Characterisation and Al-pillaring of smectites from Miles, Queensland (Australia)

Ten montmorillonite-type clay samples from Miles, Queensland, Australia, have been characterised using XRD, ICP-AES and infrared spectroscopy. The Na-exchanged sample, DH-30, was used for pillaring with Al by exchange with an Al(NO)/NaOH solution with an approximate OH/Al molar ratio of 2.2. The XRD pattern for the expanded smectite provided evidence that the Na/Al polymer exchange had occurred. XRD patterns for the raw sample, the Na-exchanged clay and the Al exchanged clay resulted in d-spacing of 15.09, 15.73 and 17.42 Å, respectively. Calcination at 600 °C of the Al-smectite led to a minor decrease in basal spacing to approximately 16.5 Å. The effect of temperature on the Al-expanded smectite was also apparent when the d-spacing of an air-dried sample (19.44 Å) was compared to that of an oven-dried (60°C) sample (17.42 Å). This difference was due to the loss of water molecules from the Al outer sphere of hydration.