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 becomes very popular for obtaining purified water from polluted water. But, finding a suitable evaporator with low cost and high-efficient is the challenging task for researchers. In this work, we introduce natural bamboo wood 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 is 4.4 g, 3.366 kg/m²h and 91.34 % under 1 sun illumination for 60 min. Also, it is kept at open atmosphere conditions under natural sun illuminations. It achieves 17.8g 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. We suggest the following are the reasons for the observed results: (i) the presence of grooves increase the exposing area for solar illuminations (ii) the 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 is employed for continuous water transportation without salt accumulations. As a result, the salinity of the condensed water is measured that comes under WHO standards. Consequently, it gives better dye removal from polluted water.