Trapezoidal solar evaporators with salt resistant and extraction working modes

Abstract

Interfacial solar evaporators utilize sunlight to produce sustainable freshwater but salt accumulation on evaporator surfaces hinders its efficiency. In this study, we present a novel bilayer symmetric evaporator for interfacial solar evaporation, composed of trapezoidal structures designed for efficient salt resistance, and salt extraction. The evaporator is made of carbonized coconut fiber cloth and incorporates the innovative Symmetrical Trapezoidal Salt Resistance (STS-R) and Symmetrical Trapezoidal Salt Resistance Extraction (STS-E) models. This innovative design achieved an evaporation rate of 2.26 kg m^–2 h^–1 under one sun, with a conversion efficiency of 80.16 %. The evaporator showed excellent salt resistance and salt extraction performance in 14 ∼ 16 wt% NaCl solutions, as well as sea salt solution while maintaining a high evaporation rate. STS enables directional ion migration, enhances capillary action and wicking, maximizes surface area and light absorption, promotes heat localization, and facilitates a self-cleaning mechanism. This unique approach effectively tackles salt accumulation issues in water purification and desalination processes.