Integrated Solar Evaporator with Salt Resistance and Lipophobicity Derived from Waste Newspapers for Efficient Desalination

Abstract

Solar steam generation (SSG) is an effective way to mitigate the freshwater crisis. However, challenges still remain in scalable preparation, cost-effectiveness, and expanding the scope of practical applications for photothermal materials. Herein, a biomass-based solar steam generator (named OR-INP) with salt-resistant, oil-repellent, and anti-fouling performances is fabricated by grafting poly(ionic liquid)s onto celluloses from waste newspapers and then conducting oil-repellent modification. Benefiting from the broad solar absorption in the wet state (ca. 92%), low thermal conductivity (0.1108 W m–1 K–1), and strong hydrophilic and oleophobic properties, the solar evaporation efficiency is as high as 93.25% for pure water, 84.96% for 20 wt % NaCl, and 78.46% for 5 wt % oily wastewater, under 1 sun irradiation. Moreover, the aerogel still has excellent purification effects on solutions which contain organic dyes, heavy metal ions, or bacteria. Therefore, combining the merits of salt resistance, oil repellency, and wastewater treatment, this work develops the prospect of employing waste biomass resource-based photothermal materials and expands the practical application range of biomass-based evaporators.

Fabrication of Chitosan-Based Hydrogel Embedded with Antibacterial AgMXene Nanocomposites as Photothermal Centers for Solar Steam Generation and Purification

“…13,14 Apart from heat localization issues linked to solar evaporation, the microstructure and components of photothermal materials play a crucial role in determining the effectiveness of solar-driven steam generation. 15,16 Consequently, considerable focus has been devoted to the development of plasmonic nanoparticles, 17−21 conjugated polymers, 22 semiconductors, 23 carbon-based materials, 24,25 aerogels, 26,27 and hydrogels 28,29 for prospective solardriven water evaporation. Among these explored solar vaporproducing devices, photothermal hydrogels utilizing photothermal materials as "microheaters" to trigger solar-driven water evaporation have demonstrated significant potential in water conveyance and steam generation.…”

“…The progress in photothermal technologies has propelled the solar-driven interfacial steam evaporation technique into the spotlight as a promising technology for clean water production and wastewater treatment. It stands out for its improved heat utilization, high evaporation effectiveness, convenient installation, and flexible portability when compared to bulk heating-based methods. , Apart from heat localization issues linked to solar evaporation, the microstructure and components of photothermal materials play a crucial role in determining the effectiveness of solar-driven steam generation. , Consequently, considerable focus has been devoted to the development of plasmonic nanoparticles, − conjugated polymers, semiconductors, carbon-based materials, , aerogels, , and hydrogels , for prospective solar-driven water evaporation. Among these explored solar vapor-producing devices, photothermal hydrogels utilizing photothermal materials as “microheaters” to trigger solar-driven water evaporation have demonstrated significant potential in water conveyance and steam generation .…”

Reusable Floating Spherical Hydrogel Evaporator for Solar Desalination with Salt Mitigation and Contaminant Elimination

“…11−13 Initial research work in this direction focused on the development of efficient solar absorbers and the achievement of a high evaporation rate and energy conversion in order to provide a rational design for judicious heat management and water regulation. 14 Despite remarkable progress on each front, there are some issues that need to be addressed while designing an evaporation material. For instance, the synthesis of photothermal absorbers from sustainable materials or waste material must be emphasized, avoiding the expensive photothermal material and their delicate manufacturing process.…”

“…Initial research work in this direction focused on the development of efficient solar absorbers and the achievement of a high evaporation rate and energy conversion in order to provide a rational design for judicious heat management and water regulation . Despite remarkable progress on each front, there are some issues that need to be addressed while designing an evaporation material.…”

Hanging Photothermal Fabric Based on Polyaniline/Carbon Nanotubes for Efficient Solar Water Evaporation

“…This form of a single interfacial solar evaporation layer greatly increases the evaporation rate compared to bulk heating, but the entire bottom of the photothermal membrane is in direct contact with the bulk water and has a large heat dissipation area. − To reduce heat dissipation, photothermal layers are designed as multilayered or porous structures. − However, photothermal layers still have unavoidable heat loss to bulk water. To further improve the evaporation rate, the evaporation interface can be separated from the original bulk water surface to obtain better solar radiation concentration, such as jellyfish mode, hollow cone mode, arch mode, hanging mode, etc. − In one of them, Liu et al used a polyaniline-coated cotton fabric that was hung in an arc mode with the central portion lingering in the air, which exhibited efficient double-surface evaporation at a rate of 1.94 kg·m –2 ·h –1 under a solar illumination of 1.0 kW·m –2 .…”