Adsorption and mobility of water molecules and organic substances in carbon adsorbents Communication 3. Dependence of self-diffusion coefficients of adsorbed molecules of water and methanol on size of micropores in active carbons and on degree of pore filling

Abstract

1. The self-diffusion coefficients (SDCs) of water and methanol molecules, measured by the pulse-gradient NMR method, are independent of the time of observation A. The previously noted dependence of the SDC on A is explained by the large error of SDC measurements at short observation times. 2. The SDC of adsorbed water and methanol molecules increases with increasing size of the micropores. In activated carbons with a mean half-width of the micropores smaller than 0.66 nm, the SDC of adsorbed methanol at 298°K is lower than the SDC of water, but in activated carbon with larger pores, the SDC of methanol is higher than that of water.