Biologically inspired silk fibroin grafted polyacrylonitrile filtration membrane prepared in ZnCl2 aqueous solution

Abstract

In this study, biologically inspired silk fibroin grafted polyacrylonitrile (SF-g-PAN) filtration membrane was prepared using ZnCl2 aqueous solution as solvent, avoiding the use of organic solvents. Phase inversion occurred when Zn2+ and Cl− ions gradually diffused into water, creating a well-connected ion channel network and the SF-g-PAN filtration membrane was obtained. The membranes were observed by SEM and 3D ultra-depth microscope. The hydrophilic property, pore size distribution and dye rejection of the membrane were investigated. Results showed that the membrane has no finger hole formation because ZnCl2 aqueous solution has a lower curing rate parameter compared with organic solvents. SF-g-PAN membrane possessed good anti-fouling properties and pH sensitivity. The pore size distribution of the SF-g-PAN membrane was 0.25–1.04 nm. The rejection of direct yellow 27 (Mw = 662.6) and amaranth (Mw = 604.5) was 96.51% and 30.63%, with the flux of 72.32 L m−2 h−1 and 73.83 L m−2 h−1 respectively at 0.1 MPa. The SF-g-PAN membrane has a wide range of applications prospect in fine separation, dye desalination, waste water treatment and biomedical fields.