Molecular resolution analysis of .alpha.-FeOOH-dispersed activated carbon fibers

Abstract

The irregularity of the micropore walls of {alpha}-FeOOH-dispersed activated carbon fibers ({alpha}-FeOOH-ACF) was examined by the adsorption of planar, spherical, and zigzag molecules at 303 K and powder x-ray diffraction at room temperature. {alpha}-FeOOH-ACF gave more diffuse x-ray diffraction patterns with high background than the original ACF, indicating that the surface of {alpha}-FeOOH-ACF has a more amorphous structure than that of the original ACF. {alpha}-FeOOH can adsorb more planar molecules and fewer zigzag molecules than the original ACF. The relationships between the logarithm of the monolayer capacity from the BET plot and the logarithm of molecular area determined from both molecular weight and liquid density at 303 K were linear, indicative of fractal pore walls. The surface fractal dimension, D{sub 8}, of the micropore wall was determined from the linear plots; the dispersion of ultrafine {alpha}-FeOOH increased the D{sub 8} value. The relationships between the logarithm of the micropore volume from the DR plots and the logarithm of molecular volume were linear; the apparent exponents determined from the plots are greater than the D{sub 8} values, suggested slightly heterogeneous micropore size distribution.