Interfacial solar evaporation based on Janus films: An effective strategy to improve salt tolerance and antifouling performance

The emerging interfacial solar evaporation technology is an effective measure to address freshwater resources, but the complex diversity of sewage is rarely considered. Janus films with asymmetric wettability instead of conventional homogeneous films for interfacial solar energy evaporation are a creative development. The water-air is relocated inside the evaporator, and the pollutants return to the water body. This review presents recent advances and challenges in solar-driven interfacial evaporation based on Janus films. Firstly, the advantages of Janus film-interface solar evaporators are summarized, and they have superior purification ability compared with traditional structures. Secondly, according to the survey, four common basic structures are summarized: flat sheets, hollow fibers, electrospun nanofibers, and tree-like structures. Thirdly, the materials required to construct Janus films for interfacial evaporation are summarized, mainly carbon-based materials, metal nanomaterials, polymer materials, and semiconductor materials. The fourth part discusses the multi-media purification function of the Janus membrane according to the classification of seawater desalination, organic pollution purification, heavy metal ion purification, acid-base wastewater purification, and bio-fouling purification. Then we summarize the three main challenges currently facing: ensuring water flux, reducing evaporation enthalpy of water molecules, and improving long-term stability and economical production.