Electrospinning preparation, characterization, and enhanced photocatalytic activity of an Silicotungstic acid (H4SiW12O40)/poly(vinyl alcohol)/poly(methyl methacrylate) composite nanofiber membrane.

Tingting Li, Zhiming Zhang, Wei Li, Ce Liu, Haoyu Zhou and Libao An

Journal of Applied Polymer Science

DOI: 10.1002/app.43193

Graphical abstract

Abstract       

Silicotungstic acid (H4SiW12O40)/poly(vinyl alcohol) (PVA)/poly(methyl methacrylate) (PMMA) composite nanofiber membranes were prepared by an electrospinning technique. A PMMA emulsion was mixed with PVA and H4SiW12O40 evenly in water (electrospinning solvent). The configuration and elemental composition of the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results indicate that H4SiW12O40 with an intact Keggin structure existed in the composite membrane. The as-prepared H4SiW12O40/PVA/PMMA membranes exhibited enhanced photocatalytic efficiency (>84%) in the degradation of methyl orange (MO); it outperformed H4SiW12O40 powder (4.6%) and the H4SiW12O40/PVA nanofiber membrane (75.2%) under UV irradiation. More importantly, the H4SiW12O40/PVA/PMMA membranes could be easily separated from the aqueous MO solution, and the photocatalytic efficiency of the membranes decreased inappreciably after three photocatalytic cycles. This may have been due to the enhanced water tolerance of the membranes and the stability of H4SiW12O40 in the membranes. The photocatalytic process was driven by the reductive pathway with a much faster degradation rate because of the presence of PVA.