Sulfur vacancy-rich molybdenum disulfide 3D evaporator enhanced photothermal conversion for seawater desalination and wastewater purification

Solar-driven interfacial evaporation for seawater and other wastewater is widely viewed as green, environmental technology to generate clean water. Herein, the sulfur vacancy-rich MoS 2 -sodium alginate-filter cotton aerogel evaporator was designed to purify seawater, heavy metal wastewater and dyestuff wastewater for production of clean water. From analysis of XPS spectra, 2H-MoS 2 dominates in B MoS 2 (bulk MoS 2 ) while 1 T-MoS 2 becomes a major phase in SS MoS 2 (ultrathin and sulfur vacancy-rich MoS 2 ). EPR measurement reveals that SS MoS 2 possesses far richer sulfur vacancies than B MoS 2 . SS MoS 2 displays a stronger broadband absorption ability and lower reflectance than B MoS 2 . As a result, SS MoS 2 -based evaporator offered more excellent water evaporation performance than B MoS 2 -based evaporator. Under irradiation of 1 sun, the SS MoS 2 -based evaporator achieves a high evaporation rate of 2.03 kg m −2 h −1 which is higher than the B MoS 2 -based evaporator with 1.58 kg m −2 h −1 , demonstrating that sulfur vacancy has an enhanced effect for photothermal conversion. The SS MoS 2 -based evaporator also displays an excellent evaporation rate of seawater, close to pure water. Besides, this evaporator shows an excellent durability for seawater desalination, and maintains a self-cleaning effect. In addition, this evaporator offers an excellent performance for purifying heavy metal wastewater, in which the heavy metal ionic concentration of the purified water is far lower than drinking water stated by the standard of World Health Organization. Encouragingly, this evaporator can also purify dyestuff wastewater to generate clean water by evaporation, adsorption and photocatalysis. This work presents a novel strategy for desalination of seawater and purification of heavy metal wastewater and dyestuff wastewater to generate clean water by integrating the defected MoS 2 into sodium alginate aerogel evaporator.