Preparation of flexible electrospun AOPAN/PVDF membranes for removing Pb2+ from water

Abstract

Abstract Electrospun AOPAN/PVDF composite nanofiber membranes for metal ions treatment have been prepared by coaxial electrospinning. AOPAN shell layer was modified chemically for adsorbing metal ions by chelation, whereas the chemically stable PVDF inner core was for maintaining mechanical stability. Polymer concentration and applied voltage had obvious influence on the characteristics of the fibers’ structure, morphology and strength. The amidoxime reaction was sensitive to the pH value of solution, and it was found that the alkaline condition hindered the reaction. The characterization by SEM, FTIR and XRD showed that the AOPAN/PVDF membrane retained the core–shell structure integrity after chemical modification. In the static and dynamic adsorption experiments, the mechanical strength of the AOPAN/PVDF membrane did not change obviously within 5 cycles of adsorption and regeneration. In addition, the AOPAN/PVDF membranes showed a certain level of efficiency in removal of Pb2+ in aqueous solution; the adsorption capacities of the membranes in the 5th run were higher than 45% of the adsorption of the corresponding fresh membranes. The work provides a potential approach for preparing membranes having good feasibility for practical application in adsorption separation of metal ions. Graphical Abstract

Keywords

• Coaxial electrospinning
• Membrane durability
• Amidoxime
• Pb2+ removal