) nanoparticles under UV irradiation. ZnO nanopowders were synthesized via the sol–gel process and characterized for their structural, optoelectronic, optical, and chemical properties to demonstrate their suitability for photocatalytic degradation. Photocatalytic experiments were conducted using pure ZnO nanoparticles as catalysts, resulting in a degradation efficiency of 72.3% for methylene blue. Characterization techniques, such as X-Ray Diffraction (XRD), Energy Dispersive X-Ray Analysis (EDX), Scanning Electron Microscopy (SEM), and FTIR confirmed the presence of ZnO bonds and the uniform distribution of nanoparticles with small grain sizes. Density Functional Theory (DFT) calculations using the modified Becke–Johnson (mBJ) approximation revealed a direct band gap of 3 eV for ZnO, confirming its potential for photocatalysis. These findings underscore the enhanced photocatalytic activity of ZnO nanoparticles, highlighting their potential for use in photocatalysis applications. This study contributes to the growing body of research aimed at addressing environmental challenges associated with dye contamination in water.