Effective removal of emerging organic pollutants using hybrid Ag@ZnO supported reduced-graphene oxide nanocomposite under visible light

Abstract

The present study successfully synthesized a rGO-modified Ag@ZnO nanocomposite using simple aqueous solution reactions conducted at low temperatures that successfully removed five emerging pollutants including nonylphenol, roxarsone, ciprofloxacin, rhodamine B, and methylene blue under visible light illumination. A comprehensive analysis encompassing the material optical properties, structure, chemical and surface characteristics was performed, revealing the presence of Ag@ZnO nanoparticles uniformly dispersed on reduced Graphene Oxide (rGO) layers, with particle sizes ranging from 100 to 200 nm. Important features include the material's high purity and a substantial surface area of 636.42 m2/g. The Ag@ZnO@rGO nanocomposite demonstrated significant efficacy of all the mentioned pollutants, achieving an effective removal rate exceeding 85 % after approximately 4 h of visible light irradiation. Systematic optimization of key process parameters, including catalyst dosage, methylene blue (MB) concentration, and pH levels, was performed. Further investigation into MB removal efficiency, using different scavengers, elucidated the crucial role of O2- during photodegradation, providing insightful mechanistic details. Significantly, sustained efficiency over five cycles underlined the reliability of this nanostructure composite.

Keywords

• Ag@ZnO@rGO
• Emerging pollutants
• Degradation
• Visible light
• Efficiency