Magnetic field assisted synthesis of JANUS Fe3C@ Enteromorpha doped graphene aerogels for simultaneous recovery of fresh water and salt in high salinity wastewater

•With the assist of magnetic field, Fe3 C@ Enteromorpha doped graphene aerogel (GEF) is synthesized by a one-step hydrothermal reduction method.•Enteromorpha interact with GO to form a unique structure with abundant micropores in the longitudinal direction and layered structure in the lateral direction.•The magnetic NZVI is adsorbed to the surface of the aerogel with the assist of magnetic field.•GEF has excellent photothermal evaporation performance and salt resistance.