Development of a low-cost solar desalination device using porous silica for efficient freshwater production

Water scarcity limits access to fresh water despite 71% of the Earth's surface being covered by water, with 96.5% in seawater form. Conventional desalination methods, like reverse osmosis, are costly and energy-intensive. This project develops a low-cost desalination system using evaporation and condensation, incorporating hydrophilic porous silica synthesized from sodium silicate. The porous structure facilitates seawater transport, while insulation reduces energy loss, accelerating evaporation. To enhance efficiency, carbon black is integrated into the silica, improving solar absorption. Silica with 23.1% carbon achieved an evaporation rate of 2.08 L·hr⁻¹·m⁻², surpassing the natural evaporation of 1.21 L·hr⁻¹·m⁻², while preventing microbial and dust contamination.