This review discusses recent advancements in nanoparticle and nanocomposite technologies for water and wastewater treatment. Nanoparticles and nanocomposites offer efficient solutions for removing contaminants from water due to their high surface area, reactivity, and unique properties. The review covers various types of nanoparticles, including metal nanoparticles, carbon-based nanomaterials, and hybrid nanocomposites, and their applications in water treatment. It also explores the mechanisms of pollutant removal, such as adsorption, catalysis, and membrane filtration, and the environmental implications of using these materials. The review highlights the effectiveness of nanomaterials in removing heavy metals, organic pollutants, and pathogens from water. It also discusses challenges associated with the widespread use of nanomaterials, such as toxicity and the need for efficient recovery methods. The review emphasizes the potential of nanoparticles and nanocomposites in addressing water-related challenges and suggests future research directions for improving water treatment technologies. Key nanomaterials discussed include iron oxide, silver, titanium dioxide, zinc oxide, copper, and carbon-based nanomaterials, each with unique properties and applications in water treatment. The review concludes that nanotechnology offers promising solutions for water and wastewater treatment, but further research is needed to address challenges and optimize their use.This review discusses recent advancements in nanoparticle and nanocomposite technologies for water and wastewater treatment. Nanoparticles and nanocomposites offer efficient solutions for removing contaminants from water due to their high surface area, reactivity, and unique properties. The review covers various types of nanoparticles, including metal nanoparticles, carbon-based nanomaterials, and hybrid nanocomposites, and their applications in water treatment. It also explores the mechanisms of pollutant removal, such as adsorption, catalysis, and membrane filtration, and the environmental implications of using these materials. The review highlights the effectiveness of nanomaterials in removing heavy metals, organic pollutants, and pathogens from water. It also discusses challenges associated with the widespread use of nanomaterials, such as toxicity and the need for efficient recovery methods. The review emphasizes the potential of nanoparticles and nanocomposites in addressing water-related challenges and suggests future research directions for improving water treatment technologies. Key nanomaterials discussed include iron oxide, silver, titanium dioxide, zinc oxide, copper, and carbon-based nanomaterials, each with unique properties and applications in water treatment. The review concludes that nanotechnology offers promising solutions for water and wastewater treatment, but further research is needed to address challenges and optimize their use.