Advances in wastewater remediation using functionalized metallic and semiconductor nanomaterials: A systematic review

The increasing scarcity of water resources has driven the need for innovative solutions for wastewater reclamation using different nanomaterials. The purpose of the research was to establish the progress of wastewater remediation using functionalized metallic and semiconductor nanomaterials. A systematic review was carried out following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodology with a search comprised between the years 2010 to 2024, from which 50 scientific articles were selected that met inclusion and exclusion criteria. Magnetic, noble, and chalcogenide metallic nanomaterials, as well as semiconductor nanoma-terials, were considered. As an advance it was reported that the most efficient nanomaterial in the recovery of contaminated water is ZnO that when functionalized has high adsorption capacity of several heavy metals ions (Cd²⁺, Hg²⁺ and Pb²⁺), being reusable for several cycles; for its part, functionalized CuO is highly efficient in the adsorp-tion of Ni²⁺ and Cd²⁺ having an efficiency of 99.16%; another advance found is the use of magnetic nanoparticles Fe₃ O₄ and Fe₂ O₃ for specific adsorption of heavy metal ions with efficiencies above 99%, and with significant re-usability with magnetic desorption methods; for adsorption of dyes and colorants the compound CoFe₂O₄ reaches efficiencies of 98.6% for methylene blue and 95.3% for rhodamine B; semiconducting nanomaterials such as TiO₂ stand out in the degradation of organic pollutants by photocatalysis, managing to remove up to 95% of dyes and pesticides; finally, advanced functionalization techniques, such as the use of L-cysteine in Au nanoparticles, have enabled the rapid detection of heavy metals through color changes in plasmons. It is concluded that these advances not only improve efficiency in the remediation of water contaminated by heavy metals, dyes, colorants, and organic and inorganic pollutants in general but also promote sustainability through the repeated use of nanomaterials, which reduces costs and minimizes environmental impact.