Fine pore mouth structure of molecular sieve carbon with GCMC-assisted supercritical gas adsorption analysis

Abstract

N 2 adsorption isotherms of molecular sieve carbon were measured at 77 K and 303 K. The Ar adsorption isotherms of molecular sieve carbon samples were also measured at 303 K. The grand canonical Monte Carlo (GCMC) simulation technique was applied to calculate the N 2 and Ar adsorption isotherms at 303 K using the ultramicropore volume determined by H 2 O adsorption. The comparative method of experimental and simulated isotherms of supercritical N 2 and Ar at 303 K gave the width of the micropore mouth of the molecular sieve carbon, which can be applied to the ultramicropore width determination for other noncrystalline porous solids.

Evaluation of carbon nanopores using large molecular probes in grand canonical Monte Carlo simulations and experiments

“…The evaluation of ultramicropores using the above-mentioned probe molecules is often unsuccessful. The adsorption of CO 2 and water under ambient conditions can be measured to evaluate ultramicropores, because the effective sizes of CO 2 and water at ambient temperatures are smaller than that of N 2 [32][33][34][35][36][37]. The measurement of He adsorption at extremely low temperatures has also been proposed as a method for the assessment of ultramicropores [38,39].…”

Supercritical Hydrogen Adsorptivity of Amorphous Carbon Mesotubes

“…The observed value of 6 kJ/mol corresponds to the calculated value for a pore width of 0.7 nm using Grand Canonical Monte Carlo (GCMC) simulations (Kowalczyk et al 2005). Since there are serious difficulties with pore structure evaluation using nitrogen adsorption for ultramicropores with widths of less than 0.7 nm (Kobori et al 2009), the estimated pore width of 0.7 nm for ACM is plausible.…”

Pore-Mouth Structure of Highly Agglomerated Detonation Nanodiamonds

“…Therefore, we need to elucidate the water-adsorbed state in the pore structure of nanodiamonds. Probe molecules nitrogen, argon, and water, among others, have been used to define the pore structure of porous adsorbent materials [18,19]. In the present study, we reveal the pore structure changes in nanodiamonds due to long-term heat treatment in vacuo by measurements of argon, nitrogen, and water adsorption and correlate them to water adsorptivity.…”

“…The pore structure of porous adsorbent materials can be described by the adsorption of specific probe molecules. The recommended values of kinetic diameters of probe molecules such as water, argon and nitrogen are 0.27 nm, 0.34 nm, and 0.36 nm [18,19]. The higher adsorption temperature of Ar (87 K) compared with that of the adsorption of nitrogen (77 K) favors the molecular diffusion in the restricted pores.…”