Highly salt-resistant organic-inorganic composite as a solar-driven interfacial evaporator for desalination and electricity generation

Abstract

The desalination of seawater through solar-driven interfacial evaporation becomes an increasingly important and efficient route to solve the shortage of fresh water. However, this route faces a poor durability during the evaporation because of salt accumulation on the surface of photothermal material and its corrosion. Here, we put forward a novel strategy of constructing the organic-inorganic composite (FeS2-Mo2S3/GF@PDA@STA) as a photothermal material for desalination of seawater and heavy metal ion wastewater to generate clean water. In our work, FeS2-Mo2S3 and polydopamine (PDA) were integrated to achieve photothermal conversion, and then were covered by stearic acid (STA) to attain hydrophobic effect. Next, the hydrophobic photothermal material was further combined with hydrophilic air-laid paper to form a solar-driven evaporation system, which contained photothermal conversion and water supply. Under irradiation of 1 sun, this evaporation system achieved a high evaporation rate of 1.34 kg m−2 h−1 as well as photothermal conversion efficiency of 89 %. This evaporation system also offered an excellent durability at different light intensities, and superstrong salt-resistant ability. Besides, synergistic electricity generation was observed, and achieved a maximum output power of 0.18 W m−2 under 1 sun during the solar-driven interfacial evaporation. In addition, this evaporation displayed an excellent performance for purifying several heavy metal ion solutions such as Cr3+, Ni2+, Cu2+ and Pb2+, in which the ionic contents of the purified water were far lower than drinking water stated by WHO (World Health Organization) standard. This work opened up a novel avenue for desalination of seawater and purification of heavy metal ion wastewater to generate clean water through the organic-inorganic composite by virtue of solar-driven interfacial evaporation.