Real-World Applications and Future Prospects of Nanomaterials in Water Treatment

Traditional treatment methods are jeopardized by aggravating water scarcity, as well as more intricate contaminant profiles (e.g., metals, nitrate, pathogens, and pharmaceuticals) along with emerging contaminants (PFAS, dyes, or microplastics). Nanomaterials are becoming increasingly important in membrane technology, which is centrally focused on the development of highly selective, energy-efficient purification processes rooted in tunable surfaces and high specific areas, as well as quantum-scale reactivity within certain nanomaterials. This chapter provides a comprehensive overview of the state-of-the-art in structure–property relationship knowledge across metals/metal oxides, carbon nanostructures, zeolites, and nanoclays, as well as metal–organic frameworks, and nanocomposite membranes, with correlations between these relationships and robust removal performance in realistic matrices. We dissect the broader mechanisms (adsorption, photocatalysis, antibacterial activity, redox conversion, and size-exclusion) into process design using fixed beds, reactive membranes, and catalytic contactors, including point-of-use devices. The intention is to provide a critical appraisal of field evidence from municipal, industrial, decentralized, and emergency contexts to inform techno-economic analysis, life-cycle assessment, and circularity considerations (material sourcing, regeneration, or end-of-life recovery). Compared to conventional technologies, these new treatment methods offer advantages related to increased selectivity, improved kinetics, modularity, and opportunities for low-energy operation, but challenges regarding particle release and ecotoxicity, risks associated with transformation products and by-products, membrane fouling, and performance decline in complex waters. The responsible development of nanotechnology requires engineered inclusions both to enable measurement methods and controls, but also to facilitate the integration of relevant information into models and regulatory frameworks that protect human health and the environment. This chapter will provide guidelines for safety-by-design (hazard banding, exposure control, and fate modeling), standardized performance testing with reference water matrices, and data sharing for comparability. There are also emerging directions in green synthesis pathways, bio-inspired and defect-engineered surfaces, stimuli-responsive and self-repairing materials, and coupled to sensors, digital twins, and AI-aided monitoring for closed-loop operation. Lastly, we provide innovation and implementation strategies to enhance equity and reliability within resource-limited settings, namely integration of nanomaterials with nature-based or biological trains to produce resilient hybrid systems. Taken together, the chapter highlights a mechanism-to-market perspective for deploying safe, scalable, globally relevant antimicrobial nanomaterial-based water treatment processes.