SiO₂/MXene/Poly(tetrafluoroethylene)-Based Janus Membranes as Solar Absorbers for Solar Steam Generation

Abstract

Water treatment through interface photothermal conversion using solar energy is a sustainable strategy for freshwater supply. Because the preparation method of highly efficient photothermal conversion materials with commercial value is the only way for the industrialization of solar steam generation, the preparation method and the rational design of photothermal materials are particularly important. In this work, the highefficiency photothermal conversion material MXene nanosheets and low thermal conductivity SiO 2 were coated on a hydrophilic poly(tetrafluoroethylene) (HPTFE) membrane by a commercial continuous spraying system to produce a SiO 2 /MXene/HPTFE Janus membrane. They possess excellent mechanical properties, high stability, and 93.0% light absorption. The prepared evaporator can be used for water treatment with a photothermal evaporation rate of 1.53 kg m −2 h −1 , achieving a uniform and effective 85.6% solar thermal conversion efficiency, which is superior to most reported work. The removal rate of wastewater and organic pollutants can reach 99.9%. At the same time, the two-dimensional Janus membrane has excellent salt resistance and self-cleaning ability, making it easy to store and transport. It is also used to build sensor systems. The sensor has an excellent light response and can accurately measure solar radiation density and temperature in a short time. Therefore, the use of commercial spraying systems provides a cost-effective and energy-saving strategy for photothermal evaporators and sensors to reduce the use of photothermal materials, achieve higher photothermal evaporation rates, and expand the application direction of photothermal materials.

Highly Effective Multifunctional Solar Evaporator with Scaffolding Structured Carbonized Wood and Biohydrogel

“…The difference among the performance of the three evaporators indicates the effect of scaffolding structure and MXene on the evaporation efficiency. CMSK shows an excellent evaporation rate and the largest energy efficiency, being superior to most reported ones (Figure g). ,− Based on eqs – for the calculation of evaporation efficiency in Section , the high evaporation efficiency of the evaporator is attributed to the high temperature generated on the evaporator surface and the high evaporation rate.…”

Janus Carbon Nanotube@poly(butylene adipate-co-terephthalate) Fabric for Stable and Efficient Solar-Driven Interfacial Evaporation

“…It was found that the four kinds of ion concentrations were significantly reduced and the ion concentrations of Na + , Mg 2+ , K + , and Ca 2+ were well below the World Health Organization (WHO) standard for drinking water, indicating that the freshwater condensed by the Janus CNT@PBAT fabric was clean and safe enough for human consumption. The above results indicated that the as-prepared 3D water channel evaporator shows outstanding and stable evaporation rates and salt resistance performance, which are comparable to or even higher than those of the previously reported superhydrophobic Janus solar evaporator, as summarized in Figure f and Table S1. ,,− ,− Moreover, the as-prepared 3D WCE equipped with the Janus fabric had a potentially low cost due to both the renewable and cost-effective cotton fiber and the facile process (shown in Table S2).…”

Solar-driven interfacial evaporation for water treatment: advanced research progress and challenges

“…The Cu@CuO/CG-aero Janus membranes prepared by Zhao et al 246 exhibited an efficient purification performance for wastewater by solar energy, and the results of using the modified membranes to treat wastewater continuously for 6 days showed almost uniform evaporation per day and no fouling, indicating their long-lasting durability. Li et al 247 prepared a SiO 2 /MXene/poly(tetrafluoroethylene) Janus membrane with a removal rate of 99.9% for heavy metal ions and dye contaminants. The temperature change trend was basically the same for various cycles in the cyclic heating-cooling test, which indicated that it has excellent physical and mechanical properties, making it stable and reusable.…”