Solar-powered graphene desalination unit for national water security

Climate variability, aging infrastructure, and the energy intensity of conventional desalination are constraining reliable freshwater supply. This manuscript proposes the Solar‑Powered Graphene Desalination Unit (SPGDU), a conceptual, distributed desalination architecture that integrates (i) solar‑photothermal preheating/evaporation with engineered salt management, (ii) a nanoporous graphene‑oxide membrane stage for selective transport and pretreatment, and (iii) direct‑drive photovoltaic electrodialysis (PV‑ED) operated with a flow‑commanded current controller to reduce or eliminate battery dependence. The design targets resilient community‑scale production from brackish and seawater (order‑of‑magnitude 2–5 m³ day⁻¹ per modular unit) while incorporating basic sensor monitoring and cyber‑resilience considerations. We synthesize literature‑reported performance envelopes, provide an integration schematic with flow pathways and control interfaces, and outline a quantitative scaling envelope for salt crystallization avoidance and/or harvesting. SPGDU is presented as a framework to guide prototyping, validation, and techno‑economic assessment for water‑security applications.