All-inorganic robust absorber for high-sun solar steam generation and solvent recovery

Abstract

The mechanical and chemical stability of the light-absorber creates a limitation of the STS applications, especially in harsh operating conditions such as high temperature or aggressive solvents environment. The current study addresses the issue by proposing a highly stable and durable light absorber based on the gold nanoparticles (Au NPs) immobilized on the mesoporous silica-covered glass fiber (MSGF). Mesoporous silica coating improves the attachment of Au NPs to the fiber surface, while simultaneously increasing specific surface area. The synthesis parameters of the mesoporous silica layer and the Au NPs were adjusted to obtain favorable morphology, resulting in a 16.7% increase in the total solar weighted absorptance. The STS system based on two-dimensional Au-MSGF achieved the highest evaporation rate of 1.22 kg·m −2 ·h -1 under 1 sun illumination at 20 °C and relative humidity of 40%. Furthermore, the thermal stability and durability of glass fiber allowed the application of Au-MSGF for the STS at sunlight illumination intensities as high as 50-suns without any visible or performance degradation over extended periods. The inertness of the Au-MSGF plays an important role in the solvent recovery applications of the STS system. It was found that the hydrophobic coating of the light absorber improves the performance of the STS system for non-polar solvent recovery. The results indicate a significant (over 100% as compared to the evaporation in the darkroom) evaporation rate increase of octane and decane in the STS system operating under 1 and 2 suns, making them suitable for the STS solvent recovery. • A highly stable all-inorganic absorber is developed for STS generation. • SiO 2 coating increases the surface area of glass fiber. • High sun STS generation is possible up to 50 Sun. • Solar induced solvent recovery using STS is successfully demonstrated. • STS-solvent recovery is efficient for solvents with low p v .