Surface modification of electrospun polyacrylonitrile nanofiber towards developing an affinity membrane for bromelain adsorption

Non-woven polymer membrane prepared by electrospinning technique is a potential material for affinity membrane application. In this work, electrospun polyacrylonitrile (PAN) nanofiber membranes were surface modified and studied as a novel affinity membrane, using bromelain as a research model. Firstly, chitosan (CS) was tethered onto the electrospun membrane surface to form a dual-layer biomimetic membrane through the use of glutaraldehyde (GA). The dye Cibacron Blue F3GA (CB) as a ligand was then covalently immobilized on the CS-coated membranes. The changes of chemical structures were characterized by element analysis, SEM, ATR-FT-IR and DSC. The content of CB attached onto the membrane was 370 μmol/g membrane, and the CB-attached PAN nanofibers membrane showed a capturing capacity of 161.6 mg/g towards bromelain. The adsorption isotherm fitted the Freundlich model well. This work demonstrated that the electrospun PAN nanofiber membrane has potential for affinity membrane applications in wastewater treatment system.