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Title: Gas/vapor adsorption in imogolite: A microporous tubular aluminosilicate

Journal Article · · Langmuir; (United States)
DOI:https://doi.org/10.1021/la00028a029· OSTI ID:6250790
; ;  [1];  [2];  [3];  [4]
  1. Univ. of New Mexico, Albuquerque (United States)
  2. Univ. of New Mexico, Albuquerque (United States) Los Alamos National Lab., NM (United States)
  3. Sandia National Lab., Albuquerque, NM (United States)
  4. Univ. of New Mexico, Albuquerque (United States) Sandia National Lab., Albuquerque, NM (United States)

Imogolite is a structurally microporous tubular aluminosilicate with one-dimensional pore channels of a single diameter that may be varied between 0.6 and 1.0 nm depending on composition. With proper processing, imogolite tubes may be synthesized and aligned into macroscopic, densely-packed arrays yielding a porous solid exhibiting a high degree of microporosity which is oriented in a single dimension as demonstrated via SEM and TEM. [sup 29]Si MAS NMR indicates that with proper synthesis, essentially pure tube bundles may be obtained with very low concentrations of amorphous (nontubular) impurities as compared to purified natural imogolite. The microporous structure of natural and synthetic imogolite has been investigated by nitrogen adsorption at 77 K as a function of outgassing temperature. For synthetic samples, pore volumes are approximately 0.2 cm[sup 3]/g and the average pore diameter for the 100% Si samples is approximately 0.7 nm and is approximately 0.9 nm for the 50% Si/50% Ge sample. CO[sub 2] and CH[sub 4] adsorption at 273 K is measured over the pressure range of 0-800 Torr and uptake is influenced by tube diameter even though the surface area of the two synthetic samples is similar. 24 refs., 12 figs., 1 tab.

DOE Contract Number:
AC04-76DP00789
OSTI ID:
6250790
Journal Information:
Langmuir; (United States), Vol. 9:4; ISSN 0743-7463
Country of Publication:
United States
Language:
English