Photocatalytic performance of ZnO nanomaterials for self sensitized degradation of malachite green dye under solar light

• ZnO nanomaterials were synthesized by different synthetic methodologies.
• Hydrothermal method creates more surface O2 vacancies in ZnO nanomaterials.
• The correlation between PL and PC activity of ZnO nanomaterials were drawn.
• ZnO nanomaterials exhibit excellent PC activity for photodegradation of MG dye.
• The CO2 evolved due to mineralization of MG was determined by Warburg manometer.

ZnO nanomaterials of different morphologies are synthesized by different methodologies. These semiconductor photocatalysts are potentially explored for self-sensitized photodegradation of malachite green (MG) dye in water in a batch reactor. The effects of various parameters like initial dye concentration, catalyst loading, solution pH, light source on degradation efficiency was also investigated. The experimental results showed substantial reduction of COD, besides removal of colour. The photodegradation of MG dye followed the pseudo first order kinetics of Langmuir–Hinshelwood model. The hydrothermally synthesized flower shaped homocentric pencil like ZnO nanorod bundles exhibit excellent photocatalytic activity under solar light. A comparative study of photodegradation efficiency among ZnO nanoparticles, ZnO nanoparticles (hydrothermal) and flower shaped homocentric pencil like ZnO nanorod bundles were also performed. Semiconductor photocatalysis often leads to partial or complete mineralization of organic pollutants. The CO2 gas evolved due to mineralization of MG was determined using Warburg manometric method under solar light. The possible mechanism of photodegradation under both solar and UV light were also proposed.

ZnO nanomaterials were successfully synthesized and effectively used as photocatalyst for self sensitized photodegradation of malachite green (MG) under solar light. The complete mineralization of MG was confirmed by determining the CO2 production using Warburg manometric method.Figure optionsDownload high-quality image (301 K)Download as PowerPoint slide