A comprehensive review: Photodegradation of dyes with rare earth doped metal oxide nanoparticles for wastewater treatment

Abstract

Photocatalytic degradation of organic dyes is one of the most important techniques to eliminate dyes from wastewater from industrial effluent. Since organic dyes are poisonous, carcinogenic, and resistant to standard treatment techniques, they pose a serious threat to human health and the environment. Their continued presence in aquatic environments endangers human health by lowering water quality and upsetting aquatic life. The technique of photodegradation of dyes has the potential to significantly improve wastewater treatment's sustainability, economy, and efficiency, which would be extremely beneficial to the environment and public health. This comprehensive review focuses on the applications of rare earth-doped metal oxide nanoparticles as highly effective photocatalysts for dye degradation under UV–visible light irradiation. Rare earth dopants enhance visible light absorption, improve charge separation, and facilitate the generation of reactive oxygen species that drive the oxidative degradation of dye molecules. Synthesis methods including sol-gel, hydrothermal, and plant-mediated approaches for producing rare earth-doped nanoparticles are outlined. Key factors affecting the efficiency of photodegradation, including pH levels, catalyst concentration, temperature, duration, and initial dye concentration, are analyzed. The review elucidates the mechanisms underlying the pathways of photocatalytic dye degradation facilitated by rare earth dopants. A comparative assessment underscores the superior performance of rare earth-doped nanoparticles over their non-doped counterparts across a diverse array of dyes. These nanoparticles present a promising and sustainable avenue for efficient wastewater treatment by enhancing the photocatalytic breakdown of organic dye pollutants. In the broader context of sustainable chemical production, rare earth-doped nanoparticles not only contribute to environmental protection but also align with green chemistry principles by reducing the need for harsh chemicals and minimizing energy consumption during catalytic processes. Furthermore, their potential for integration into larger-scale chemical production systems paves the way for innovative materials that can drive eco-friendly industrial processes. Lastly, prospects encompassing further refinement of nanoparticle structures, upscaling of production, and deeper insights into mechanisms are explored to advance rare earth-doped nanoparticles as sustainable and economically viable solutions for wastewater dye remediation and beyond, contributing to the circular economy and sustainable chemical production.