Surface Characterization of Electrochemically Oxidized Activated Carbon Fibers and Their Capture Performance of Hazardous Air Pollutants

摘要

Activated carbon fibers (ACFs) have numerous advantages, such as light weight and excellentmechanical properties, so that they have been widely used in composite materials, adsorbentsand electrodes. In order to enhance their applications, usually it is necessary to require surfacetreatments of the ACFs. Several studies have reported that electrochemical oxidation couldincrease surface activity by generating more micropores and by introducing surface oxides.Therefore, the objective of this study was intended to understand the surface properties ofelectrochemically oxidized ACFs and further to evaluate their adsorption behaviors for isopropylalcohol (IPA) and methyl-ethyl ketone (MEK).One commercial polyacrylonitrile-based ACF was selected and electrochemically oxidized byapplying current to the fibers serving as an anode in 1 wt % aqueous KNO_3, where the extents ofelectrochemical oxidation were set at 1200 and 12000 C/g. Heat treatment of electrochemicallyoxidized ACFs was conducted in flowing nitrogen at 550 or 850 °C for 30 min to modify thesurface. The properties of the ACFs were probed using field emission scanning electronmicroscopy, elemental analysis, X-ray photoelectron spectroscopy and nitrogen adsorptionanalysis. Finally, the breakthrough curves of IPA and MEK vapors on the ACFs were measuredto evaluate the effect of electrochemical oxidation on ACFs adsorption performance.Results show that the electrochemical oxidation treatment significantly affected the surface