Electrospun Ag/Al2O3 fibers for removal of methylene blue

Abstract

In this work, electrospun Ag/Al2O3 fibers were prepared by the sol–gel electrospinning methods in order to apply as sorbent and catalyst in photocatalytic reaction for removal of methylene blue. The electrospun Ag/Al2O3 fibers at various silver concentrations (2, 5 and 10%w/w) and different calcination temperatures (350 and 500 oC) were prepared. The electrospun Ag/Al2O3 fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-VIS spectroscopy, X-ray Diffraction Analysis (XRD) and nitrogen adsorption/desorption analysis. The phase of alumina in Ag/Al2O3 fibers was gamma-alumina phase and the average diameter of obtained fibers was 75 nm. The average diameters of silver particles in Ag/Al2O3 fibers ranged from 3 to 13 nm and were in the form of Ag0 and Ag2O. Then the electrospun Ag/Al2O3 fibers were applied for the removal of methylene blue in water. The removal efficiency of methylene blue by adsorption process was mainly from the host alumina which showed the percent removal of 54.8%. However, the calcined 10%w/w Ag/Al2O3 fibers at 350oC enhanced the removal efficiency of methylene blue by photocatalytic degradation approximately 2 times (% removal of methylene blue was 25% for Al2O3 and 48% for calcined 10%w/w Ag/Al2O3 fibers at 350oC). As a result, the Ag/Al2O3 fibers (calcined 10%w/w Ag/Al2O3 fibers at 350oC) exhibited the great effectiveness in the removal of methylene blue in water with 95.3% removal (47.3% by adsorption process and 48.0% by photocatalytic degradation). In addition, the electrospun Ag/Al2O3 fibers were easily collected and can be reused up to 3 times without the loss of photocatalytic degradation performance.