Directional solution transfer of a 3D solar evaporator inhibiting salt crystallization

Abstract

Solar interface evaporation with high thermal utilization and evaporation rate has great application potential for seawater desalination. Improving evaporation performance and inhibiting the formation of crystalline salt are the key to achieve long-term continuous and efficient solar desalination. In this study, a novel 3D hydrogel evaporator constructed from cotton, reduced graphene (rGO), sodium alginate (SA) and polyvinyl alcohol (PVA) was prepared by a simple method. The evaporator showed an excellent evaporation rate of 4.57 kg m⁻² h⁻¹ and kept high-performance evaporation without salt crystallization for 5 days. Based on the excellent water transport capacity and the exceptional 3D structure, the evaporator realized cold and heat dual-mode evaporation enhancing the evaporation performance and the suppression of salt crystallization by directional solution transfer. This work aimed to solve the shortage of freshwater resources by developing sustainable and high-performance solar desalination technology.