Effect of Swelling on the Infrared Absorption Spectrum of Montmorillonite

Abstract--From swelling and surface area measurements, it was found that the swelling of a montmorillonite depends linearly on the fraction of its layers that fully expand in water and that this fraction, in turn, depends linearly on the b dimension of the unit cell. Therefore, swelling is a linear function of the b dimension. However, the specific surface area of a montmorillonite is a linear function of its b dimension only if no partially expanded layers exist. It was also found that the distance between fully expanded layers at a given applied pressure is the same for all montmorillonites.

“…The former corresponds to Si---O absorption, whereas, the latter corresponds to H-O-H (bending) absorption. Lerot and Low (1976) also showed theoretically that…”

Section: Methods IVmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Relation Between Swelling, Surface Area and b Dimension of Na-Montmorillonites

Odom

Low

1978

“…Such a displacement could have been caused by relaxation of the wet sample or by its shrinkage as water evaporated from it. It is noteworthy that they observed a rapid increase in b-dimension at the water content at which a sudden rearrangement of the clay particles is now known to occur (Lerot and Low, 1976). Undoubtedly, this rearrangement affects the consistency of the sample.…”

Section: Resultsmentioning

confidence: 98%

Change of b-Dimension with Swelling of Montmorillonite

Ravina

Low

1977

Abstract--The effect of swelling on the b-dimension of Na-saturated, Upton, Wyoming montmorillonite was re-examined using powdered silicon as an internal standard. After being corrected with reference to the internal standard, the b-dimension did not increase through the entire range of swelling as reported previously. It increased up to a water content of ~ 3.0 g/g montmorillonite and remained constant thereafter. However, the diffraction peak of the internal standard shifted towards lower angles at higher water contents. This shift was attributed to a relaxation of the wetter samples away from the knife edge of the diffractometer. Presumably, a similar relaxation occurred in the earlier study and was responsible for the apparent increase in b-dimension at water contents above ~ 3.0 g/g.The b-dimension of Upton montmorillonite saturated with different cations was determined using powdered silicon and a colloidal quartz impurity as internal standards. The water content at maximal swelling decreased as the b-dimension increased.

“…Most IR studies of clay minerals refer to transmission measurements (Lerot and Low 1976;Sposito et al 1983) and concern the effects on the transmittance spectra of clays modified by various processes such as intercalation, pillaring or adsorption of organic molecules. However, transmittance experiments present certain problems, such as the high absorptivities associated with minerals that make the recording of good quality transmission spectra difficult unless the mineral is less than 5 ixm thick (Wihlborg 1989).…”

Section: Introductionmentioning

confidence: 99%

Infrared Reflectance Study of Thermally Treated Li- and Cs-Montmorillonites

Karakassides

1997

Abstract--The structure of Li-and Cs-montmorillonites was studied using infrared (IR) reflectance spectroscopy. The spectra of heat-treated clays between 80 and 220 ~ were analyzed by Kramers-Krtinig inversion in order to obtain the optical and dielectric properties of the clays. The analysis revealed the transverse-optic (TO) and longitudinal-optic (LO) components of the asymmetric stretching vibration of Si-O-Si bridges. Major differences, in particular the systematic development of new bands, were found in the Li-montmorillonite LO and TO spectra with increasing temperature. These changes were attributed to the migration of the Li-cations into the layer structure.