Surface chemistry, pore sizes and adsorption properties of activated carbon fibers and precursors treated with ammonia Original Research Article

A series of activated carbon fibers (ACFs) were produced by treatment with ammonia to yield a basic surface. The micropore sizes of these chemically modified fibers were determined with nitrogen adsorption experiments and they were shown to increase with increasing activation time and temperature. The types of groups present were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and temperature programmed desorption (TPD). The adsorption isotherms of an acidic gas (HCl) show a great improvement in capacity over an untreated acidic fiber. The adsorption is completely reversible and must therefore involve enhanced physical adsorption instead of chemisorption. This demonstrates that ACFs can be tailored to selectively remove a specific contaminant based on the chemical modification of their pore surfaces.