The effect of organic cation content on the interlayer spacing, surface area and porosity of methyltributylammonium-smectite

To examine the effect of the organic cation content on the porous structure of an organosmectite, a sodium-rich smectite (NaS) with a cation exchange capacity (CEC) of 1.08 mol kg−1 was intercalated with methyltributylammonium cations (MTBA+) equivalent to 0.2, 0.4, 0.6, 0.8, and 1.0 times the CEC. The prepared methyltributylammonium smectite (MTBAS) samples were examined by the X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and low temperature nitrogen adsorption-desorption techniques. The basal spacing of the MTBASs, d(0 0 1), obtained from the XRD data, widens from 1.21 to 1.58 nm as the content of MTBA+ increase from 0 to 1.0 time the CEC. The FTIR spectra of the MTBASs display the typical bands related to NaS plus extra bands attributable to the presence of MTBA+. As the extent of intercalation increases the specific surface area (S) increases from 61 to 106 m2 g−1 and specific micro-mesopore volume (V) from 0.11 to 0.25 cm3 g−1. The increase in the S and V values shows that the intercalated MTBA+ cations simply act as pillars to hold the 2:1 layers of the NaS permanently apart, and therefore, the intercalation ends up with the formation an adsorptive-type organosmectite. Otherwise, it would be formed an organic partition nanophase and also a sorptive-type organosmectite.