Quantitative determination of oxygen-containing functional groups in coal by FTIR spectroscopy

Fourier transform infrared (FTIR) spectroscopy is potentially a powerful tool for the characterization of coal. By considering the functional group's absorption in the FTIR spectra of coals, a suitable program for curve fitting is used to synthesize the IR spectra. The synthesis is accomplished by adding 38 absorption peaks with Gaussian shapes, the peaks are separated according to the identified functional groups. The hydroxyl concentration is measured from the absorption of 3200 cm{sup -1}, carboxylic acid group from the absorption of 1710 cm{sup -1}, and other oxygen-containing functional groups from the absorption of 1300 1000 cm{sup -1}. Three interesting relationships have been observed between the absorbencies and concentration of oxygen-containing functional groups determined by the chemical analysis. FTIR study on 18 typical Chinese coals with different ranks showed that oxygen in carboxyl, hydroxyl and other oxygen-containing functional groups decreased with increasing coal rank, and the concentration of oxygen-containing functional groups can be used for the measurement of coal rank. 9 refs., 6 figs., 2 tabs.