Enhancing interfacial solar steam generation using hybrid (Co3O4/perovskite structured NaTaO3) nanomaterials coated on cotton cloth with sawdust composite evaporator

Abstract

Interfacial solar steam generation (ISSG) is an emerging technology, used for the replenishment of water scarcity on the globe. In ISSG process, an interfacial evaporator is allowed to float on the bulk water surface to produce steam. Here, the different interfacial evaporators such as cotton cloth (CC), epoxy+hardener+sawdust (EHS) composite covered with cotton cloth (E-CC), EHS composite covered with Co3O4 coated cotton cloth (E-CC/Co3O4) and EHS composite covered with hybrid nanomaterial (Co3O4/ NaTaO3) coated cotton cloth (E-CC/hy1 and E-CC/hy2) are developed and experimented under 1 sun illumination. The synthesized NaTaO3 and Co3O4 photothermal materials are characterized using UV, XRD, FT-IR, FE-SEM, TEM and TGA respectively. Among all the evaporators, E-CC/hy2 attains an outstanding mass loss of water, evaporation rate and evaporation efficiency of 5.7 g, 4.92 kg m−2 h−1 and 117.78% respectively. In addition, the ion concentration of the condensed water is measured and found to be below WHO standards. Also, the dye degradation level of four different dyes is experimentally studied and found to be excellent dye degradation level for all the tested samples. The obtained results are mainly due to (i) the coating of Co3O4/ NaTaO3 composite over the top surface of the evaporator that traps the solar light efficiently (ii) the improved surface roughness that reduces the scattering and reflection of solar light (iii) the presence of excellent hydroxyl water absorbing groups in cotton cloth and better refilling of water at the evaporative surface of the evaporator (iv) low thermal conductivity of cotton cloth and EHS evaporator that inhibits the heat travel to the bulk water and glass beaker though conduction and convection.