Table 3 Infrared spectral absorption peaks of coal.
From: Functional group characteristics of coal treated with clean biomass surfactant via FTIR spectroscopy
Wavenumber/cm− 1 | Spectral Peak Assignment |
|---|---|
900 ~ 700 | This wavenumber range is mainly due to the out-of-plane bending vibration of various substituted aromatic hydrocarbons. |
1300 ~ 1000 | This wavenumber range is mainly due to the stretching vibration of C-O, and the characteristic absorption peak in this region is quite complex, mainly including the C-O bonds of phenols, alcohols, ethers, and esters. |
1450 ~ 1350 | This region is mainly for asymmetric and symmetric deformation vibrations of alkanes, with characteristic absorption peaks at 1440 cm− 1 and 1370 cm− 1. |
Near 1600 cm− 1 | This region is mainly for the C = C framework vibrations and stretching vibrations of aromatic and polycyclic aromatic layers. |
3000 ~ 2800 | This region is mainly for the stretching vibrations of fatty hydrocarbons, and this absorption band has two characteristic absorption peaks at 2920 cm− 1 and 2850 cm-1, representing the asymmetric and symmetric stretching vibrations of alkane C-H. |
3650 ~ 3200 | This region is mainly for the absorption of hydrogen bonds between -OH molecules in coal, with the characteristic absorption peak at around 3420 cm− 1. The intensity and width of the peak are large, making it a strong absorption peak. |
3650 ~ 3600 | This region is mainly for the stretching vibration of free -OH, with a low intensity and a sharp peak shape. The characteristic absorption peak position is around 3620 cm-1. |
