Nanotechnology for Radionuclide and Heavy Metal Removal in Mining-Impacted Water Systems: Advances, Challenges, and Future Directions

Abstract

Mining activities release radionuclides and toxic heavy metals into aquatic systems, creating long-term risks to water quality, ecosystems, and human health. Conventional remediation technologies often show limited effectiveness in mining-impacted waters due to complex geochemical conditions, including high salinity, variable pH, and co-occurring contaminants. This review evaluates non-graphene nanomaterials as emerging tools for mitigating radionuclide and heavy metal contamination, focusing on magnetic nanoparticles, metal oxides, nanoclays and zeolites, metal organic frameworks (MOFs), and biogenic nanoparticles. Graphene-based nanomaterials are excluded from the present review because they have been comprehensively addressed in a dedicated review previously published by the authors. A comparative evaluation of these nanomaterial classes demonstrates that no single material is universally optimal; rather, remediation performance depends on contaminant speciation, water chemistry, and operational requirements. Emphasis is placed on the mechanistic processes governing contaminant removal, including ion exchange, surface complexation, chemisorption, physisorption, and photocatalytic redox reactions. The role of environmental factors such as pH, ionic strength, competing ions, and natural organic matter in controlling nanomaterial performance is critically assessed. While laboratory studies demonstrate high removal efficiencies, practical implementation remains constrained by nanoparticle aggregation, long-term stability, recovery, and scalability under realistic mining-water conditions. The review highlights composite materials, immobilized nanostructures, green synthesis routes, and hybrid treatment systems as viable pathways for field deployment. This work underscores the importance of mechanistic insight and environmental compatibility in translating nanomaterial-based remediation strategies from laboratory research to sustainable water management solutions in mining-impacted environments.