Nanofluid‐assisted solar still desalination: Recent advances, thermal performance enhancement and future research directions: A comprehensive review

Freshwater scarcity is a major global challenge driven by population growth, industrialization, climate change, and declining freshwater resources. This review systematically and critically evaluates recent advances in nanofluid‐assisted solar still desalination, focusing on freshwater productivity, thermal performance, energy and exergy efficiency, stability, economic feasibility, and environmental sustainability. A systematic literature search was conducted following the PRISMA 2020 framework using Scopus, Web of Science, ScienceDirect, IEEE Xplore, and Google Scholar for peer‐reviewed studies published between 2022 and 2025. Of 343 records initially identified, 82 studies satisfied the predefined eligibility criteria and were included in the qualitative synthesis. Unlike previous reviews focusing primarily on individual enhancement techniques, this review integrates metallic, metal oxide, carbon‐based, and hybrid nanofluids with phase change materials, advanced absorber modifications, AI/ML/CFD applications, techno‐economic considerations, and commercialization prospects within a unified framework. The reviewed evidence indicates that nanofluids enhance solar absorption, heat transfer, evaporation, and freshwater productivity, although performance strongly depends on nanoparticle type and concentration, dispersion stability, water depth, solar irradiance, climatic conditions, and still configuration. Al 2 O 3 and CuO exhibit strong thermal‐performance enhancement, whereas carbon‐based and hybrid nanofluids show promising photothermal characteristics. However, long‐term stability, environmental impacts, durability, cost, and commercialization remain major challenges. This review identifies current research gaps and provides future directions toward efficient, sustainable, and commercially viable solar desalination systems.