Amidoxime functionalized Polymers of Intrinsic Microporosity (PIM-1) electrospun ultrafine fibers for rapid removal of uranyl ions from water
Date
2018Source Title
Applied Surface Science
Print ISSN
0169-4332
Publisher
Elsevier
Volume
467-468
Pages
648 - 657
Language
English
Type
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Abstract
The Polymers of Intrinsic Microporosity (PIM-1) is considered as one of the most promising polymer candidates
for adsorption applications owing to its high surface area and the ability to tailor the functionality for the
targeted species. This study reports a facile method for the preparation of amidoxime functionalized PIM-1
fibrous membrane (AF-PIM-FM) by electrospinning technique and its practical use for the extraction of U(VI)
ions from aqueous systems via column sorption under continuous flow. Fibrous membrane form of amidoxime
functionalized PIM-1 (AF-PIM-FM) was prepared by electrospinning method owing to its excellent processability
in dimethylformamide. Bead-free and uniform fibers were obtained as confirmed by SEM imaging and average
fiber diameter was 1.69 ± 0.34 μm for AF-PIM-FM. In addition, electrospun PIM-1 fibrous membrane (PIM-FM)
was prepared as a control group. Structural and thermal characterization of powder and membrane forms of the
materials were performed using FT-IR, 1
H NMR, XPS, Elemental analyses, TGA, and DSC. The porosity of the
samples was measured by N2 sorption isotherms confirming amidoxime PIM-1 still maintain their porosity after
functionalization. Amidoxime functionality along with membrane structure makes AF-PIM-FM a promising
material for uranyl adsorption. First, a comparison between powder and membrane form of amidoxime functionalized PIM-1 was investigated using batch adsorption process. Although membrane form has shown slightly
lower adsorption performance in the batch adsorption process, the advantage of using the membrane in column
adsorption processes makes membrane form more feasible for real applications. In addition, amidoxime modification enhanced the uranium adsorption ability of PIM-FM up to 20 times. The effect of initial concentration
and pH were investigated along with regeneration of the adsorbents. AF-PIM-FM was successfully used for five
adsorption-desorption cycles without having any damage on the fibrous structure.