Non-aggressive pillaring of clays with zirconium acetate. Comparison with alumina pillared clays

Gandı́a, Luis; Toranzo, R.; Vicente, M.A.; Gil, Antonio

doi:10.1016/s0926-860x(99)00041-1

Cited by 25 publications

(6 citation statements)

References 47 publications

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“…6. This value is similar to the size of a zirconia polyoxocation (i.e., $2 nm 35,66 ) that is presumably present in the precursor solutions. This observation suggests that about one monolayer of zirconia polyoxocations was deposited onto the substrate per deposition cycle.…”

Section: Coupling Of the Growth Of Mmt And Sol-gel Zro 2 Layerssupporting

confidence: 54%

Layer-by-layer assembly of sol–gel oxide “glued” montmorillonite-zirconia multilayers

et al. 2010

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This paper reports the layer-by-layer synthesis and growth kinetics of a new class of nanostructured multilayers consisting of montmorillonite (MMT) nanoclays ''glued'' by sol-gel oxides, such as zirconia (ZrO 2 ) and tin oxide (SnO 2 ), {MMT x -(sol-gel oxide)} n . The multilayers possess an ordered layer structure with tunable nanoscale periods of thickness. Systematic investigation of growth kinetics revealed unique underlying film growth mechanisms. The growth of the MMT and sol-gel ZrO 2 layers is strongly coupled. For fresh aqueous ZrO 2 precursors, the growth rates of sol-gel ZrO 2 layers on MMT surfaces as functions of time and precursor concentration do not follow the standard mass transfer or interfacial reaction controlled kinetic models. Furthermore, the growth of the sol-gel oxide layers on MMT surfaces is self-limited to a maximum thickness of $50-60 nm. These observations suggest a surface-mediated growth of sol-gel oxide layers on MMT surfaces, and such growth is likely influenced or controlled by electrostatic interactions. For the aged precursors, the growth mechanism differs; the growth of sol-gel oxide layers is controlled by hydrodynamics and follows the Landau-Levich model. These new findings on detailed growth kinetics, which have been difficult to observe and quantify via the synthesis of more prevailing polyelectrolyte-based multilayers, significantly advance the general understanding of the layer-by-layer electrostatic assembly. Overall, layer-by-layer assembly of multilayers using sol-gel oxides, instead of polyelectrolytes, as both adhesive and functional components in the structure, is a new concept of nanoscale fabrication, which can lead to the development of a broad range of inorganic nanostructured films. The mechanical properties and potential applications of this new class of multilayers are briefly discussed.

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Section: Coupling Of the Growth Of Mmt And Sol-gel Zro 2 Layerssupporting

confidence: 54%

Layer-by-layer assembly of sol–gel oxide “glued” montmorillonite-zirconia multilayers

et al. 2010

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“…The speci c surface area is maintained or even slightly increased when calcining the intercalated solids. Recently, when studying clays intercalated with Zr acetate oligomers, we also found an increase in the speci c surface area during the calcination of the intercalated precursors which was due to the opening of the clay porosity by elimination of the organic moieties of the pillars (Toranzo et al, 1998;Gandṍa et al, 1999). Although a progressive collapse of the pillars is expected when the temperature is increased, simultaneously, the organic part of the complexes is eliminated.…”

Section: Fig 8 Evolution Of the Specific Bet Surface Areas Ofmentioning

confidence: 87%

Influence of the Ti precursor on the properties of Ti–pillared smectites

et al. 2001

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The pillaring of smectites (two saponites and a montmorillonite) with various Ti precursors was studied. The minerals were intercalated with ‘classical ’ Ti precursors, such as titanium tetrachloride and titanium tetraethoxide, and also with new precursors, such as solutions of titanium tetraisopropoxide in acetic acid, or titanium (bis (ethylacetoacetato) diisopropoxide) in acetone. A complete characterization of the intercalated solids was carried out and a comparison of the properties of the solids as a function of the precursors used in the intercalation established. The influence of the severe conditions in which the intercalation with Ti oligomers is usually carried out (low pH and/or high temperature) on the properties of the intercalated solids was analysed. Intercalation with TiCl4 and Ti(EtO)4 strongly affected the structure of the clays, not by acid attack on the octahedral sheet, but mainly by disaggregation of particles. Ti(isop)4 was found to be less aggressive for the clays, while Ti(etacet)2(isop)2 did not form pillared solids but organo-clays, and therefore was of no use as a pillaring agent. The solids were thermally stable up to 300°C, showing a high specific surface area.

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“…ZRA is used in very different applications. In materials processing, besides its influence on the viscosity of the suspension 41 or its use as a precursor of zirconium 42 in sol− gel or catalysis applications, it is also used as a depletioninduced stabilizer of colloidal suspensions, 43 including carbon nanotube suspensions. 44 Because ZRA controls the growth of ice crystals without any other additives or particles, 10 the depletion properties cannot account for its ice-structuring properties.…”

Section: Influence Of the Zirconium Acetate Concentrationmentioning

confidence: 99%

Ice-Structuring Mechanism for Zirconium Acetate

2012

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The control of ice nucleation and growth is critical in many natural and engineering situations. However, very few compounds are able to interact directly with the surface of ice crystals. Ice-structuring proteins, found in certain fish, plants, and insects, bind to the surface of ice, thereby controlling their growth. We recently revealed the ice-structuring properties of zirconium acetate, which are similar to those of ice-structuring proteins. Because zirconium acetate is a salt and therefore different from proteins having ice-structuring properties, its ice-structuring mechanism remains unelucidated. Here we investigate this ice-structuring mechanism through the role of the concentration of zirconium acetate and the ice crystal growth velocity. We then explore other compounds presenting similar functional groups (acetate, hydroxyl, or carboxylic groups). On the basis of these results, we propose that zirconium acetate adopts a hydroxy-bridged polymer structure that can bind to the surface of the ice crystals through hydrogen bonding, thereby slowing down the ice crystal growth.

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Non-aggressive pillaring of clays with zirconium acetate. Comparison with alumina pillared clays

Cited by 25 publications

References 47 publications

Layer-by-layer assembly of sol–gel oxide “glued” montmorillonite-zirconia multilayers

Layer-by-layer assembly of sol–gel oxide “glued” montmorillonite-zirconia multilayers

Influence of the Ti precursor on the properties of Ti–pillared smectites

Ice-Structuring Mechanism for Zirconium Acetate

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