Confinement Capillarity of Thin Coating for Boosting Solar‐Driven Water Evaporation

Abstract

Realizing ultrathin water and generating an abundant water/air interface in the interconnected pores of photothermal materials is an effective way to boost the solar-driven water evaporation rate, but still a great challenge. Herein, confinement capillarity (CC) of photothermal thin coating on porous sponge for significantly enhancing the solar-driven water evaporation is proposed. The thin coating is composed of abundant agminated black/hydrophilic nanoparticles (BHNPs), and the channels among the BHNPs can generate strong capillarity for water transportation. Water can be spontaneously limited and transported among the agminated nanoparticles, rather than fill in the interconnected pores of the sponge. Thus, ultrathin water layer can be realized on the outer/inner surface of the sponge skeleton, without precisely controlling water supply. The thin water layer can not only expose as much evaporation area as possible by increasing the vapor escape channel, but also prevent solar energy to heat excess water. Thanks to the CC, the rate of solar steam generation can be greatly improved. Moreover, the photothermal material with CC can maintain its high evaporation rate during the whole day, and can remove the salt during night time, highlighting its recyclability and anti-salt-accumulation property. Moreover, the CC can be readily scaled up for practical applications.

Complete System to Generate Clean Water from a Contaminated Water Body by a Handmade Flower-like Light Absorber

“…The majority of the research in this field has focused on how to get a better evaporation rate. 35 Focusing only on the evaporation rate is not much fruitful. Obtaining clean water for drinking purposes is a critical objective in this research area.…”

High-performance salt-resistant solar interfacial evaporation by flexible robust porous carbon/pulp fiber membrane

“…2.5 L). Notably, the concentration of Na + in gathered water after desalination (3.3 ppm) is sharply decreased by three orders of magnitude compared with the seawater (22,197.9 ppm), and below the standard defined by the World Health Organization (WHO) [28,[60][61][62][63]. The concentrations of other main ions (e.g., K + , Mg 2+ and Ca 2+ ) in the gathered water go down significantly (Fig.…”

Bilayer rGO‐Based Photothermal Evaporator for Efficient Solar‐Driven Water Purification[]**

“…Notably, these microchannels also transferred water molecules from the bottom to the top surface of aerogel by capillary action, thereby forming micro-zone water columns to promote water evaporation. [32,33] From the magnified SEM image of the bottom layer (Figure 1e), abundant wrinkled rGO-SA composites were observed, which may play a crucial role in increasing surface-specific area as well as providing more adsorption sites for contaminants. [34] The magnified SEM image of the upper layer (Figure 1c) depicted the uniform distribution of TiO 2 particles on the surface of wrinkled rGO-SA composites.…”