Introduction Water pollution is considered one of the most serious environmental challenges facing the world today, as a result of rapid industrial expansion and accelerated population growth. These factors have led to the deterioration of water quality and increased the demand for advanced and effective technologies for water treatment. Among these modern approaches, nanochemistry has emerged as a promising solution in the field of drinking water purification and contaminated water treatment, due to the unique properties of nanomaterials at the atomic and molecular levels. Concept of Nanochemistry in Water Treatment Nanochemistry in water purification focuses on the study and synthesis of nanomaterials with high efficiency in removing physical, chemical, and biological contaminants from water. These materials are characterized by a large surface area and high chemical reactivity, making them more effective than conventional materials used in traditional water treatment systems. Types of Nanomaterials Used in Water Purification Nanomaterials employed in this field include: Metallic nanoparticles, such as iron oxide and titanium dioxide, which possess a high capacity for contaminant adsorption and catalytic activity. Carbon nanotubes and graphene, which are used in nanomembranes to remove salts and organic pollutants. Magnetic nanoparticles, which facilitate the separation of contaminants from water using an external magnetic field. Nanocatalysts, applied in the degradation of toxic organic compounds. Mechanisms of Water Purification Using Nanomaterials Nanochemistry relies on several key mechanisms for water purification, including: Adsorption, for the removal of heavy metals and organic pollutants. Photocatalysis, which decomposes organic contaminants using solar or artificial light. Nanofiltration membranes, for the removal of salts, microorganisms, and suspended particles. Reductive chemical reactions, used to neutralize or remove toxic substances. Applications of Nanochemistry in Water Purification Nanotechnology-based techniques have demonstrated high efficiency in: Removing heavy metals such as lead, mercury, and cadmium. Eliminating bacteria and viruses. Desalinating saline water and seawater. Treating industrial and agricultural wastewater. Nanochemistry and Drinking Water Safety Despite the significant advantages of nanotechnology in water treatment, the safety of using nanomaterials in drinking water remains under continuous investigation. Therefore, recent research focuses on developing safe, non-toxic, and recoverable nanomaterials to ensure the protection of human health and the environment. Challenges and Future Perspectives The main challenges associated with nanochemistry include the high cost of some nanomaterials and the difficulty of assessing their long-term environmental impact. Nevertheless, ongoing advancements in nanochemistry are expected to reduce costs and enhance the efficiency of water treatment systems in the future. Conclusion Nanochemistry represents one of the most advanced scientific solutions to water pollution problems, offering effective and sustainable technologies for water purification and quality improvement. This field is expected to play a pivotal role in achieving water security and supporting sustainable development in the coming years.