Photocatalytic removal of nitrate using TiO2/polyacrylonitrile nanofiber membrane synthesized by co-electrospinning process
The present study investigates the development of titanium dioxide (TiO2)/polyacrylonitrile (PAN) nanofiber membrane for the removal of nitrate from aqueous solution by photocatalysis. The TiO2 nanoparticles were synthesized by conventional sol–gel method followed by blending them into PAN polymer. The blended solution was electrospun into nanofiber using the co-electrospinning technique. The nanoparticle, PAN nanofibers and the TiO2 impregnated nanofibers were characterized using suitable techniques like X-ray diffraction, high-resolution transmission electron microscopy and scanning electron microscopy attached with energy dispersive X-ray spectroscopy. The average size and the diameter of the TiO2 nanoparticles and TiO2/PAN nanofibers were found to be 22 ± 0.32 nm and 90 ± 15 nm respectively. TiO2 nanoparticles and TiO2/PAN nanofibers showed maximum nitrate removal of 74.67 and 39% respectively at 10 mg/L nitrate concentration at pH 4. However at higher concentration (50 mg/L), the nitrate removal was found to be only 16.87%. The experimental data were fitted onto pseudo second-order kinetic model. The impregnation of TiO2 nanoparticles into the PAN nanofibers by co-electrospinning techniques lead to higher removal of nitrate in aqueous solution at lower concentration (10 mg/L and below). However at higher concentration, the TiO2/PAN nanofiber membrane was inefficient to remove nitrate.