Enhancing water evaporation by interfacial silica nanoparticles

This study provides a simple nanoparticle–water system for enhancing the water evaporation in a low-cost and energy-efficient way. The particle–water system is achieved by depositing a layer of hydrophobic silica nanoparticles onto the water surface. The influence of the locally curved water surface, generated by interfacial nanoparticles, to the water evaporation rate is investigated. The experimental results show that the coverage of nanoparticle layer on the water surface enhances the water evaporation flux. A theoretical model based on Kelvin equation is proposed to explain the evaporation enhancement with the local curvature of water surface distorted by hydrophobic nanoparticles on water surface. The major influencing factors on the water evaporation enhancement are found to involve the coverage of nanoparticle layer, surface concentration of nanoparticles, and surface tension of water. The experimental findings offer a novel protocol for evaporation enhancement during water purification and salt mining.