Fast benzene vapor capture by natural macroporous carbonized fibers improved with carbon nanostructures

Abstract

We investigated the adsorption of benzene, as a model volatile organic compound from gasoline, in a novel macroporous carbon material, with the intention of improving the kinetics performance of porous materials in automotive canisters. In this research, we proposed agave bagasse fibers, that when pyrolyzed develop wide pores all along the fiber, that are helpful in vapor diffusion. To enhance the surface area of the carbonized fibers, we grew diverse carbon nanostructures onto fibers surface by chemical vapor deposition. The as-produced materials were characterized by N2 physisorption, FTIR, SEM, TEM, XRD and Raman spectroscopy. The carbon nanostructures formed, such as bamboo-like carbon nanotubes, onion-like carbon and carbon black, increased the surface area of carbonized fibers from 120 to 185 m2 g−1, while their thermal post-treatment at 800 °C doubled the surface area, up to 243 m2 g−1, of the pristine carbonized fibers. The adsorption of benzene vapor showed that carbonized fibers containing carbon nanostructures have 1.8 faster adsorption kinetics (0.0064 mmol min−1) and 1.5 higher adsorption capacity (55.53 mg g−1) after 26 h of static adsorption than a commercial granular activated carbon, which is used nowadays in automotive canisters. The pseudo-second order model provided the best fit to the kinetic rates.