Diffusion barriers in the kinetics of water vapor adsorption/desorption on activated carbons

被引:108
作者
Harding, AW
Foley, NJ
Norman, PR
Francis, DC
Thomas, KM
机构
[1] Univ Newcastle Upon Tyne, Dept Chem, No Carbon Res Labs, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[2] CBD, Salisbury SP4 0JQ, Wilts, England
关键词
D O I
10.1021/la971317o
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The adsorption of water vapor on a highly microporous coconut-shell-derived carbon and a mesoporous wood-derived carbon was studied. These carbons were chosen as they had markedly different porous structures. The adsorption and desorption characteristics of water vapor on the activated carbons were investigated over the relative pressure range p/p(o) = 0-0.9 for temperatures in the range 285-313 K in a static water vapor system. The adsorption isotherms were analyzed using the Dubinin-Serpinski equation, and this provided an assessment of the polarity of the carbons. The kinetics of water vapor adsorption and desorption were studied with different amounts of preadsorbed water for set changes in pressure relative to the saturated vapor pressure (p/p(o)). The adsorption kinetics for each relative pressure step were compared and used to calculate the activation energies for the vapor pressure increments. The kinetic results are discussed in relation to their relative position on the equilibrium isotherm and the adsorption mechanism of water vapor on activated carbons.
引用
收藏
页码:3858 / 3864
页数:7
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