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Frequency‐Response Evidence for Parallel Diffusion Processes in the Bimodal Micropore System of an Activated Carbon
Author(s) -
Onyestyák György,
Valyon József,
Bóta Attila,
Rees Lovat V. C.
Publication year - 2002
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(200208)85:8<2463::aid-hlca2463>3.0.co;2-c
Subject(s) - chemistry , small angle x ray scattering , activated carbon , microporous material , diffusion , propane , adsorption , carbon fibers , nitrogen , analytical chemistry (journal) , carbon dioxide , sorbent , chemical engineering , ammonia , scattering , thermodynamics , chromatography , organic chemistry , physics , materials science , composite number , optics , composite material , engineering
The rates of mass transport of gases such as propane, carbon dioxide, and ammonia have been studied in an activated carbon sorbent. The frequency‐response (FR) method was used to measure these rates. Small‐angle X‐ray scattering (SAXS) and nitrogen‐adsorption isotherm at 77 K showed that the activated carbon contains small micropores with diameters around 0.64 and 0.92 nm, respectively. The FR‐rate spectra distinguished two parallel diffusion processes with different time constants, suggesting that the smaller and the larger micropores were not interconnected.