Thermodynamic reconfiguration of high-recovery seawater desalination: integrating staged reverse osmosis, osmotic gradient engineering, and brine resource recovery

While seawater reverse osmosis has a theoretical minimum energy requirement of 1.06 kWh/m³, practical operations still consume between 3 and 4 kWh/m³. This efficiency gap becomes most critical when recovery rates exceed 50%, as the resulting spike in osmotic pressure forces a non-linear increase in operational costs and hydraulic demand. To overcome these thermodynamic hurdles, we propose a reconfiguration strategy based on smart retrofitting. By applying a multi-staged approach—specifically integrating next-generation technologies like low-salt rejection reverse osmosis and osmotically assisted reverse osmosis—the system can redistribute entropy and osmotic loads more effectively. Furthermore, integrating brine mining strategies such as membrane distillation or ion exchange allows for the recovery of valuable resources, effectively offsetting exergy losses. Ultimately, this integration transforms desalination from a simple water production utility into a synergistic water-energy-resource nexus, paving the way for AI-driven optimization and sustainable zero liquid discharge platforms.