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

A series of activated carbon fibers (ACFs) were produced by treatment with ammonia to yield a basic surface. The micropore sizes of these chemically m odified fibers were determined with nitrogen adsorption experiments and the y were shown to increase with increasing activation time and temperature. T he types of groups present were analyzed by Fourier transform infrared spec troscopy (FTIR). X-ray photoelectron spectroscopy (XPS), and temperature pr ogrammed desorption (TPD). The adsorption isotherms of an acidic gas (HCl) show a great improvement in capacity over an untreated acidic fiber. The ad sorption is completely reversible and must therefore involve enhanced physi cal adsorption instead of chemisorption. This demonstrates that ACFs can be tailored to selectively remove a specific contaminant based on the chemica l modification of their pore surfaces. (C) 2001 Elsevier Science Ltd. All r ights reserved.