BASIC CONCEPTS AND AN OVERVIEW - Foundations of Nanotechnology: Pore Size in Carbon-Based Nano-Adsorbents - page 91

be dependent on a controlled gasification process at temperatures ranging from
800o 1000°C. In their activation procedure they applied the NLDFT method and
showed that a greater degree of activation led to a widening of the pore size dis-
tribution from 2.8 to 7.0 nm. They contribute this broadening to a decrease in the
number of micro domains. This phenomenon was coupled with an increase in the
peak pore size (from 0.44 nm to 1.86). The adsorption data and sub sequential
pore size analysis was confirmed by NMR. The chemical activation process on
the other hand involves the mixing of a carbon precursor with a chemical activat-
ing agent typically KOH, NaOH, H 3 PO 4 or ZnCl 2 [1, 127, 129, 142].
1.2.2.11 ADSORPTION INDUCED MOLECULAR TRAPPING (AIMT)
IN MICROPOROUS MEMBRANE MODEL
Model and simulation schemes and Principles of the DCV-GCMD numerical ex-
periment in microporous membrane is illustrated in Fig. 1.5.

FIGURE 1.5 Schematic representation of DCV-GCMD method.

In our simulations the membrane thickness stands as one unit cell: l = 2:5 nm.
Our numerical experiment consists in reproducing an experimental set-up used for
permeability measurements, as illustrated in below detailed. For that purpose we
use the DCV-GCMD method with high and low fugacity reservoirs are imposed
at each end of the membranes. This allows the application of periodic boundary
conditions. While the fugacities in these reservoirs are controlled by means of
Grand Canonical Monte Carlo simulation, molecular motions are described using
Molecular Dynamics simulation. Once the system has reached the steady-state
regime, the molar flux J is estimated by counting the number of molecules N
crossing the membrane of cross section S during a time interval :