Molecular Structure of Dimethyl Sulfoxide Intercalated Kaolinites

Abstract

Upon the intercalation of kaolinite with DMSO, new Raman bands at 3660, 3536, and 3501 cm-1 are observed for the low-defect kaolinite and at 3664, 3543, and 3509 cm-1 for the high-defect kaolinite. An additional band at 3598 cm-1 was observed for the high-defect kaolinite. The band at 3660 cm-1 was assigned to the inner-surface hydroxyls hydrogen bonded to the SO group. The other three bands are attributed to the hydroxyl stretching frequencies of water in the intercalation complex. The hydroxyl deformation region is characterized by one intense band in both the FTIR and Raman spectra at 905 cm-1. Significant changes in the Raman spectra of the intercalating molecule are observed. Splitting of the C−H symmetric and antisymmetric stretching vibrations occurs. Two Raman bands at 2917 and 2935 cm-1 and four bands at 2999, 3015, 3021, and 3029 cm-1 are observed. The in-plane methyl bending region shows two Raman bands at 1411 and 1430 cm-1. The DRIFT spectra show complexity in these regions. The SO stretching region shows bands at 1066, 1023, and 1010 cm-1 upon intercalation with DMSO for the low-defect kaolinite and 1058, 1028, and 1004 cm-1 for the high-defect kaolinite. The 1058 cm-1 band is assigned to the free monomeric SO group and the 1023 and 1010 cm-1 bands to two different polymeric SO groups. Bands attributed to the C−S stretching vibrations, the in-plane and out-of-plane SO bending and the CSC symmetric bends all move to higher frequencies upon intercalation. It is proposed that intercalation with DMSO depends on the presence of water and that the additional bands at 3536 and 3501 cm-1 are due to the presence of water in the intercalate.

Encapsulated Urea-Kaolinite Nanocomposite for Controlled Release Fertilizer Formulations

“…Similarly, our conclusion also agrees with [47][48][49] whose works reported IR bands at 3538 and 3502 cm −1 . Moreover, the peak at 3657 cm −1 correspond to the inner-surface hydroxyl hydrogen bonded to the S=O group as referred to elsewhere [49].…”

Square Wave Voltammetric Determination of Lead(II) Ions Using a Carbon Paste Electrode Modified by a Thiol‐Functionalized Kaolinite

“…The absorption bands of kaolinite at 3698, 3670 and 3652 cm À1 correspond to interlayer hydroxyl stretching while the band observed at 3620 cm À1 is ascribed to the stretching vibrations of the inner hydroxyl group [17,36,37]. After intercalation with DMSO, the position of the 3698 cm À1 vibration band is not affected, while the 3670 and 3652 cm À1 bands are perturbed by the formation of hydrogen bonds between DMSO and the interlamellar hydroxyl groups of kaolinite giving new bands at 3542 and 3502 cm À1 [23,30,38]. For the thiol-functionalized kaolinite, the internal OH stretching vibration at 3620 cm À1 is still observed.…”

Characterization of Sr2+uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

“…In order to examine the effect of expanding the interlayer space of kaolinite on the amount of adsorbed Sr 2+ , the clay was intercalated with dimethylsulfoxide, DMSO ((CH 3 ) 2 SO). Intercalation of DMSO in kaolinite provides a method for the incorporation of alkali and alkaline metal salts into the kaolinite structure by replacement of DMSO [31]. DMSO molecules are bound into the kaolinite structure by hydrogen bonding of the S=O to the gibbsite-like hydroxyls and by a coordination of the sulfur to the oxygens of the siloxane surface [31] .…”

“…Intercalation of DMSO in kaolinite provides a method for the incorporation of alkali and alkaline metal salts into the kaolinite structure by replacement of DMSO [31]. DMSO molecules are bound into the kaolinite structure by hydrogen bonding of the S=O to the gibbsite-like hydroxyls and by a coordination of the sulfur to the oxygens of the siloxane surface [31] . Intercalation of DMSO within the kaolinite lamellae caused a change in position of the primary 001 and 002 reflections to higher d hkl values.…”