Self-floating porous PVDF/CNT microspheres for solar desalination

Abstract

Abstract The application of photothermal materials for achieving continuous and efficient solar interfacial evaporation possesses substantial research significance in solar desalination. To realize continuous and efficient evaporation, interfacial evaporation materials must integrate high light absorption capacity, superior photothermal conversion performance, sufficient water supply, and buoyancy. In this study, polyvinylidene fluoride/carbon nanotubes (PVDF/CNT) self-floating porous microspheres, suitable for solar interfacial water evaporation, were synthesized via a convenient phase transformation method. The microspheres’ distinct composition and porous structure enable effective sunlight absorption, sufficient water flow, and quick steam discharge. Additionally, the performance of the microspheres is enhanced as the content of CNTs increases. These microspheres can absorb up to 93.8% of incident sunlight and elevate the water surface temperature to 41.5 °C within 2 minutes. Under one-sun illumination, the water evaporation rate (WER) reaches 1.485 kg/m2·h, with a solar energy conversion efficiency (SECE) of 93.1%.