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 Al13 by exchange with an Al(NO3)3/NaOH solution with an approximate OH/Al molar ratio of 2.2. The XRD pattern for the expanded smectite provided evidence that the Na/Al13 polymer exchange had occurred. XRD patterns for the raw sample, the Na-exchanged clay and the Al13-exchanged clay resulted in d-spacings of 15.09, 15.73 and 17.42 Å, respectively. Calcination at 600 °C of the Al13-smectite led to a minor decrease in basal spacing to approximately 16.5 Å. The effect of temperature on the Al13-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 Al13 outer sphere of hydration.