Green synthesis strategy for producing doped and undoped ZnO nanoparticles: their photocatalytic studies for industrial dye degradation

Abstract

A facile and green method for synthesizing Zinc Oxide nanoparticles (ZnO NPs) was successfully carried out using unutilized sweet lime; i.e., Citrus Limetta rind pulp (U-CLRP) extract. The structural, morphological and optical studies were elucidated to confirm the crystallinity, size, and shape of the synthesized NPs. Copper doping on ZnO NPs (CZnO NPs) was carried out to enhance the optical properties. The as-prepared and doped nanoparticle's potential for efficient degradation of a commercial dye, Methylene Blue (MB), was tested under Ultraviolet (UV) and visible light radiation. ZnO NPs showed promising results for dye degradation while an improved result was witnessed for CZnO NPs. ZnO NPs showed 74% of degradation of MB dye under UV irradiation and 57% degradation under visible light radiation. CZnO NPs presented 85 and 90% degradation in the UV and visible radiation, respectively. This green reduction method utilizing biological waste sources shows a promising path for photocatalysts to be developed economically as well as efficiently in the future. These CZnO/ ZnO NPs proved their potential for embedding them as efficient catalysts for wastewater treatment plants of textile industries. HIGHLIGHTS Citrus Limetta fruit's unutilized rind pulp extract is utilized for the green synthesis of ZnO NPs.; The extract acted both as a reducing and stabilizing agent.; ZnO and Cu doped ZnO NPs were characterized and tested for their dye degradation potential.; Cu doping on ZnO NPs enhanced its photocatalytic activity under both UV and visible radiation.; This extract paves a green-reduction way for many metal oxide nanostructures.;

Keywords

• copper doping
• green synthesis
• methylene blue dye
• sweet lime rind pulp
• textile industry effluent
• zinc oxide nanoparticles