Enhanced photocatalytic decolorization of Congo red dye with surface-modified zinc oxide using copper(II)–amino acid complex

Abstract

Photocatalytic decolorization of Congo red dye has been investigated using surface-modified ZnO nanoparticles by adsorbing copper(glycinato) complex on the surface of nanosized ZnO. The complex-adsorbed photocatalyst is shown to exhibit enhanced photodecolorization of the dye compared to the pure ZnO nanoparticles. Effect of catalyst dose, initial dye concentration, and role of H₂O₂ as oxidizing agent has been studied in order to optimize the condition for efficient decolorization. The nanosized ZnO was prepared by precipitation method onto which the amino acid complex was adsorbed. The synthesized catalysts were characterized by XRD, UV, FTIR, SEM, and EDAX. Comparative evaluation of photodecolorization of the dye was investigated for both the nanosized ZnO and the complex-adsorbed ZnO nanoparticles under optimized conditions.

Keywords:

• Congo red dye
• copper–amino acid complex
• nanosized ZnO
• photodecolorization
• surface modification