Enhanced evaporation performance of solar interface evaporator by modifying the evaporation layer surface with hydrophobic fumed silica

Abstract

Modifying the interface of the interfacial evaporator has been shown to be an effective way to increase the evaporation rate. In this study, a new method of modifying hydrophobic fumed silica (FS) on the evaporation layer surface is proposed to enhance the evaporation performance of the interfacial evaporator. It is found that the FS suspension concentration has great control over the microstructure and surface wettability of the evaporated layer, and the water-air interface area of the evaporated surface is effectively expanded. As a result, the evaporation rate within the closed chamber is enhanced by ∼14% to 1.33 kg m−2 h−1 at the light intensity input of 1 kW m−2. The mechanism of performance enhancement is illustrated by simulations and modeling calculations. To further improve the evaporation performance, we constructed a 10-stage multistage distillation (MSD) device to recycle latent heat and achieve an evaporation rate of 5.03 kg m−2 h−1 at 1 kW m−2 light intensity. In addition, the device was proven to operate efficiently and stably in brine and achieve zero liquid discharge. Therefore, the method of modifying an appropriate amount of FS has a good prospect for solar desalination.