Thermo-XRD-analysis of montmorillonite treated with 1,4-diaminoanthraquinone

Orly Keidar, Isaak Lapdes, Shlomo Shoval, Shmuel Yariv

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Charcoals formed during the thermo-XRD-analysis of montmorillonite (MONT) complexes with the dye 1,4-diaminoanthraquinone (DAAQ) were investigated by using curve-fitting calculations. Five saturated dye solutions were prepared (i) in distilled water and (ii-v) in 0.1, 0.5, 1.0, and 2.0 molar HCl. Two series of dye-clay complexes were prepared by using clay suspensions of 0.6 %and of 0.006 % labeled first and second series, respectively. Five dye-clay complexes were prepared of each series by adding 25 mL of dye solution to 25 mL of clay suspension. There is no free dye in complexes of the first series, but those of the second series, which were synthesized with a high ratio between dye and clay, contain non-adsorbed dye even after five washings. Complexes of the first series are loaded with very small amounts of molecular and protonated DAAQ (5-24 mmol DAAQ per 100 g clay), and their spacings are 1.25-1.54 nm suggesting the presence of tactoids with protonated or molecular DAAQ lying parallel to the clay layers. No carbon analyses were performed to the second series complexes. In addition to tactoids with spacing of 1.32 nm, they contain tactoids with spacings of 1.81-1.96 nm, suggesting that intercalated DAAQ are lying perpendicular to the clay layers. Three types of intercalated charcoal are identified in both series during the thermal analysis, one type with a low thermal stability and two types with high thermal stabilities. Charcoals of the second series complexes preserve the geometry of the original complexes up to high temperatures.

Original languageEnglish
Pages (from-to)177-187
Number of pages11
JournalJournal of Thermal Analysis and Calorimetry
Issue number1
StatePublished - 17 Sep 2014

Bibliographical note

Publisher Copyright:
© 2014 Akadémiai Kiadó.


  • Basal spacings
  • Carbon content
  • Charcoal
  • Diaminoanthraquinone-montmorillonite
  • Organo-clays
  • Tactoids
  • Thermo-XRD-analysis


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