Combined effect of grooves and nanoflower structured Co₃O₄ coating on bamboo wood for highly efficient solar steam generation at indoor and outdoor conditions

Currently, interfacial solar steam generation (ISSG) in desalinating water has become very popular for obtaining purified water from polluted water. However, finding an efficient evaporator with low cost is a challenging task for researchers. In this work, we introduce natural bamboo wood (BW) that acts as an interfacial evaporator for obtaining purified water. Four different wood evaporators namely, flat wood (BW-FW), two-cut grooved wood (BW-2G), four-cut grooved wood (BW-4G), and four-cut grooved with Co₃O₄-coated wood (BW-4G/Co₃O₄) are used to study the mass loss (ML), evaporation rate (ER), and evaporation efficiency (EY). From the observations, BW-4G/Co₃O₄ gives an admirable ML, ER, and EY of 4.4 g, 3.366 kg m⁻² h⁻¹, and 91.34% under 1 sun illumination for 60 min. Also, the BW-4G/Co₃O₄ evaporator is kept under natural sun illumination. It achieves 17.8 g of ML, 1.92 kg m⁻² h⁻¹ of ER, and 76% of EY respectively under 604.762 W/m² solar illumination for 8 h. The reasons for the observed results are as follows: (i) the presence of grooves increases the exposing area for solar illuminations, (ii) super hydrophilicity nature of wood gives continuous replenishment of water from the bottom to the evaporative surface, (iii) the excellent salt rejection property of wood aids in continuous water transportation without salt accumulations. As a result of the condensed seawater samples, the ion concentrations (zinc, magnesium, cadmium, lead, copper, and sodium) come under WHO standards. Consequently, it gives better dye water separation from polluted water.