All-Day, All-Weather Desalination Using a Contactless Evaporator with Antisalt Fouling Property.

Abstract

Interfacial solar steam generation (ISSG) technology provides a promising solution to the global issue of freshwater scarcity. However, its practical application is hindered by salt fouling and inconsistent solar illumination. In this work, a novel interfacial solar steam generator is proposed that integrates contactless design with low-voltage joule heating to provide all-day, all-weather freshwater generation. The contactless design utilizes a solar-reduced graphene oxide coated carbon fabric (SRGO-CF) as a heat generator and super hydrophilic paper walls as water transport channels. The contactless device can generate steam at the maximum rate of 4.27 kg m^-2 h^-1 under 1 sun solar illumination and small input voltage due to the excellent photothermal and electrothermal capabilities of SRGO-CF. At an input voltage of 2.5 V, the SRGO-CF evaporator exhibits an evaporation rate of 3.52 kg m^-2 h^-1 and 2.32 kg m^-2 h^-1 for 3.5 wt % salt water respectively with and without 1 sun illumination for a long period of time without any salt fouling, demonstrating its all-day, all-weather capability. The proposed contactless ISSG evaporator can resolve the impractical issue of conventional ISSG-based evaporators owing to irregular weather conditions and salt fouling issues while also promoting zero liquid discharge-based salt harvesting.