Thermal stability and hot-stage Raman spectroscopic study of Ca-montmorillonite modified with different surfactants : a comparative study
Sun, Zhiming, Park, Yuri, Zheng, Shuilin, Ayoko, Godwin A., & Frost, Ray L. (2013) Thermal stability and hot-stage Raman spectroscopic study of Ca-montmorillonite modified with different surfactants : a comparative study. Thermochimica Acta, 569, pp. 151-160.
Three long chain cationic surfactants were intercalated into Ca-montmorillonite through ion exchangeand the obtained organoclays were characterized by X-ray diffraction (XRD), high resolution thermo-gravimetric analysis (TG) and Raman spectroscopy. The intercalation of surfactants not only changes thesurface properties of clay from hydrophilic to hydrophobic but also greatly increases the basal spacing ofthe interlayers based on XRD analysis. The thermal stability of organoclays intercalated with three sur-factants (TTAB, DTAB and CTAB) and the different arrangements of the surfactant molecules intercalatedinto Ca-montmorillonite were determined by TG-DTG analysis. A Raman spectroscopic study on the Ca-montmorillonite modified by three surfactants prepared at different concentrations provided the detailedconformational ordering of different intercalated long-chain surfactants under different conditions. Thewavenumber of the antisymmetric stretching mode is more sensitive than that of the symmetric stretch-ing mode to the mobility of the tail of the amine chain. At room temperature, the conformational orderingis more easily affected by the packing density in the lateral model. With the increase of the temperature,the positions of both the antisymmetric and symmetric stretching bands shift to higher wavenumbers,which indicates a decrease of conformational ordering. This study offers new insights into the struc-ture and properties of Ca-montmorillonite modified with different long chain surfactants. Moreover, theexperimental results confirm the potential applications of organic Ca-montmorillonites for the removalof organic impurities from aqueous media.
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|Item Type:||Journal Article|
|Keywords:||Organoclay, Ca-montmorillonite, TG, XRD, Raman spectroscopy|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > PHYSICAL CHEMISTRY (INCL. STRUCTURAL) (030600) > Structural Chemistry and Spectroscopy (030606)|
|Divisions:||Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute of Health and Biomedical Innovation
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Copyright Owner:||Copyright 2013 Elsevier B.V.|
|Copyright Statement:||This is the author’s version of a work that was accepted for publication in Thermochimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Thermochimica Acta, [VOL 569, (2013)] DOI: 10.1016/j.tca.2013.07.022|
|Deposited On:||09 Sep 2013 22:57|
|Last Modified:||11 Oct 2015 20:23|
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