Efficient dye degradation strategies using green synthesized ZnO-based nanoplatforms: A review

Organic pollutants in industrial waste must be handled with viable and eco-friendly approaches. In particular, releasing toxic effluents like dyes into the environment pollutes water bodies, causing fatal diseases in humans and is hazardous to aquatic life. It necessitates the removal of effluent dyes before being discharged into the water bodies. The photocatalytic degradation method using metal oxide nanoparticles is the preferred choice amongst various dye remediation strategies. However, state-of-the-art metal oxide nanoparticle-based dye remediation involves developing non-toxic, economic, and eco-friendly metal oxides using green chemistry. Plant-mediated ZnO-based nanoplatforms exhibited substantial photocatalytic properties, non-toxicity, biocompatibility, and cost-effectiveness, possessing the potential to replace conventional dye remediation strategies. This review focuses on the development and performance of green synthesized ZnO nanoparticles towards degrading various dyes for wastewater remediation. It comprehensively summarizes the state-of-the-art green ZnO nanoparticle fabrication from various plant extracts (like leaves, seeds, juice, and fruits), illustrates their dye removal efficacies, and details their photocatalytic dye degradation mechanism. This review aims to serve as a fundamental structure to guide future research on green ZnO-based nanoplatforms for wastewater treatment, where photocatalytic attributes and green chemistry are prerequisites.