Coal fly ash based porous ceramic evaporator for highly efficient solar-driven seawater desalination

Solar-interfacial evaporation has shown great potential for desalination using green energy. However, salt accumulation and long-term stability of the evaporators are urgent problems. Here, we designed a ceramic interfacial evaporator using black glaze and coal fly ash (CFA) with durability and technological maturity characteristics. A porous CFA ceramic substrate was prepared by the dry pressing method, and the black glaze was coated on the surface as a photothermal material. The thermal conductivity and porosity of the CFA ceramic are 0.564 W·m −1 K −1 and 40 %, respectively. The average evaporation rate was 1.443 kg·m −2  h −1 under one sun. Outdoor solar desalination experiments were conducted. The highest evaporation rate was 2.949 kg·m −2  h −1 under natural sunlight. The ceramic evaporator showed good salt resistance during two days of continuous desalination experiments. This work highlights the feasibility of using CFA-based ceramic evaporators for efficient solar-driven seawater desalination.