A bilayer solar evaporator with all-in-one design for efficient seawater desalination.

Bilayer solar evaporator combines high photothermal conversion capacity and low heat loss, has become the new darling in interfacial solar steam generation (ISSG). However, the bilayer structure generally achieved by introducing a photothermal coating on the substrate is not conducive to long-term use due to the poor stability of coating. Herein, a fully biomass-based bilayer evaporator is all-in-one designed, using chitosan (CS) as building blocks and CS derived N, S - doped porous carbon (NSPC) as fillers via pre-freezing and freeze-drying. This facile method could realise the quantitative addition of photothermal materials and controllably regulate the structure of the bilayer evaporator, making the structural optimisation readily available. The optimised evaporator exhibits a remarkable evaporation rate of 2.51 kg m-2h-1. After 1000 times of pressing, it still maintains at 2.42 kg m-2h-1. Additionally, the evaporator displays outstanding long-lasting stability, excellent salt-resistant and degradability. More importantly, a solar desalination device is fabricated for harvesting freshwater outdoor. The daily water production per unit area (4.55 kg) meets the consumption of two adults. This work provides a controllable synthesis strategy of bilayer evaporators for handling global freshwater shortages.

Song C ，Jiang Z ，Gu X ，Li H ，Shi J ... -  《-》

Bio-Derived Photothermal Materials and Evaporators for Sustainable Solar Energy-Driven Water Process.

Ge Y ，Su Z ，Ivan MNAS ，Wang C ，Tsang YH ，Xu S ，Bai G ... -  《-》

Honeycomb-structured fabric with enhanced photothermal management and site-specific salt crystallization enables sustainable solar steam generation.

The emerging of solar-driven interfacial evaporation provides new opportunities to alleviate the shortage of fresh water resource. Nevertheless, in practical solar desalination, salt precipitation will lead to the decrease of evaporation rate due to reduced light absorption and blocked evaporation channels of evaporator. It still remains a challenge to eliminate salt accumulation and simultaneously maintain high-efficient evaporation. In this work, a solar evaporator was prepared based on reduced graphene oxide and chitosan coated honeycomb-structured fabric (rCHF). The rCHF showed a high light absorbance of 97.2% due to enhanced light trapping of the honeycomb structure and ultra-low thermal conductivity of 0.044 W m-1 K-1. Furthermore, the temperature gradient generated inside the honeycomb unit can induce the Marangoni effect, which led to the site-specific salt crystallization on rCHF in seawater evaporation. As a result, the rCHF realized an excellent solar evaporation rate of 2.02 kg m-2h-1 under one sun irradiation (1 kW m-2). The site-specific salt crystallization on the surface of rCHF ensured stable evaporation even in 20% brine, and the isolated salt can be removed by natural dissolution owing to the excellent hydrophilicity of rCHF. This work provides a new perspective for the design of solar evaporator for practical solar seawater desalination.

Gao C ，Zhu J ，Li J ，Zhou B ，Liu X ，Chen Y ，Zhang Z ，Guo J ... -  《-》

Scalable and low-cost fabrication of hydrophobic PVDF/WS(2) porous membrane for highly efficient solar steam generation.

Solar steam generation based on the light-to-heat conversion via photothermal materials has been considered as one of emerged technologies for utilizing solar energy to produce clean water. Here, a hydrophobic PVDF/WS2 porous membrane for highly efficient solar steam generation was prepared by a scalable and low-cost method. The WS2 photothermal materials were fabricated through a simple ball milling, and then a non-solvent induced phase inversion method was used to fabricate the porous PVDF/WS2 membrane. The PVDF/WS2 evaporator could absorb the sunlight of 90.58% from UV to NIR region due to the multiscattering of the porous structure and the synergistic effect of WS2 and seawater. Moreover, the PVDF/WS2 evaporator exhibits the hydrophobic properties. Taking the advantages mentioned above, our evaporator could manifest the evaporation rate of 4.15 kgm-2h-1 with the solar thermal efficiency of 94.2% under 3 sun irradiation, as well as an outstanding durability upon continuous running. Also, the evaporator shows both the excellent seawater desalination and sewage treatment ability. Outdoor experiments illustrate that the evaporator has practical applications under a natural sunlight condition. The numerous advantages of our PVDF/WS2 evaporator, including the high solar-thermal efficiency, the outstanding durability, and the simple and scalable manufacture process, may provide a potential photothermal material for the commercial solar desalination application and wastewater treatment.

Wei N ，Li Z ，Li Q ，Yang E ，Xu R ，Song X ，Sun J ，Dou C ，Tian J ，Cui H ... -  《-》

Janus Biopolymer Sponge with Porous Structure Based on Water Hyacinth Petiole for Efficient Solar Steam Generation.

Li J ，Chen S ，Li C ，Cao M ，Mu J ，Nawaz H ，Ling Z ，Xu F ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》