Turkey has one of the largest lignite deposits in Europe with total estimated reserves of 11.5 billion tons. For effective development and utilization of these coal resources, there is need for scientific investigation into its chemical structure, which is lacking today. In this work, we report the information on structural parameters of Turkish coals in the Manisa Soma and Mugla Yatagan region determined by X-ray diffraction, Raman, and FTIR spectroscopy. The average lateral sizes (La), stacking heights (Lc) and interlayer spacing (d002) were calculated from XRD data. Aromaticity ratios ranged from 62% to 78%. The FTIR spectra of the demineralized coals contained absorptions due to stretching vibrations of -OH, aliphatic -CH2- and -CH3 groups and aromatic ring C=C and aromatic -CH structures. The Raman spectra were deconvoluted into 4 bands (G, GR + VL + VR, D and S). The areas of GR, VL and VR bands were grouped together and treated as one band representing the overlap between the G and D bands. The full width at half maximum (FWHM) of the G band ranged from 92 to 98 cm-1 which was far greater than that recorded for carbon nanotubes and highly oriented pyrolytic graphite of about 15-23 cm-1. This feature indicated a low degree of crystallinity the studied coal samples, confirming indications from the d002 values from the XRD analysis. The increases in the ID/IG ratio indicated relative increases in the concentrations of aromatic rings having six or more fused benzene rings. This resulted from the dehydrogenation of hydroaromatics and the growth of aromatic rings in the coals during coalification reactions. While the ID/IG ratio of coals from Soma region changed between 1.0 and 1.2 the ID/IG ratio for the Yatagan-Eskihisar coal was found to be as 1.5.

Structural characterization of Turkish coals by X-ray diffraction, Raman and FTIR Spectroscopy

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.