Synthesis and adsorption properties of mesoporous MgAl₂O₄ spinel fibers by coaxial electrospinning

Abstract

Mesoporous magnesium aluminate (MgAl₂O₄) spinel fibers were prepared using a coaxial electrospinning technique. The phase composition, porous structure and adsorption performance of the mesoporous MgAl₂O₄ spinel fibers were investigated. Differential thermal/thermo-gravimetric and X-ray-diffraction analysis revealed that gel fibers began to crystallize into the MgAl₂O₄ spinel phase at 700°C and became fully crystallized at 900°C. The morphology changes in the fibers were tracked by use of a scanning electron microscope and transmission electron microscope, which showed fibers with a mesoporous structure formed at 900°C. The Brunner-Emmet-Teller specific surface area of MgAl₂O₄ spinel fibers is 36.95 m²/g. In addition, the dye adsorption capacity of the fibers shows an adsorption percentage of over 80.0% in 20 mg/l methylene blue after 2 min of adsorption. The kinetic study demonstrated that the adsorption data fit the pseudo-second-order kinetic model more naturally.