Example 6
A mixture obtained by mixing 100 parts by mass of granular coal pitch having a softening point of 280° C. as an organic material with 0.3 part by mass of tris(acetylacetonato)yttrium was fed into a melt extruder, where it was melted and mixed at a melting temperature of 320° C., and spun at a discharge rate of 20 g/min to obtain a pitch fiber. The pitch fiber was subjected to an infusibilization treatment by heating for 54 minutes, to 354° C. from ambient temperature in the air at a rate of 1 to 30° C./minute, to obtain an infusibilized pitch fiber as an activated carbon precursor. The yttrium content in the activated carbon precursor was 0.06% by mass.
The activated carbon precursor was activated by conducting a heat treatment at an atmospheric temperature of 950° C. for 60 minutes, while continuously introducing a gas having a CO2 concentration of 100% by volume into an activation furnace, to obtain an activated carbon of Comparative Example 6. In the activated carbon, the pore volume A of pores with a size of 1.0 nm or less was 0.429 cc/g, the pore volume B of pores with a size of 3.0 nm or more and 3.5 nm or less was 0.000 cc/g, the yttrium content was 0.15% by mass, and the fiber diameter was 18.2 μm.
