Sameeksha Rawat, S.M. Tauseef, Madhuben Sharma, Ajay Rautela, Ranjit Gurav
Availability of clean and safe drinking water is a universal issue; hence, the need for advanced water treatment technologies is essential. Nanoparticle-based technologies are extremely promising due to their distinct physicochemical properties and improved performance capabilities. In this article, a comparative assessment of three dominant classes of nanoparticles – metal oxide (TiO 2 , ZnO), carbon-based (carbon nanotubes, graphene), and polymer-based–is presented based on their use in adsorption, catalysis, and filtration processes. These nanomaterials have improved pollutant removal efficiency, targeting a broad spectrum of contaminants such as heavy metals, organic pollutants, and pathogens. Metal oxide nanoparticles exhibit enhanced surface photocatalytic activity, while carbon materials possess high surface area and adsorption. Polymer-based nanoparticles bring in tunability along with flexibility in engineering systems. Although effective and having operationally favourable advantages over traditional approaches, cost-effectiveness, scalability, and environmental friendliness are challenges. Environmental release and hazard risks of nanoparticles, and potential health risks, are matters of severe risk analysis and lifecycle analysis. Synthesis routes should also be optimised in order to decrease the energy use and enhance reuse and stability of the materials. This discussion brings out the revolutionary potential of water treatment technologies involving nanoparticles, but their large-scale use requires addressing the safety, regulation, and economy.