Phenolic-resin-derived activated carbons

A novel binderless preparative route is described for the production of phenolic-resin-derived carbons for use as catalyst supports and adsorbents. The carbons can be produced in a wide variety of physical forms ranging from simple granules to large monolithic structures. The fully interconnected macropore structure of the carbons, which derives from the interconnected voids between the primary resin particles, can be precisely controlled to give a mean macropore size of between around 1 and 50 microns. This then gives rise to very high permeabilities that can be orders of magnitude higher than conventional porous support materials. The microstructure of the carbons appears to derive from the void spaces between small (similar to 4 nm) spherical resin domains generated during the initial polymer curing step which gives rise to a very narrow pore distribution with a mean pore size of approximate to 0.8 nm. This is in contrast to earlier studies that suggested the pores reflected voids in a tangled ribbon structure. The high purity of the carbons (total metals content of <500 ppm) has also allowed a precise determination of the activation kinetics. This has shown that the as-produced carbon comprises two domains - a low reactivity skeleton formed from the small resin domains, and a higher reactivity carbon that appears to partially fill the skeletal pore structure and that is selectively removed during activation. (C) 1998 Elsevier Science B.V. All rights reserved.