Electrospun polyacrylonitrile-based lace nanostructures and their Cu(Ⅱ) adsorption

• Functionalized porous polyacrylonitrile nanofiber membranes were prepared through the combination of coaxial electrospinning and simple post-processing. • The nano-MgO inlaid on the surface of the porous functional fibers presents a lace mesh structure. • The functionalized porous nanofiber membrane shows high adsorption capacity and good recycling performance. • The functionalized porous nanofiber membrane provides an opportunity to treat actual copper-containing wastewater. High performance nanostructures for efficient heavy metal treatment are highly desired in our daily life. A functionalized porous nanofibrous membrane loaded with MgO nanoparticles prepared by coaxial electrospinning and post-processing method was studied to remove copper ions from aqueous solutions. The solid core layer is used to support the functional layer of the sheath with lace-like porous structure, and to obtain the composite nanofiber membrane with super adsorption performance. The functional fiber membrane has a larger specific surface area, a more uniform diameter distribution and surface pores than other nanofibers, moreover, showing the dual advantages of good mechanical properties and hydrophilicity. Adsorption of copper ions reached equilibrium within 3 h with an optimal adsorption pH of 5 and a maximum adsorption capacity of 354 mg/g. The pseudo-second-order kinetic model and the Langmuir model can well describe the single-layer chemisorption process between copper ion and functional membrane. After the functional fiber membrane was repeatedly used for 5 times, the adsorption removal efficiency remained at 70%, which indicates that the recycling performance was good. The functionalized nanofiber membrane has a simple preparation and high removal efficiency, and is an effective material that can address heavy metal-polluted water.