Enhancing freshwater production with a high-performance solar interface evaporator and in low-vacuum environment: A solar-driven low-vacuum interfacial distillation system

Solar-driven interfacial evaporation technology has immense potential in addressing the global challenge of freshwater scarcity. Currently, most solar interface evaporators have complex and costly manufacturing processes, hindering practical applications. Additionally, in many solar distillation systems, the evaporation and condensation processes occur within the same space. This causes sunlight to be scattered or absorbed by the water droplets on the transparent surface, thereby reducing the solar energy reaching the evaporator, the high internal humidity ratio further hinders water evaporation . Therefore, we developed a cost-effective polyvinyl alcohol/carbon black hydrogel (PCH) with a simple fabrication process. PCH achieves an evaporation rate of 1.54 kg m −2  h −1 and an energy conversion efficiency as high as 90.5 % under 1 sun (1 kW m −2 ). Furthermore, we have introduced a novel solar-driven low-vacuum interfacial distillation system (SLIDS) that separates the evaporation and condensation processes into distinct spaces and employs the principle of low pressure to enhance water evaporation. The condensate yield rate of the SLIDS was 1.46 kg m −2  h −1 , which is 2.2 times higher than traditional system under 1 sun. This increase in the condensate yield rate by 41.6 % was achieved through the introduction of low-pressure conditions.