An
in-depth investigation was carried out on five Chinese coals
using a range of advanced analytical techniques focused specifically
on extracting structural parameters. Detailed investigations were
carried out using Fourier transform infrared spectroscopy (FTIR),
Raman spectroscopy, and X-ray diffraction followed by peak deconvolution
and data analysis. Correlations were established for parameters determined
from different techniques. The FTIR data showed good linear relationships
between the apparent aromaticity (f
a(FTIR)) and (R/C)u with the
H/C atomic ratio for all coals under investigation. These results
indicate that FTIR spectroscopy coupled with appropriate data analysis
can be successfully used to determine aromaticity and the coal rank.
Raman spectroscopy data showed a negative linear relationship between
the GL fraction and H/C ratio; no well-defined relationship
was observed between other band fractions and the H/C ratio. The decrease
of A
D/A
G with
increasing H/C ratio indicates the growth of aromatic rings; i.e.,
the structure of the sample was closer to that of graphite. This result
is in good agreement with the decrease of apparent aromaticity (f
a(FTIR)) as determined by the FTIR spectroscopy.
A good linear relationship was observed between the structural parameters
(f
a(X‑ray) and R
X‑ray) determined with X-ray and coal rank (represented
by the H/C ratio). Even though the correlations among parameters derived
from three techniques showed a similar trend and were consistent with
each other, FTIR, and X-ray diffraction techniques were found to be
better than Raman spectra to characterize coal maturity. These findings
have led to a simplified coal model based on the complementary information
from different techniques on various aspects of the coal structure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.