Cellular Structured CNTs@SiO₂ Nanofibrous Aerogels with Vertically Aligned Vessels for Salt‐Resistant Solar Desalination

Abstract

The emerging solar desalination technology is considered as one of the most promising strategies to ensure water security. However, with the proceeding of solar desalination, salt crystallization on the surface of solar evaporators caused by increasing salinity of seawater will result in a decrease in the evaporation rate. Thus, it is still challenging to fabricate solar evaporators with superior salt resistance. In this work, elastic ceramic‐based nanofibrous aerogels with a cellular architecture are fabricated by the combination of electrospinning and fiber freeze‐shaping technologies, which are composed of vertically aligned vessels and porous vessel walls. Under the action of convection and diffusion promoted by this unique cellular architecture, the aerogels exhibit a superior salt‐resistance without any salt crystals on the surface of aerogels even in 20% brine and under 6‐sun irradiation. Moreover, by virtue of the synergistic effect of the promising structure and light absorbance of carbon nanotubes, aerogels possess a high light absorbance of up to 98% and excellent evaporation performance achieving 1.50 kg m−2 h−1 under 1‐sun irradiation. This work may provide a fascinating avenue for the desalination of seawater in a salt‐resistance and efficient manner.

Salt Mitigation Strategies of Solar‐Driven Interfacial Desalination

“…For example, a CNTs@SiO 2 nanofiber aerogel (CNFAs) has excellent water transport and salt mitigation capabilities due to its vertically arranged and interconnected honeycomb structure. [ 99 ] The SiO 2 nanofibers obtained by electrospinning and subjected to freeze‐drying treatment to further obtain SiO 2 aerogels. The porosity of the aerogel formed by the close connection with CNTs through the dip‐coating is as high as 99.7%, which provides a large number of channels for the transportation of water and salt.…”

Biomimetic Ultra‐Black Sponge Derived from Loofah and Co‐MOF for Long‐Term Solar‐Powered Vapor Generation and Desalination

“…Solar‐powered vapor generation and desalination, which is an economical strategy that mainly utilizes solar energy and ultra‐black materials with efficient light absorption and photothermal conversion properties in solar band, is used to powerfully accelerate the evaporation of water and collect water and thereby solve the crises of drinking water shortage and water pollutions. [ 18–21 ] In the last few years, some evaporators based on different photothermal materials such as metal nanoparticles, [ 22–26 ] semiconductors, [ 27–30 ] polymers, [ 31–35 ] carbon materials, [ 36–48 ] and MXene [ 49–52 ] have been reported. However, most evaporators with high water evaporation rates and photothermal conversion efficiencies have some limitations in practical application scenarios, such as the use of expensive metals (Au and Ag) to enhance light absorption and photothermal conversion, strict and complex preparation processes to achieve microstructural control, and poor durability when used for solar‐powered desalination.…”

3D Printing a Biomimetic Bridge‐Arch Solar Evaporator for Eliminating Salt Accumulation with Desalination and Agricultural Applications

“…The most investigated evaporators based on porous structures are too fragile to sustain the high durability and reusability requirement as a solar evaporator. [12,17,34,36] Therefore, for further practical application, an all-in-one solar evaporator with high evaporation rate, superior salt-rejecting property, simple preparation process as well as excellent durable performance, is worth further investigation.…”