ADSORPTION OF WATER-VAPOR ON ACTIVE CARBONS - ESTIMATION OF PORE WIDTH

The successive adsorption and desorption paths of water vapor on active carbons at 30°C have been measured and it was suggested that the micropore structures of active carbons are more closely reflected in the desorption branch than in the adsorption one. Based on these results, the empirical equations for the estimation of the average pore width L have been proposed. L (nm) = -α( ndes n0.95) + β [1] and L (nm) = γ log( ΔS S) + δ, [2] where ndes is the adsorption amount of water vapor at the beginning point of the linear range of plots in the steep fall of the desorption branch and n0.95 is that at P P0 - 0.95. ΔS (= Sdes - Sads) is the magnitude of the hysteresis loop and S is that of the adsorption branch (Sads) or the desorption one (Sdes) in the range of 0 ≦ P P0 ≦ 0.95, respectively, α, β, γ, and δ are the constants (>0). © 1990.