PCS-577
Pyridine sorption isotherms of Argonne Premium coals: dual-mode sorption and coal
microporosity
Green, T.K.; Selby, T.D.
Energy & Fuels
1994
8(1)
213-218
Pyridine sorption isotherms were determined for three Argonne Premium coals at
50[degree]C. It is proposed that the isotherms are best interpreted in terms of a
dual-mode sorption model originally developed to explain sorption of vapors into glassy
polymers. This model considers two different population of sorbed gas; one is dissolved
into the polymer and is described by Henry's law (i.e., sorption is linear with pressure)
while the second population is considered to occupy unrelaxed free volume (micropores)
within the polymer and is described by a Langmuir isotherm. We propose that the
high-pressure linear portion of the pyridine isotherms for two coals represent dissolution
of pyridine in the coal matrix and that the low-pressure regions represent primarily
adsorption into micropores. The pyridine-extracted coals all show a dramatic increase in
intercept value, suggesting that pyridine extraction creates new micropores. O-alkylation
with bulky alkyl groups yield reduced intercepts, which correlate with the size of the added
alkyl group. It is suggested that the added alkyl groups occupy micropores in the
structure. 26 refs., 7 figs., 1 tab.
1. Upper Freeport,PA (UF)
2. Wyodak-Anderson, WY (WY)
3. Illinois #6 (IL)
4. Pittsburgh #8 (PIT)
5. Pocahontas #3 (POC)
6. Blind Canyon,UT (UT)
7. Lewiston-Stockton, WV (WV)
8. Beulah-Zap, ND (ND)