NANOTECHNOLOGY AND ADVANCED MATERIALS FOR ENVIRONMENTAL SUSTAINABILITY ACROSS WATER TREATMENT, AIR QUALITY, AND GREEN ENERGY TECHNOLOGIES

Abstract

The accelerating deterioration of environmental quality coupled with escalating global energy demands has created an urgent need for innovative, sustainable technological solutions. Nanotechnology, operating at the atomic and molecular scale, offers unprecedented opportunities to address these intertwined challenges through engineered materials with exceptional physicochemical properties. This comprehensive review critically examines recent advances in nanomaterial and nanotechnology-enabled processes for water treatment, air quality management, and green energy technologies. Nanostructured materials including noble metal nanoparticles (Ag, Au), transition metal oxides (TiO₂, ZnO, Fe₃O₄), carbon-based nanomaterials (carbon nanotubes, graphene, graphene oxide), and their multifunctional nanocomposites demonstrate remarkable efficacy in pollutant removal, contaminant sensing, and energy conversion. In water remediation, these materials function through adsorption, photocatalysis, nanofiltration, and disinfection, achieving complete mineralization of organic pollutants and near-total removal of heavy metals and pathogens. For air quality, nanomaterials enable high-efficiency particulate filtration, catalytic conversion of NOₓ, SO₂, and VOCs, and real-time monitoring via nano sensors. In the green energy sector, nanotechnology enhances photovoltaic efficiency, improves battery and supercapacitor performance, facilitates photocatalytic hydrogen production, and optimizes biofuel generation. The review also critically addresses nanomaterial toxicity, environmental fate, life cycle assessment, and the principles of green nanotechnology for sustainable implementation. Despite remarkable progress, challenges persist regarding large-scale production, cost-effectiveness, regulatory frameworks, and long-term ecological impacts. This synthesis provides a foundational resource for researchers, environmental engineers, and policymakers working toward nanotechnology-driven environmental sustainability.