Fabrication of porous hollow γ-Al2O3 nanofibers by facile electrospinning and its application for water remediation

In this paper, we fabricated porous hollow γ-Al2O3 nanofibers by the facile single-capillary electrospinning of an aluminum nitrate (Al(NO3)3)/polyacrylonitrile (PAN) precursor solution, followed by sintering treatment. The nanofibers were characterized by scanning electron microscopy, thermogravimetric analysis, X-ray diffraction. N2 adsorption–desorption isotherm analysis showed that the specific surface area and average pore size of the nanofibers were 67.17 m2 g−1 and 17.3 nm, respectively. A possible mechanism based on the Kirkendall effect was proposed to explain the formation process of the hollow structure. The pore size and diameter of the nanofibers can be tailored by changing the weight ratio of Al(NO3)3·9H2O to the PAN. Moreover, the prepared porous hollow γ-Al2O3 nanofibers were used as adsorbents to eliminate three model dyes (i.e., Congo red, methyl blue, and acid fuchsine) from aqueous solutions. The material exhibited excellent dye adsorption efficiency at a removal ratio greater than 90% in 50 mg L−1 dye solutions after 60 min of adsorption. Kinetic studies were performed and pseudo-first order, pseudo-second order were carried out. The nanofibers also exhibited desired adsorption cycle performance and the ability to regenerate easily. By virtue of the facile electrospinning method, it provides possibilities to fabricate other porous hollow nanofibers with potential applications in the environmental remediation, catalysis, and biomedical fields.