Thermal analytic study of the adsorption of crystal violet by laponite

Yariv, S.; Müller-Vonmoos, Max; Kahr, G.; Rub, A.

doi:10.1007/bf01911677

Cited by 18 publications

(3 citation statements)

References 14 publications

(12 reference statements)

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“…40 Due to these properties, laponite is mainly used in industry as a rheological modifier and film former. However, laponite and surface modified laponite have also been used for adsorption of dyes 41,42 surfactants 43 and biomolecules. 44 In the present study, laponite elementary disc crystals and laponite stacked discs resulting from the exfoliation of raw laponite and forming a colloidal suspension have been used as nanobuilding blocks.…”

Section: Introductionmentioning

confidence: 99%

Laponite and hybrid surfactant/laponite particles processed as spheres by spray-drying

2009

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Laponite elementary disc crystals dispersed in water in the presence or absence of non-ionic Brij58 surfactant have been used as nanobuilding blocks to form laponite and laponite/surfactant spherical particles by spray-drying. The size distribution of the spherical spray-dried particles ranges from 70 to 1000 nm (average size about 220 nm). Although raw laponite (RL) was almost totally exfoliated in water, the spray-dried spherical particles were found partially delaminated and stable when spread into water. Based on a full characterization by several techniques such as dynamic light scattering, scanning and transmission electron microscopies, X-ray diffraction, thermal analyses, nitrogen volumetric sorption and solid-state multi-nuclear NMR studies, a mechanism has been proposed to explain the formation of the spherical micron size particles: a face-to-face and edge-to-edge stacking of the elementary disc crystals leads to the formation of few-layer laponite platelets that aggregate within the restricted volume of water droplets during the drying stage. In the presence of Brij58, elementary disc crystals are covered by surfactant molecules adsorbed on their surface. As a consequence, surfactant molecules fill the interlayer space to form spherical Brij58/laponite nanocomposite particles. These spray-dried laponite and Brij58/laponite spherical particles present a high potential for sorption applications. IntroductionDuring recent decades the interest towards nanoparticles has mainly increased because of their properties such as surface reactivity that are different from those of the bulk material. However, decreasing the size brings disadvantages such as toxicity 1 and/or manipulation difficulties. 2 Nanoparticles are interesting, not only for their unique properties, but also for their potential to be used as nanobuilding blocks. Interest in nanobuilding blocks is growing as they have been recognized to be basic units for the elaboration of hierarchically-organized materials by self-assembling processes. 3,4 As there are various types of inorganic nanobuilding blocks and several ways to link them together, the resulting materials are numerous. 5 Moreover, this strategy allows a better control of the structure of the final material and offers an easier shape modelling.Materials resulting from nanobuilding blocks can be used in different application domains such as catalysts, 6,7 varnishes and adhesives; 8 or marginally in two-terminal circuit device nano-applications 9,10 or non-volatile random access memory. 11 Most nanobuilding units are nanocrystals that can be classified according to their one-, two-or three-dimensionalities 12 such as tubes, wires, plates, 13-15 multipods, crosses, stars. 16 These different dimensionalities lead to materials with various morphologies such as films, 17 fibres, 18,19 mushroom-like particles, 20 spheres, 21,22 or monoliths. 23 In order to control the self-assembly process of nanoobjects for the elaboration of hierarchically organized materials, several techniques have been i...

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Section: Introductionmentioning

confidence: 99%

Laponite and hybrid surfactant/laponite particles processed as spheres by spray-drying

2009

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“…The adsorption of triphenylmethane dyes (crystal violet, methyl green) on montmorillonite was studied extensively by Margulies and Rozen (1986), Yariv et al (1989), Rytwo et al (1993Rytwo et al ( , 1995Rytwo et al ( , 1996a, and Schramm et al (1997). Cationic surface-active agents like alkylammonium ions and alkyl trimethylammonium ions interact strongly with clay minerals (Lyklema, 1994;Xu and Boyd, 1995;Ijodo and Pinnavaia, 1998).…”

Section: Introductionmentioning

confidence: 99%

Influence of Organic and Inorganic Salts on the Coagulation of Montmorillonite Dispersions

Penner

Lagaly

2000

Clays and clay miner.

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Abstracts-The colloidal state (stable, coagulated, or gel-like) and the theological properties of Na-rich montmorillonite (Wyoming) dispersions are strongly influenced by organic cations. This effect is shown for homologous organic cations: alkyl trimethylammonium ions, paraquat, diquat, alkyl bispyridinium ions, and the triphenylmethane dyes crystal violet, methyl green, and tris (tri-methylammonium phenyl) methane chloride. The critical coagulation concentrations, cK, are small (often < 1 mmol/L) because the cations are enriched in the Stern layer and influence the solvent structure near the surface. The strong adsorption of the counterions at the clay-mineral surface causes CK values to increase with the solid content. Charge reversal (recharging) of the particles was observed with the longer chain alkyl trimethylammonium ions, dodecyl bispyridinium ions, and crystal violet. Other cations reduced the electrophoretic mobility to zero but positive particle charges were not observed.The plastic viscosity increased sharply at the critical coagulation concentration and showed a minimum slightly below cK, which was caused by the electroviscous effect. Yield values were developed at concentrations above CK. In most cases, yield values reached a plateau where the amount of organic cations was -0.5 mmol/g, i.e., about half of the cation-exchange capacity. The cK values decreased with increasing hydrophobicity of homologous compounds, but the yield value showed maxima at intermediate chain lengths. The yield value of several 0.5% dispersions was high, e.g., dodecyl trimethylammonium ions, 71 Pa; paraquat, 100 Pa; diquat, 42 Pa; hexyl bispyridinium ions, 53 Pa (vs. Ca 2 § 0.2 Pa; AP +, 0.7 Pa). The storage modulus as a function of the number of organic cations changed in a similar way as the yield value, and high values were observed (e.g., dodecyl trimethylammonium ions, hexyl bispyridinium ions: 1000 Pa, paraquat: >4000 Pa). Thus, dispersions with high viscosity, yield value, and pronounced viscoelasticity are obtained by coagulating Na-rich montmorillonite dispersions with organic cations.

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“…Chichester a) To correlate evolution of gases such as Hz, HF or HC1 with structural changes of the minerals and to establish the mechanism and kinetics of these changes [1][2][3][4][5][6][7]; b) To use the gases or their condensates to reconstruct the geochemical history of the samples [8,9]; c) To assist in the determination of the mineralogical composition of argillaceous rocks [10][11][12]; d) To monitor reactions that occur on clay surfaces [13][14][15][16]; e) To assess the impact that clay volatiles and the corresponding condensates may have on their organic [17][18][19] and inorganic [20][21][22][23] environments.…”

Section: -4466/97/$ 5 O0 9 1997akaddmiai Kiad6 Budapest John Wimentioning

confidence: 99%

The nature of clay volatiles and condensates and the effect on their environment

Heller-Kallai

1997

Journal of Thermal Analysis

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When clays are heated, a mass loss occurs due to the evolution ofvolatiles. Most of these are water vapour, but in addition minor amounts of a complex assemblage of other species are liberated. The corresponding condensates are colloidal suspensions. The composition of the volatiles and condensates and the release patterns of the gases are reviewed. The nature of the assemblages varies from one clay to another and depends on the thermal regime. Both volatiles and condensates are very reactive. Their reactivity persists even after prolonged storage. They act as acid catalysts in reactions with organic matter and decompose calcite and other carbonates. Condensates were found to etch the surfaces of quartz crystals and to dealuminate and partly destroy an Al-rich faujasite (zeolite). Possible implications of reactions of clay volatiles and condensates for natural processes are discussed.

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Thermal analytic study of the adsorption of crystal violet by laponite

Cited by 18 publications

References 14 publications

Laponite and hybrid surfactant/laponite particles processed as spheres by spray-drying

Laponite and hybrid surfactant/laponite particles processed as spheres by spray-drying

Influence of Organic and Inorganic Salts on the Coagulation of Montmorillonite Dispersions

The nature of clay volatiles and condensates and the effect on their environment

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