Membrane-based desalination Technologies for Water Treatment: A critical review and future outlook

This review critically evaluates membrane-based desalination technologies for saline water treatment through a systems-level comparative framework integrating membrane materials, transport mechanisms, process efficiency, and sustainability across diverse salinity regimes, with particular emphasis on nanofiltration as a strategic energy-efficient selective desalination platform. Unlike conventional descriptive reviews, this review introduces context-aware benchmarking to demonstrate that desalination performance metrics, including specific energy consumption, water recovery, selectivity, and operational complexity, are fundamentally condition-dependent and cannot be universally compared in isolation. Reverse osmosis (RO) remains the dominant large-scale desalination platform due to its high salt rejection and economic scalability, while nanofiltration (NF) is repositioned as a strategic intermediate-pressure technology enabling selective ion separation, process intensification, and hybrid system optimization. Emerging advances in nanocomposite, graphene oxide (GO)-based, cellulose acetate-derived, and biomimetic membranes are critically assessed with respect to permeability–selectivity trade-offs, fouling resistance, manufacturability, and long-term operational feasibility. The analysis further highlights the growing importance of hybrid desalination architectures, renewable-energy integration, and circular resource recovery for improving environmental sustainability. Key research gaps are identified in membrane stability, scale-up translation, techno-economic validation, and standardized performance assessment. This review establishes a unified analytical roadmap for sustainable membrane desalination, demonstrating that desalination performance is inherently context-dependent and highlighting NF as a strategic transitional platform linking RO and thermally driven systems for future research, industrial application, and water security advancement.