Sustainable Wood-Based Hierarchical Solar Steam Generator: A Biomimetic Design with Reduced Vaporization Enthalpy of Water

Abstract

Water purification by solar distillation is considered a promising technology for producing clean water from undrinkable water resources. A solar steam generator is a central part of a solar distillation process to separate water and contaminants. Here, we report an efficient and sustainable hierarchical solar steam generator (HSSG) with reduced vaporization enthalpy based on bacterial cellulose (BC) nanocomposites. The nanomaterials are assembled with BC nanofibers produced by bacteria in situ to form nanocomposites. Using this method, we construct functional BC nanocomposites inside and on the natural porous structure of wood. Our HSSG integrates solar-to-vapor efficiency improvement and vaporization enthalpy reduction by integrating the hierarchical multifunctional BC nanocomposites with the natural porous structure of wood. Because of the biomimetic design, hierarchical structure and reduced vaporization enthalpy of HSSG, a high evaporation rate of 2.9 kg m–2 h–1 and solar-to-vapor efficiency of 80% is achieved.

An all-natural bioinspired structural material for plastic replacement

“…As one of the most abundant all-green resources on Earth, CNF, a high-performance one-dimensional (1D) nanoscale building block, can be derived from plants or produced by bacteria (Supplementary Fig. 1 ) 23 , 24 . It possesses high strength (at least 2 GPa), a low coefficient of thermal expansion (CTE) (1 × 10 −7 K −1 ), and abundant hydroxyl and carboxyl groups on the surface, indicating it to be an ideal biopolymer matrix for brick-and-mortar structure 24 – 27 .…”

Biomimetic Antigravity Water Transport and Remote Harvesting Powered by Sunlight

“…Synthetic Trunk Fabrication: The synthetic procedure of the artificial trunk is reported previously with slight modification. [10] Briefly, 0.5, 1.0, 1.5 or 2.0 g of chitosan (degree of deacetylation = 90%; from Shanghai Macklin Biochemical Co., Ltd) was dispersed in 96 mL of deionized water (DIW; 18.2 MΩ; Milipore). Simultaneously, 2 mL of glacial acetic acid was added dropwise into the dispersion with continuous manual stirring to form an optically clear solution.…”

“…[9] After freeze-drying, the chitosan microchannels were in situ acetylated into β-chitin by acetic anhydride in a methanol solution to build up mechanically and chemically more stable channels for water transport ( Figure S2, Supporting Information). [10] Under our reaction condition, a full Figure 1. Design and characterization of the artificial trunk-leaf system in trees.…”

Passive, high-efficiency thermally-localized solar desalination

“…4j) since the latent heat of water is almost a constant ( ≈ 2400 kJ/kg). However, several recent studies show that it is possible to produce more than 2.5 L m -2 h -1 of water using hydrogel 31,32,59 and bacterial cellulose nanocomposites, 87 which indicates a reduction of water latent heat during evaporation (the bluedashed circle in Fig. 4j).…”

“…4j). 26, [28][29][30][31][32]46,48,51,53,55,58,59,70,80,[84][85][86][87] The reported studies used thermal localization to achieve solar-vapor conversion efficiencies greater than 50%. By incorporating thermal management strategies discussed above, the demonstrated can be as high as 90% with more than 1.5 L m -2 h -1 water production rate under the one sun illumination.…”