Water scarcity and the demand for potable water are affecting people globally, particularly in developing nations with growing populations. Annually, numerous contaminants such as dyes, heavy metals, pesticides, microorganisms, and hydrocarbons adversely affect aquatic life and ecosystems, rendering the water unfit for human consumption. Innovations in water treatment technology have emerged to address the scarcity of accessible water and the rising levels of contamination. Adsorption is crucial for environmental restoration and has attracted significant attention in both scientific research and industrial applications. The field of environmental nanotechnology has advanced rapidly in recent years, driven by the swift growth of nanotechnology and the development of nanomaterials. Nanoscale materials are attracting considerable attention in worldwide development efforts because of their distinctive characteristics. Their nanoscale dimensions have led to improved catalysis, heightened receptivity, and augmented adsorption capabilities. Metal oxide nanoparticles like titanium dioxide (TiO₂), zinc oxide (ZnO), and iron oxide (Fe₃O₄) exhibit remarkable adsorption capabilities, rendering them particularly efficient in the elimination of heavy metals, organic pollutants, and microbial contaminants from water. The application of nanotechnology in wastewater management represents a significant commitment to enhancing the efficiency and effectiveness of water purification, offering a sustainable approach to protecting water resources. This review examines the fundamental concepts and stages of the absorption process, along with the most recent findings on nanomaterials, including carbonaceous nanomaterials, metal-containing nanoparticles, and nanocomposites.