Salt-rejecting rGO-coated melamine foams for high-efficiency solar desalination

Abstract Solar-driven interfacial desalination has been emerged as a promising water treatment technology to generate drinkable water out of seawater. The accumulated salt crystals generated from seawater, however, have adverse effects on solar-driven interfacial evaporation. In this work, we prepared a salt-rejecting reduced graphene oxide (rGO) foam by depositing rGO particles on a hydrophilic melamine foam for solar desalination. Benefitting from the intrinsic porous microstructure and hydrophilicity, the rGO-coated melamine foam has sufficient wettability to draw water to the evaporation region, leading to rapid replenishment of water and simultaneously avoiding salt precipitation. Based on the rGO-coated melamine foam, the interfacial evaporation system can achieve a steady-state evaporation efficiency of 89.6% under a solar flux of 1 kW m −2 and has good durability under one sun over 12 h. With the high solar-to-thermal conversion efficiency and excellent long-term stability, this interfacial evaporation system exhibits the potential of commercial seawater desalination. Graphic abstract