Surface-Modified Activated Carbon Fibers by a Facile Microwave Technique for Enhancing Hydrocarbon Adsorption

Evaporative emissions from automobiles, which mainly consist of hydrocarbons, are a major source of air pollutants. As such, prevention means are required to minimize such emissions. Evaporative emissions are collected using adsorbents, where the adsorption capacity is directly influenced by the ratio of oxygen-containing functional groups, which have high polarity. This study investigated the effect of controlling the oxygen functional group (OFG) on the hydrocarbon adsorption/desorption performance of activated carbon fiber (ACF) in adsorbents. We used microwave heating to remove OFG on the ACF surfaces. The removal of surface OFG by microwave heating was analyzed using scanning electron microscopy-energy-dispersive X-ray spectroscope (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric-infrared gas analysis (TGA-IR), and X-ray photoelectron spectroscopy (XPS). According to microwave heating, textural properties were analyzed using N-2/77K adsorption/desorption isotherms. The hydrocarbon adsorption/desorption performance of the ACF was evaluated according to a modified ASTM D5228. Compared to the untreated ACF, the butane working capacity of the modified (non-polarized) ACF was increased by up to 20% (adsorption capacity 27%).