Intercalation of kaolinite under hydrothermal conditions

Vempati, R. K.; Mollah, M. Yousuf A.; Reddy, G. Rajendra Kumar; Cocke, David L.; Lauer, H. V.

doi:10.1007/bf00353104

Cited by 25 publications

(14 citation statements)

References 23 publications

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“…It can be concluded that the H 2 PO 4 − anions has been intercalated into the interlayers of LDHs successfully, and the intercalation ratio could be calculated based on the following formula :

α = \frac{I_{true(003 true)}}{I_{true(003 true)} + I_{0 true(003 true)}} \times 100 %

where α is the intercalation ratio, I 0(003) is the intensity of (003) diffraction peak in LDHs at 2 θ = 11.58°; and I (003) is the intensity of (003) diffraction peak in M‐LDHs at 2 θ = 7.3°, where is the diffraction peak of LDH molecules after intercalation. According to the formula above, the intercalation ratio could reach about 96.4% after the intercalation of H 2 PO 4 − anions.…”

Section: Resultsmentioning

confidence: 99%

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Flammability and thermal behavior of polypropylene composites containing dihydrogen phosphate anion‐intercalated layered double hydroxides

Zhang

Liu

et al. 2014

Polymer Composites

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Dihydrogen phosphate anion‐intercalated layered double hydroxides (M‐LDHs) was prepared by modification of Mg‐Al‐CO32− layered double hydroxides (LDHs) with anion exchange procedure. The structure of the M‐LDHs was characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscope (TEM). Polypropylene (PP)/LDHs and PP/M‐LDHs composites were prepared by melt compounding. The morphology of PP composites was investigated by TEM and XRD, which demonstrated that M‐LDHs could be well dispersed in PP matrix to form a nano‐scale exfoliated structure. Thermogravimetric analysis showed that thermal stability of PP composites was improved by the presence of LDHs and M‐LDHs. The flammability of PP composites was characterized by limited oxygen index, vertical burning test (UL‐94), FTIR, and cone calorimeter test, and the result showed the fire performance were significantly improved after the addition of LDHs and/or M‐LDHs which can remarkably decrease the heat release rate, total heat release, and the fire performance index. It was proposed that the lamellar structure of LDHs can block the heat, dilute the flammable gases and decrease the temperature, while the replaced H2PO4− into LDHs molecules can enhance the charred layer formation during burning procedure. Inductively coupled plasma mass spectrometer analysis showed that most phosphorus remained in the char layer, suggesting the replaced H2PO4− in LDHs molecules mainly function in the condensed phase. POLYM. COMPOS., 36:2230–2237, 2015. © 2014 Society of Plastics Engineers

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α = \frac{I_{true(003 true)}}{I_{true(003 true)} + I_{0 true(003 true)}} \times 100 %

Section: Resultsmentioning

confidence: 99%

“…It can be concluded that the H 2 PO 4 2 anions has been intercalated into the interlayers of LDHs successfully, and the intercalation ratio could be calculated based on the following formula [29]:…”

Section: Resultsmentioning

confidence: 99%

Flammability and thermal behavior of polypropylene composites containing dihydrogen phosphate anion‐intercalated layered double hydroxides

Zhang

Liu

et al. 2014

Polymer Composites

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“…A new method for DMSO intercalation into kaolinite under hydrothermal conditions was reported by Vempati et al (54). Yields of over 90% could be achieved in 20 min upon heating 1 g of kaolinite in 10 cm 3 DMSO in a Parr bomb at 150 • C. The FTIR analysis showed the disappearance of the Al OH deformation band at 941 cm −1 .…”

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confidence: 96%

Vibrational Spectroscopy of Intercalated Kaolinites. Part I.

Horváth

Kristóf

Frost

2010

Applied Spectroscopy Reviews

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The industrial application of kaolinite is closely related to its reactivity and surface properties. The reactivity of kaolinite can be tested by intercalation; that is, via the insertion of low-molecular-weight organic compounds between the kaolinite layers resulting in the formation of a nano-layered organo-complex. Although intercalation of kaolinite is an old and ongoing research topic, there is limited knowledge available on the reactivity of different kaolinites and the mechanism of complex formation, as well as on the structure of the complexes formed. Grafting and incorporation of exfoliated kaolinite in polymer matrices and other potential applications can open new horizons in the study of kaolinite intercalation.This article attempts to summarize (without completion) the most recent achievements in the study of kaolinite organo-complexes obtained with the most common intercalating compounds such as urea, potassium acetate, dimethyl sulphoxide, formamide, and hydrazine using vibrational spectroscopy combined with X-ray powder diffraction and thermal analysis.

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“…The SieO bending vibration was indicated by absorption bands at 1163.11e1008.8 cm À1 , while the SieO stretching vibrations were observed at 798.56e644.25 cm À1 . The presence of the AleO bending vibration was revealed by the band at 914.29 cm À1 , while absorptions at 538.16e432.07 cm À1 correspond to the AleOeSi skeletal vibrations (Njoya et al, 2006;Vempati et al, 1996). After the adsorption of Ni(II) and Mn(II) ions from the binary solution by UAB, there were shifts in the frequency of absorption from 3443.05 cm À1 to 3446.91 cm À1 , 2360.95 cm À1 to 2347.45 cm À1 , 1631.83 cm À1 to 1629.9 cm -1 and the disappearance of the band at 3416.05 cm À1 which indicated the use of the negatively charged eOH group for binding of positively charged metal ions to the surface of UAB.…”

Section: Characterization Of Adsorbentmentioning

confidence: 98%

Potential of a low-cost bentonite for heavy metal abstraction from binary component system

Akpomie

Dawodu

2015

Beni-Suef University Journal of Basic and Applied Sciences

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BentoniteHeavy metals Equilibrium Kinetics Thermodynamics a b s t r a c t A low-cost and easily obtainable Nigerian bentonite (UAB) was utilized for the removal of heavy metals (Nickel and Manganese) from a binary system. The bentonite was used without chemical modification in order to keep the process cost low. A Fourier transform infrared spectrum was utilized to determine the surface functional groups responsible for adsorption. Scanning electron microscopy revealed a porous surface of UAB. Batch adsorption methodology was applied to study the effect of pH, initial metal ion concentration, adsorbent dose, adsorbent particle size, ligands (citric acid and EDTA), contact time and temperature on the adsorption process. The isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Scatchard isotherm. Scatchard plot analysis revealed the heterogeneous nature of UAB. Kinetic parameters were tested using the pseudo-first order, pseudo-second order, intraparticle and film diffusion models. The presence of film diffusion mechanism was found to play a major role in the adsorption process. Thermodynamic studies revealed an endothermic, spontaneous and physical adsorption process.Importantly, over 90% of both metal ions were desorbed from the bentonite in desorption studies. The results indicated the potential of UAB as a low-cost and eco-friendly adsorbent for the removal of Ni(II) and Mn(II) ions from aqua media.

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Intercalation of kaolinite under hydrothermal conditions

Cited by 25 publications

References 23 publications

Flammability and thermal behavior of polypropylene composites containing dihydrogen phosphate anion‐intercalated layered double hydroxides

Flammability and thermal behavior of polypropylene composites containing dihydrogen phosphate anion‐intercalated layered double hydroxides

Vibrational Spectroscopy of Intercalated Kaolinites. Part I.

Potential of a low-cost bentonite for heavy metal abstraction from binary component system

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