The bands at 3615 cm -1 and 3445 cm -1 for all the samples are attributed to stretching vibrations, while the band at 1635 cm -1 is assigned to bending vibrations of -OH groups from water molecules . The bands corresponding to the AlAlOH and AlMgOH bending vibrations are observed at 915 and 880 cm -1 , respectively. A broad band at 1,000 cm -1 is related to the stretching vibrations of the Si-O groups, while the band at 790 cm -1 and 1100 cm -1 belong to asymmetric stretching vibration or bending vibration of Si-O-Si bonds . The band at 621 cm -1 is assigned to the Al-O and Si-O couple from the plane vibrations . It can be observed that the clay, after modification, differs from the pristine MMT. Spectra of the modified clays reveal additional absorption bands, absent for the pristine M, originating from the terpenes, confirming their presence in the aluminosilicate. The peaks at ca. 2952 cm -1 are assigned to -CH3 groups of pinene and limonene, and a small peak at 1462 cm -1 to the vibrations of the skeletal C-H bond of these groups. Additionally, geminal methyl groups (1384 and 1366 cm -1 ) ) can be noticed in samples with pinene.