Pore structures and adsorption properties of fluorinated activated carbon fiber

摘要

N{sub}2 adsorption and XPS elucidated the surface states of fluorinated activated carbon fiber (F-ACF) and fluorinated carbon black. The XPS examination showed that the C-F bonds are not ionic, but covalent. The N{sub}2 adsorption isotherms ofF-ACF was of Type land the adsorption was predominant at a low P/P{sub}0 region, although the total adsorption amount of F-ACF decreased. The fluorination reduced the pore width of ACF by 0.2l nm. Only external nanographitic layers of three stackingsheets were fluorinated, considering from the crystallite size from X-ray diffraction and the chemical analysis. The increase of the pore-wall thickness by the fluorination of the nanographitic sheets agreed with the decrease of the pore width byfluorination. Adsorption isotherms of H{sub}2O, CH{sub}3OH, and C{sub}2H{sub}5OH were measured. The fluorinated ACF showed a perfect hydrophobicity. Also adsorption isotherms of CH{sub}3OH and C{sub}2H{sub}5OH on F-ACF had an S-shaped nature at the lowP/P{sub}0 region, while their adsorption isotherms of ACF were of Type I.