The I.R. Spectra of Dimethyl Sulfoxide Adsorbed on Several Cation-Substituted Montmorillonites

Abstract

Abstract--The i.r. spectra (4000-1200 cm 1) are obtained for several homoionic montmorillonite films on which various amounts of dimethyl sulfoxide (DMSO) were adsorbed. Analyses of these spectra indicate that H-and natural-montmorillonite-DMSO complexes contain an intercalated layer of physisorbed DMSO while transition metal cation substitutedmontmorillonite-DMSO complexes possess both physi-and chemisorbed DMSO in their interlamellar spaces. The latter species involve coordination of DMSO molecules with the exchangeable cations by their oxygen atoms. Most of the interlamellar water is replaced by DMSO as the latter molecules penetrate the interlameUar spaces. Heat-treating transition metal cation substituted-montmorillonite-DMSO complexes at 120~ for 48 hr results in both the desorption of physisorbed DMSO and the retention of intercalated monolayers involving DMSO-transition metal cation coordination. A water-sensitive, reversible color change (tan to light purple) is produced by either desiccating over P~O.~ or heat-treating at 120~ the cobalt-montmorillonite-DMSO complex. Interpretation of the visible spectra suggests that Co2+-cations undergo changes from octahedral to tetrahedral coordination during desiccation or heating. Band assignments are made for the clay complexes using the assignments for related gases, liquids, and crystals.

Adsorption Mechanism and Structure of the Montmorillonite Complexes with (CH3)2XO (X=C, and S), (CH3O)3PO, and CH3–CN Molecules

“…Although the DMSO-montmorillonite complexes have not been studied by IR spectrometry in this paper, previous works showed that the DMSO molecules interact with the interlayer cation through the oxygen atom of the sulfoxide group (25,26). …”

Comparison of sample preparation methods for the Fourier-transform infrared analysis of an organo-clay mineral sorption mechanism

“…The transport of organic contaminants through porous media, and the computer modeling of that transport, are of great importance for the prediction of groundwater quality at present (1). Germane to this is the characterization of interactions between mineral surfaces and organic compounds that are implicated as environmental contaminants (2)(3)(4). Through the use of Fourier transform infrared (FT-IR) spectroscopy, the mechanism of an organo-mineral sorption interaction can be determined by an analysis of the direction and magnitude of band shifts and intensity variations when the spectrum of the organic compound is compared against that of the organo-mineral complex (5)(6)(7).…”

Liquid‐Phase Synthesis of Hydrophilic Luminescent Carbon Dots Using Porous Silica as a Nanotemplate

“…[ 18,19 ] Weak but well‐pronounced bands at 2920 and 3010 cm −1 (Figure 3a) are caused by symmetrical and asymmetrical stretching vibrations of CH bonds in DMSO molecules. [ 20 ]…”