Case study on solar thermal-assisted desalination: Enhancing efficiency and water purity using a nano CuO-coated floating absorber

Solar desalination effectively mitigates water scarcity by utilizing direct sunlight. Saltwater desalination was carried out using a coated solar still (CSS) and a traditional solar still (TSS) at depths of 3, 5, and 7 cm, respectively. The coated solar still was made more efficient by adding (30 wt%) of copper oxide (CuO) on the sides of the solar basin, increasing heat convection. The coated CuO nanoparticle, measuring 0.05 mm in thickness, was secured to the water surface using a floated frame during the water level adjustment. This study was carried out over three days, examining various water depths while maintaining consistent climatic conditions. The TSS and CSS yields were 250 ml, 260 ml, and 255 ml, based on measurements taken at 3 cm, 5 cm, and 7 cm water depths, respectively, for the cumulative distillate water production. At a water level of 5 cm, the cumulative water production of the CSS increased by 71% to 445 ml compared to the measurements taken on the previous two days. While in TSS, the pH of the salty water dropped to 7.86, in CSS, it fell to 7.46. Water with a high salt content has its total dissolved solids (TDS) cut in half.