Experimental and theoretical investigation of industrial solar desalination ponds enhanced with nano-ferric oxide for sustainable freshwater production

The escalating global demand for freshwater necessitates the development of efficient and sustainable desalination technologies. This study presents an experimental and theoretical evaluation of a solar desalination pond enhanced with nano-ferric oxide (Fe2O3) plates and compares its performance with a conventional steel-based system. Incorporation of Fe2O3 significantly improved solar absorption and thermal conduction, resulting in a maximum brine temperature of 74 °C compared with 68 °C for the conventional configuration. The modified system achieved a maximum daily freshwater productivity of 6.5 L m−2 day−1, corresponding to an average improvement of 27–30% based on daily mean productivity over comparable operating days, while instantaneous hourly productivity gains reached up to 60% under peak summer solar irradiance conditions. Maximum thermal and exergy efficiencies increased from 0.41 to 0.53 and from 5.9% to 7.8%, respectively. The developed heat and mass transfer model exhibited strong agreement with experimental results (R2 ≈ 0.985, deviation < ± 3.1%). These findings demonstrate that nano-ferric oxide is a low-cost, environmentally benign, and scalable enhancement material capable of significantly improving the performance of solar desalination systems, offering a viable pathway for sustainable freshwater production in arid and resource-limited regions.