PVDF based Janus composite membrane for collaborative solar-driven interface evaporation and photocatalysis with high salt-resistance and anti-biofouling

The development of solar-driven interface evaporation (SDIE) technology is considered as one of the highly promising approaches for purifying seawater and wastewater treatment. However, simultaneously achieving superb evaporation rates, excellent salt resistance and protection against biofouling, and being able to operate in various water resources is still remains a significant challenge. In this work, a composite PVDF Janus membrane with schottky junction (PC-SP-MCN) was fabricated by using polyvinylidene fluoride (PVDF) as the basement membrane, the poly(ionic liquid)s grafted SiO 2 (SiO 2 -PILs) as the hydrophilic agent, calcium carbonate (CaCO 3 ) and hydrochloric acid (HCl) as pore-forming agents, and MXene/g-C 3 N 4 was employed as the photocatalyst. Under the solar irradiance of 1 kW m −2 , the PC-SP-MCN can achieve an evaporation rate of 1.51 kg m −2  h −1 , resulting in an impressive evaporation efficiency of 91 %. When tested in the NaCl solution with a concentration of 20 wt%, the evaporation rate and efficiency of PC-SP-MCN was calculated to be 1.39 kg m −2  h −1 and 83 %, respectively. Furthermore, the PC-SP-MCN also exhibited satisfied abilities in photocatalytic degradation and antibacterial properties. It can degrade methyl orange (MO), rhodamine B (RhB), and methylene blue (MB) in simulated dye wastewater effectively, while also display significant inhibitory effects on Escherichia coli and Staphylococcus aureus . The PC-SP-MCN that has been prepared exhibits ample porosity, efficient pathways for water molecule transport, outstanding ability to absorb sunlight, and minimal conductivity of heat. And it also exhibited an efficient SDIE performance, superb photodegradation, and antimicrobial properties. This study gives a new perspective to integrate different properties into the SDIE system and expand its application, especially in desalination and wastewater treatment.