Pore Size Distribution of Activated Carbons Prepared by Activation with Chemical Agents

Abstract

The activated carbon was prepared by the following procedure;saw dust from pine was impregnated with the concentrated aqueous solution of zinc chloride, phosphoric acid and calcium chloride respectively and then heated at temperature from 400-700°C for 75 minutes.
In the case of the activated carbon with zinc chloride at 500-600°C, its pores were widely distributed in the range of radii from 1 to 5 nm.The meso-pore volume was over 70% of the total volume, about 1.4 ml/g.The specific surface area was 1500-1600 m²/g. As to the product activated with phosphoric acid at 600°C, its pore size distribution had a maximum at radii of about 1-2 nm.The volume of pores with radii of 2-5 nm was less than that of the carbon activated with zinc chloride.The total pore volume was about 1.0 ml/g and the surface area was 1270 m²/g. For the activated carbon prepared by activation with calcium chloride, its surface area and pore volume were quite small as compared with those of other specimens, 400 m²/g and 0.35 ml/g.
The pore volume obtained by mercury porosimetry was larger than that by nitrogen adsorption method, in all specimens.This result would suggest that the volume of mercury filling into the voids between the particles are regarded as the pore volume.