Nanomaterials, known for their exceptional physicochemical properties, are used in electronics, skincare, catalysts, agriculture, and water treatment. Their small size and large surface area enable high adsorption capacities and rapid adsorption rates, effectively removing organic and inorganic pollutants from water. Designed as composites, nanomaterials enhance adsorption capacity, improve mechanical strength, and provide support matrices for retaining nanoparticles. Nanoadsorbents are particularly effective in removing toxic metals from wastewater and drinking water, targeting low concentrations of metals like arsenic, cadmium, lead, and mercury, crucial given stringent discharge regulations. However, the widespread use of nanomaterials poses potential health and environmental risks, as their production involves significant energy and material inputs, generating pollutants. Most research focuses on functionalities without considering life cycle environmental impacts. Life cycle assessment (LCA) is a comprehensive tool for evaluating these impacts, assessing products from cradle to grave, including raw material extraction, processing, manufacturing, distribution, use, maintenance, and disposal or recycling. LCA, based on the ISO 14040 series, includes four phases: goal and scope definition, life cycle inventory, life cycle impact assessment, and life cycle interpretation. This study categorizes existing research based on the four LCA phases, aiming to highlight current practices, challenges, and progress. The findings provide insights and recommendations for future research to ensure the sustainable development of nanomaterials.