Abstract
The quality of adsorbents used for commercial adsorption samplers or for previous empirical studies of adsorption sampling was surveyed with regard to specific surface area and pore size distribution derived from N adsorption isotherms. Five kinds of grain coconut-shell active carbons, 3 kinds of sheet-type active carbon preparations, 2 kinds of grain silica gels and 3 kinds of porous polymer beads were submitted to N2 adsorption isotherms measurements. The grain active carbons had BET-specific surface areas ranging from 812 to 1309 m2/g, sheet-type active carbons from 348 to 625 m2/g, silica gels from 332 to 637 m2/g and porous polymers from 320 to 491 m2/g. Transformation of the isotherms into V-t plots showed that the surface areas of active carbons were almost entirely borne by micropores with radii less than 3.54Å, but the surface areas of silic agels and porous polymers o were more borne by pores with radii larger than 3.54Å. These surface properties should be referred to in the design and handling of adsorption sampling devices.
