Search

Solar desalination is a promising strategy to utilize solar energy to purify saline water. However, the accumulation of salt on the solar evaporator surface severely reduces light absorption and evaporation performance. Herein, a simple and eco‐friendly method to fabricate a 3D gradient graphene spiral sponge (GGS sponge) is presented that enables high‐rate solar evaporation and zero liquid discharge (ZLD) desalination of high‐salinity brine. The spiral structure of the GGS sponge enhances energy recovery, while the gradient network structures facilitate radial brine transport and directional salt crystallization, which cooperate to endow the sponge with superior solar evaporation (6.5 kg m−2 h−1 for 20 wt.% brine), efficient salt collection (1.5 kg m−2 h−1 for 20 wt.% brine), ZLD desalination, and long‐term durability (continuous 144 h in 20 wt.% brine). Moreover, the GGS sponge shows an ultrahigh freshwater production rate of 3.1 kg m−2 h−1 during the outdoor desalination tests. A continuous desalination–irrigation system based on the GGS sponge for crop growth, which has the potential for self‐sustainable agriculture in remote areas is demonstrated. This work introduces a novel evaporator design and also provides insight into the structural principles for designing next‐generation solar desalination devices that are salt‐tolerant and highly efficient. [ABSTRACT FROM AUTHOR]

Abstract Solar desalination is a promising strategy to utilize solar energy to purify saline water. However, the accumulation of salt on the solar evaporator surface severely reduces light absorption and evaporation performance. Herein, a simple and eco‐friendly method to fabricate a 3D gradient graphene spiral sponge (GGS sponge) is presented that enables high‐rate solar evaporation and zero liquid discharge (ZLD) desalination of high‐salinity brine. The spiral structure of the GGS sponge enhances energy recovery, while the gradient network structures facilitate radial brine transport and directional salt crystallization, which cooperate to endow the sponge with superior solar evaporation (6.5 kg m−2 h−1 for 20 wt.% brine), efficient salt collection (1.5 kg m−2 h−1 for 20 wt.% brine), ZLD desalination, and long‐term durability (continuous 144 h in 20 wt.% brine). Moreover, the GGS sponge shows an ultrahigh freshwater production rate of 3.1 kg m−2 h−1 during the outdoor desalination tests. A continuous desalination–irrigation system based on the GGS sponge for crop growth, which has the potential for self‐sustainable agriculture in remote areas is demonstrated. This work introduces a novel evaporator design and also provides insight into the structural principles for designing next‐generation solar desalination devices that are salt‐tolerant and highly efficient.

Abstract Owing to the lightweight, flexibility, and molecular diversity, organic photothermal materials are considered promising solar absorbent materials for water‐evaporating purification. Herein, we utilize the blend of two organic conjugated photothermal materials, PM6 and Y6, with broadband solar absorption from 350 to 1000 nm and high‐efficiency photothermal properties to fabricate a Janus water evaporator on cellulose paper. Similar to the asymmetric wetting behavior on the lotus leaf, the evaporator shows efficient water adhesion on the bottom surface and water repellency on the top surface for a desirable self‐floating capability and salt resistance. With a mass of only 0.5 mg per 3.14 cm2, the PM6:Y6 blend‐based water evaporator achieves 88.9% of solar thermal conversion efficiency (η) and 1.52 kg m−2 h−1 of solar water evaporation rate (m) under 1.0 kW m−2 solar irradiation. These properties are almost the best performance among purely organic water evaporators especially with such a premise of material saving. The concentrations of primary ions are significantly decreased by 4–6 orders after desalination, accompanied by excellent performance for wastewater treatment. This evaporator realizes a m of 1.21 kg m−2 h−1, a η of 75.7%, and a voltage of 61 mV under one sun irradiation by assembling with a thermoelectric equipment. This study demonstrates that the blending of PM6 and Y6 achieves photothermal synergism, which improves the photothermal property and water evaporation rate, providing a valuable prospect for their application in water purification and thermoelectric power generation.

The 3D steam generator with cold evaporation surface (CES) provides a means for high‐efficiency interfacial steam generation due to the low heat loss and continuous ambient energy input. However, the poor floating stability of CES steam generators when suffering wave slamming has limited their practical application in open water. Herein, a cellulose‐based monolithic aerogel integrated with three structural elements is developed inspired by tumblers, which can synchronously achieve outstanding antioverturning stability in waves and a high evaporation rate (4.21 kg m−2 h−1). A single‐stage solar water purification device is constructed based on the photothermal aerogel, which attains an ultra‐high daily water yield of ≈32.6 L m−2 and surpasses a large amount of single‐stage solar stills. The steam generator can also be used to purify wastewater containing Co2+ via adsorption. Gratifyingly, the Co3O4/C catalyst obtained from the pyrolysis of aerogels loaded with Co2+ exhibits good catalytic activity for carbon monoxide oxidation, demonstrating the potential for waste conversion. This work provides new insights into the design of solar steam generators used in open water, and offers a promising way for the disposal and utilization of contaminated steam generators after wastewater purification. [ABSTRACT FROM AUTHOR]

Solar‐powered interfacial evaporation has emerged as an innovative and sustainable technology for clean water production and it has motivated the design and fabrication of monolithic 3D steam generators and related hybrid applications. However, the existing porous and hydrophilic 3D scaffolds fabricated via conventional processing techniques remain one of the main roadblocks toward scalable and mass applications. Herein, a series of closed‐cell 3D polymer foams is developed via a "rotating" gas‐foaming technique. Monopile supporting structures with reticulated and hydrophilic gas pockets are formed in the 3D foams, resulting in controlled shapes and heights, ultralight weight, efficient water diffusion, and optimized solar and environmental energy input. Gratifyingly, the 3D foam with a selected height of 12 cm attains an outstanding water evaporation rate of 5.8 kg m−2 h−1 under 1 sun. Furthermore, selected photothermal, adsorbent, and photocatalytic materials on the 3D foam introduce water remediation beyond clean water production, exhibiting organic pollutant removal efficiencies over 90% in indoor and outdoor experiments. An ease‐of‐mold approach to shape‐controlled fabrication of polymer foams is demonstrated and their intriguing properties for solar‐powered hybrid applications such as organic pollutant removal in wastewater are highlighted. [ABSTRACT FROM AUTHOR]

Abstract Solar interfacial evaporation holds great potential for desalination. Currently, abundant and renewable biomass appears to be the most sustainable evaporator candidate for addressing environmental and energy challenges. However, the widespread use of biomass‐based evaporators is hampered by the formation and deposition of salt on the evaporation surface. Herein, we present a hierarchical photothermal aerogel inspired by the leaves‐on‐stems architecture in pristine plants. It is formed with microchannels severing as stems and nanospikes as leaves. Microchannels with large pores enable quick brine replenishment, while numerous nanospikes increase the available surface area for vapor generation. In contrast to the macro‐scale salt‐resistant design, which ruins the overall structure of the evaporator, we modified the microchannel structure within the biomass, allowing the biomass evaporator to effectively resist salt while maintaining efficient evaporation performance. The unique hierarchical micro‐nano structure of this photothermal aerogel allows it to achieve a high evaporation rate of 1.78 kg m−2 h−1 under 1 sun and a continuous evaporation time of 100 h without salt deposition in a high‐salinity brine (15 wt%), outperforming most previously reported evaporators derived from biomass. Additionally, the anti‐biofouling capacity of the evaporator is effectively demonstrated for long‐term operation through the development of an enhanced freshwater collection prototype, highlighting the potential for sustainable off‐grid solar desalination.

Solar‐driven interfacial evaporation has emerged as an innovative and sustainable technology for efficient, clean water production. Real‐world applications depend on new classes of low‐cost, lightweight, and robust materials that can be integrated into one monolithic device, which withstands a variety of realistic conditions on open water. Self‐repairing building blocks are highly desired to prevent permanent failures, recover original functions and maintain the lifetime of interfacial steam generators, although related studies are scarce to date. For the first time, a monolithic, durable, and self‐floating interfacial steam generator with well‐defined structures is demonstrated by integrating self‐healing hydrogels through facile processes in surface modulation and device fabrication. High and stable water evaporation rates over 2.0 kg m−2 h−1 are attained under 1 sun on both fresh water and brine with a broad range of salinity (36–210 g kg−1). The solar evaporation and desalination performance are among the best‐performing interfacial steam generators and surpass a majority of devices that are constructed by composite polymers as structural components. This study provides a perspective and highlights the future opportunities in self‐healing and damage‐tolerant materials that can simultaneously improve the performance, durability, and lifetime of interfacial steam generators in real‐world applications. [ABSTRACT FROM AUTHOR]

Solar‐driven interfacial evaporation is an emerging technology with a strong potential for applications in water distillation and desalination. However, the high‐cost, complex fabrication, leaching, and disposal of synthetic materials remain the major roadblocks toward large‐scale applications. Herein, the benefits offered by renewable bacterial cellulose (BC) are considered and an all‐cellulose‐based interfacial steam generator is developed. In this monolithic design, three BC‐based aerogels are fabricated and integrated to endow the 3D steam generator with well‐defined hybrid structures and several self‐contained properties of lightweight, efficient evaporation, and good durability. Under 1 sun, the interfacial steam generator delivers high water evaporation rates of 1.82 and 4.32 kg m−2 h−1 under calm and light air conditions, respectively. These results are among the best‐performing interfacial steam generators, and surpass a majority of devices constructed from cellulose and other biopolymers. Importantly, the first example of integrating solar‐driven interfacial evaporation with water wave detection is also demonstrated by introducing a self‐powered triboelectric nanogenerator (TENG). This work highlights the potential of developing biopolymer‐based, eco‐friendly, and durable steam generators, not merely scaling up sustainable clean water production, but also discovering new functions for detecting wave parameters of surface water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of closed-cell hydrogel foams via a controlled foaming − gelation technique. • Demonstration of self-contained solar evaporation and desalination. • Realization of a single-stage water purifier for efficient clean water production. Solar-powered interfacial evaporation has emerged as a sustainable technology for clean water production with a minimized carbon footprint. Fabrication of three-dimensional (3D) steam generators via conventional processing techniques (sol–gel and template-assisted methods) remain one of the main roadblocks toward mass production and scalable applications. In this study, 3D hydrogel foams based on biopolymer composites are developed via a controlled foaming − gelation technique and applied to a monolithic interfacial steam generator. The designed closed-cell structures deliver many important form-factors to the hydrogel foams, such as light-weight, low-cost, low thermal insulation and efficient water diffusion. The hydrogel foam with a maximum height of 3.2 cm attains a high water evaporation rate of 2.12 kg m−2h−1 and a high cost-effectiveness of 2692 g h−1 $−1 under one sun. A single-stage water purification system is fabricated based on the high-performing hydrogel foam. Because of its self-floating structure and enhanced passive cooling on open water, the system attains a maximum clean water collection rate of 0.71 L m−2h−1 under real sky and surpasses a majority of single-stage solar stills. This work demonstrates the rational fabrication of hydrogel foams and combines high-performance solar evaporation with other intriguing properties (i.e., cost-efficient, scalable, anti-biofouling, self-floating and anti-overturning). The system-level design enables facile scale-up of clean water production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Construction of an interfacial steam generator by using nanocellulose extracted from marine biomass. • Rational fabrication of nanocellulose-based aerogels as structural elements. • Realization of a 3D monolithic interfacial steam generator for efficient and durable solar evaporation. Solar-driven interfacial evaporation is an emerging and sustainable technology with growing potential for applications in water distillation and desalination. Despite the ongoing progress in clean water production, the high cost, delicate structures, leaching and disposal of synthetic materials remain the major roadblocks toward large-scale and real-world applications. Herein, nanocellulose (NC) is successfully extracted from abundant, inexhaustible and biodegradable biomass Ulva (Enteromorpha) prolifera that collected from the coast of Qingdao, China. Incorporation of polyvinyl alcohol (PVA) into the NC scaffolds and subsequent cross-linking endow the composite aerogels with efficient water diffusion, enhanced mechanical strength and good deformation resistance. The cross-linked composite aerogels can serve as main structural elements and integrate a monolithic, self-floating and durable steam generator. Under one sun, the good water evaporation rate of 1.4 kg m−2 h−1 is among the best-performing interfacial steam generators constructed by using cellulose-based materials as structural components. This study demonstrates a new concept of using marine (blue) biomass-derived NC as crude material and building block to construct high-performance and durable interfacial steam generators, synergistically considering clean water production and sustainability of marine ecosystems. [ABSTRACT FROM AUTHOR]