Eco-friendly desalination: improving evaporation rates in a solar still using agricultural waste materials

Access to clean drinking water remains a critical global challenge, particularly in remote areas with limited infrastructure. Solar stills offer a sustainable solution by utilizing solar energy to purify contaminated water through evaporation and condensation. This study investigates the performance enhancement of a triangular solar still by integrating thermoelectric heating and porous agricultural waste (corn husks) to improve evaporation rates. The design features a transparent glass triangular still with a 22° inclined cover, optimized for efficient vapor condensation. Two configurations were tested: a passive system relying solely on solar energy and an active system incorporating thermoelectric modules powered by a 100W solar panel. Results demonstrated that the active system significantly outperformed the passive one, producing 110 mL of distilled water over five hours compared to 68 mL, marking a 42 mL increase. The active system achieved a 3.7% evaporation efficiency, while the passive system reached 3.02%, confirming the thermoelectric module's contribution to heating and productivity. Additionally, corn husks enhanced water absorption and evaporation due to their porous structure. Water quality analysis confirmed a pH within the WHO-recommended range (6.5–8.5), ensuring safety for consumption. This study highlights the potential of thermoelectric-integrated solar stills combined with agricultural waste to improve freshwater production, offering an eco-friendly and cost-effective solution for water-scarce regions. Further optimization could enhance efficiency, making it a viable alternative to conventional desalination methods.