Influence of synthesis parameters on the structure of boehmite sol particles

Petrović, Rada; Milonjić, Slobodan K.; Jokanovic, Vukoman; Kostic-Gvozdenovic, Lj.; Petrovic-Prelevic, Irena; Janaćković, Djordje

doi:10.1016/s0032-5910(03)00091-3

Cited by 30 publications

(17 citation statements)

References 13 publications

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“…This process known as peptization, or deagglomeration, is usually achieved by adsorption of protons or hydroxyl ions on the surface of the particles causing electrostatic repulsion. Petrovic et al [13] have shown that textural properties, such as specific surface area, depend on the type of acid used for the peptization during the synthesis step, which means that the deagglomeration state depends on the used acid. Morgado et al [14] studied the boehmite particles' behaviour regarding peptization for samples synthesized at high (85°C) and room (25°C) temperature and for various OH/Al ratios.…”

Section: Introductionmentioning

confidence: 99%

Control of the textural properties of nanocrystalline boehmite (γ-AlOOH) regarding its peptization ability

Karouia¹,

Boualleg²,

Digne³

et al. 2013

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Kneading-extrusion is a key shaping process, especially used to prepare extrudates for catalytic applications. It usually involves several successive steps, mainly used to control textural properties such as pore diameter and pore volume of γ-alumina catalyst supports. The ability to successfully tune these properties is highly dependent on the boehmite precursor features. This work aims at understanding the influence of the peptization and neutralization steps on the textural properties of boehmite exhibiting similar crystallite size and shape but different peptization abilities. Three kinds of boehmite (low, medium and high peptization ability) obtained either by precipitation or by alkoxide hydrolysis were subjected to a peptization and neutralization steps in order to simulate the full shaping process of kneading extrusion. After peptization and neutralization, no significant changes were found in crystallite shape and size, but only in their spatial arrangement. For the boehmite exhibiting the lowest peptization ability, the particle packing seems to be frozen and no modifications result from peptization or neutralization. However for boehmite with the medium peptization ability, obtained by precipitation from the same precursors as the low peptizable sample, the particles were initially poorly organised and their spatial packing was very affected by the peptization and neutralization phases, giving a narrower pore size distribution than the synthesized powder. Though the third boehmite, obtained by alkoxide hydrolysis, was fully peptizable, this does not allow tailoring the textural properties, whatever the phase of the shaping process. Finally the partially peptizable boehmite seems to be the most versatile starting material for the control of the textural properties.

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Section: Introductionmentioning

confidence: 99%

Control of the textural properties of nanocrystalline boehmite (γ-AlOOH) regarding its peptization ability

Karouia¹,

Boualleg²,

Digne³

et al. 2013

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“…Peptization is a process in which coagulated precipitates dissolve and recrystallize to form nanoparticles with an acid or base [17]. Various metal oxide nanoparticles including boehmite are reported to be prepared by the peptization method [18,19]. Fig.…”

Section: Resultsmentioning

confidence: 99%

Hard coating films based on organosilane-modified boehmite nanoparticles under UV/thermal dual curing

et al. 2008

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“…A presença de H 2 O na atmosfera de síntese e na transformação de fase da alumina tem implicação fundamental na morfologia e polimorfismo do óxido e na ação dos aditivos no controle da microestrutura [5][6][7][8]. Uma comparação do efeito da rota de síntese na atividade do íon Ti como aditivo na alumina mostrou claramente esta diferença [9].…”

Section: Efeito Do Vapor D'água Na Síntese Pelo Método Do Precursor Punclassified

Efeito do vapor d'água na síntese pelo método do precursor polimérico da alumina contendo aditivos

Castro

Gouvêa

2005

Cerâmica

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A presença de H2O nos processos de síntese e transformação de fase da alumina tem usualmente função catalisadora, diminuindo as temperaturas dos processos e facilitando os possíveis rearranjos atômicos. Neste trabalho mostrou-se que o vapor de H2O durante a síntese pode não apenas acelerar os processos diminuindo as energias de ativação, mas também induzir diferentes formas de ação de aditivos. O estudo foi possível utilizando-se o método dos precursores poliméricos para a síntese dos pós, que permite um controle absoluto do teor de H2O na etapa de cristalização do material. Alumina contendo Mn ou Mg como aditivos foram sintetizadas na ausência de H2O e na presença de excesso controlado desta e fases diferentes para cada situação foram observadas. Uma explicação do fenômeno é descrita em função da dependência da cristalização da gama-Al2O3 na presença de H+ para compensação das vacâncias catiônicas.

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Influence of synthesis parameters on the structure of boehmite sol particles

Cited by 30 publications

References 13 publications

Control of the textural properties of nanocrystalline boehmite (γ-AlOOH) regarding its peptization ability

Control of the textural properties of nanocrystalline boehmite (γ-AlOOH) regarding its peptization ability

Hard coating films based on organosilane-modified boehmite nanoparticles under UV/thermal dual curing

Efeito do vapor d'água na síntese pelo método do precursor polimérico da alumina contendo aditivos

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