Generic strategy to prepare PPy-based nanocomposites for efficient and stable interfacial solar desalination with excellent salt-rejecting performance

Abstract

The continual optimization and advancement of solar desalination technology represent an ongoing focal point in addressing the persistent challenge of freshwater scarcity. In the solar evaporator, subjected to high concentrations of saltwater and intense solar irradiation, as well as other demanding operational conditions, the presence of salt accumulation at the photothermal interface inevitably diminishes both the evaporation efficiency and the service life of the photothermal evaporator. In this study, we have successfully coated polypyrrole with carbon nanopowder (C), iron nanopowder (Fe), boron nitride (BN), boron carbide (B₄C), molybdenum disulphide (MoS₂), and molybdenum carbide (Mo₂C) through in-situ polymerization, and have assembled these coated materials with blends of polyvinyl alcohol/poly (vinylidene fluoride), creating an innovative amphiphilic photothermal composite film. The resulting thin-film evaporator has achieved an impressive 94.7 % evaporation efficiency under 1 sun irradiation. Introducing perforations on the film evaporator's surface further improves efficiency, reaching approximately 87.0 % under prolonged exposure to high salinity (20 %) conditions. This improvement is attributed to the increased water pathway facilitated by the perforations, preventing salt particle deposition on the evaporator's surface and significantly enhancing desalination efficiency.