Table 3 Assignment of FTIR absorption bands
From: Phosphogypsum waste as additives to lime stabilization of bentonite
Bands, cm−1 | Samples | Significance |
|---|---|---|
464.4; 524.2 | Bentonite B + 8% L B + 8% L + 8% PG | Deformation of the Al-O-Si bond and deformation of the Si-O-Si bond or elongation of the Fe-O bond. |
602.4; 665.9 | PG B + 8% L + 8% PG | Asymmetric deformation of sulfate (ν4 SO4). |
627.1; 620 | Bentonite B + 8% L B + 8% L + 8% PG | Al–O and Si–O out-of-plane vibrations. |
701.2 | Bentonite B + 8% L B + 8% L + 8% PG | Si-O-Si |
803.6; 1040.1 | Bentonite B + 8% L B + 8% L + 8% PG | Elongation vibration of the Si-O bond. |
874.2; 1431.8 | B + 8% L B + 8% L + 8% PG | C-O stretching vibration of calcite. |
916.5 | Bentonite B + 8% L B + 8% L + 8% PG | Deformation of the Al-Al-OH bond. |
1156.5 | B + 8% L B + 8% L + 8% PG | Asymmetric elongation of sulfate (ν3 SO4). |
1622.4; 1689.4 | PG | Water molecule deformation vibrations (ν2 H2O). |
1650.5; 1644 | Bentonite B + 8% L B + 8% L + 8% PG | Bonds assigned to hydroxyl stretching and H–O–H bending vibrations of interlayer water molecules on montmorillonite. |
3411.7; 3556.4 | PG | Symmetrical and asymmetrical elongation of H2O (ν1 H2O). |
3673.6; 3708.2 | Bentonite B + 8% L B + 8% L+ 8% PG | Adsorbed water molecules. |