Production of nano fiber using the electro spinning process to replace the conventional activated carbon filter at the directorate of government analytical lab

Abstract

Electro spun polyurethane fibers for removal of volatile organic compounds (VOC) from air with rapid VOC absorption and desorption have been developed. Polyurethanes based on 4,4-methylenebis (phenyl isocyanate) (MDI) and aliphatic isophorone diisocyanate as the hard segments and butanediol and tetramethylene glycol as the soft segments were electro spun from their solutions in N,N-dimethylformamide to form micron-sized fibers. Although activated carbon possessed a many-fold higher surface area than the polyurethane fiber meshes, the sorption capacity of the polyurethane fibers was found to be similar to that of activated carbon specifically designed for vapor adsorption. Furthermore, in contrast to VOC sorption on activated carbon, where complete regeneration of the adsorbent was not possible, the polyurethane fibers demonstrated a completely reversible absorption and desorption, with desorption obtained by a simple purging with nitrogen at room temperature. The fibers possessed a high affinity toward toluene and chloroform, but aliphatic hexane lacked the attractive interactions with the polyurethane chains and therefore was less strongly absorbed. The selectivity of the polyurethane fibers toward different vapors, along with the ease of regeneration, makes them attractive materials for VOC filtration.