Enhanced solar desalination by delignified wood coated with bimetallic Fe/Pd nanoparticles

In this paper, a new cost-effective method has been developed to utilize solar energy for steam generation. For the first time, the delignified wood was chosen as a self-regenerating substrate coated with Fe/Pd bimetallic nanoparticles (NPs) as either single or double-layer solar photoabsorbers. The results revealed that in the case of single-layer, the optimum wood thickness, the thickness at which maximum evaporation rate and minimum heat loss occur, is 10 and 5 mm for the deionized water and seawater, respectively. Under the radiation of 3 sun (3 kW m(-2)), the evaporation efficiency was enhanced up to 103% using the wood with a thickness of 5 mm coated with Fe/Pd NPs compared to the case in which evaporation happens from the seawater surface without any absorber on the surface (conventional case). In order to increase the evaporation rate, a double-layer substrate was utilized. The lower layer was composed of either wood or polystyrene foam with a thickness of 5 mm while the upper layer was composed of wood with 5 mm thickness coated with Fe/Pd NPs. The results showed 126% and 167% enhancement in evaporation efficiency for Fe/Pd W5W5 (wood with a thickness of 5 mm coated with nanoparticles in the upper layer, and wood with a thickness of 5 mm in the lower layer) and Fe/Pd W5F5 (wood with a thickness of 5 mm coated with nanoparticles in the upper layer, and foam with a thickness of 5 mm in the lower layer), respectively, compared to that of the seawater. Moreover, the economic analysis indicated that using two-layer photoabsorber (Fe/Pd W5F5) is an affordable technique for solar steam generation compared to some previously reported methods in the literature.