EVOLUTION OF MICROPORE STRUCTURE OF ACTIVATED-CHARCOAL CLOTH

A series of microporous charcoal cloths of burn-offs between 20 and 92% have been prepared and studied by means of nitrogen, isobutene, methanol, and water adsorption isotherm measurements. The results indicate that at a level of burn-off of about 50%, the polarity of the surface falls to a minimum while the micropore volume, when expressed in terms of the same initial weight of carbon, reaches a maximum. At higher levels of burn-off both pore widening and pore narrowing occur. In addition, significant shrinkage of the carbon structure occurs at all stages of burn-off. The results are discussed in terms of a simple model, and it is concluded that densification of the carbon structure during activation exerts a significant influence on the evolution of the micropore structure.