Synthesis of hierarchical fabrics by electrospinning of PAN nanofibers on activated carbon microfibers for environmental remediation applications

Abstract

A novel hierarchal fabric was synthesized, consisting of poly-acrylonitrile (PAN) nanofibers electrospun on a mat of activated carbon microfibers (ACF), used as a substrate. Electrospun PAN nanofibers were stabilized by preoxidizing in air at 250 °C. The multiscale web (ACF-PANS) of stabilized nanofibers on ACF thus prepared was further pyrolyzed and activated by steam at 900 °C to prepare a hierarchical activated carbon fabric (ACF-PANC). These multiscale fabrics (ACF-PANS and ACF-PANC) were tested for its adsorption properties toward common atmospheric air pollutants, such as SO₂, NO, and toluene, a volatile organic compound (VOC) and the performance was compared to ACF and another hierarchical carbon fabric fabricated by growing carbon nanofibers on metal-impregnated ACF (ACF-CNF) by chemical vapor deposition. Interestingly, the performance of the electrospun PAN nanofibers based multiscale carbon-polymer fabric after stabilization (ACF-PANS) was found to be superior to that of ACF, ACF-PANC and ACF-CNF fabrics. A variety of surface characterization techniques demonstrated that the PAN nanofiber-based stabilized hierarchical fabrics contained relatively large amounts of nitrogen-based surface functional groups that favored the adsorption and catalytic oxidation of SO₂ and NO. On the other hand, the pore volume and specific surface area of the materials were found to affect the adsorption of toluene. This study reveals the considerable potential of the stabilized electrospun PAN nanofiber-based hierarchical fabric (ACF-PANS) materials as adsorbents for air pollution control.