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

摘要

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 iwth increasing activation time and temeprature. 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 invlove enhanced phydical adosorption 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.