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Hickey, Leisel; Kloprogge, J. Theo; Frost, Ray L.

doi:10.1023/a:1004800822319

Cited by 124 publications

(55 citation statements)

References 13 publications

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“…Quando naturais esses minerais estão principalmente associados a rochas metamórfi cas. Entretanto, podem ocorrer em depósitos salinos, o que demonstra que altas temperaturas e pressões não são absolutamente necessárias para sua formação [1]. Os HDLs foram sintetizados pela primeira vez em 1933 por Feitknetch, baseado na precipitação controlada de soluções aquosas contendo cátions metálicos com uma solução alcalina [2].…”

Section: Introductionunclassified

Síntese de hidróxidos duplos lamelares do sistema Cu, Zn, Al-CO3: propriedades morfológicas, estruturais e comportamento térmico

Santos

Corrêa

2011

Cerâmica

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ResumoHidrotalcitas são argilas aniônicas, também conhecidas como Hidróxidos Duplos Lamelares (HDLs) e possuem estrutura semelhante ao mineral brucita. Os HDLs do sistema Cu, Zn, Al-CO 3 foram sintetizados em condições que favorecem a formação de cristais pequenos e de elevada área superfi cial. A caracterização foi feita por difração de raios X, análise termogravimétrica, espectroscopia na região do infravermelho e microscopia eletrônica de varredura. A síntese foi feita pelo método de coprecipitação em pH variável, utilizando sulfatos de cobre e zinco, soluções de alumínio e solução de hidróxido sódio. Os difratogramas de raios X mostram que os compostos sintetizados possuem alta cristalinidade; a intensidade e a largura dos picos comprovam que os materiais se apresentam bem organizados e com empilhamento das lamelas. Os espectros de infravermelho apresentaram bandas associadas ao ânion carbonato presente na região interlamelar dos HDLs. Palavras-chave: hidróxidos duplos lamelares, hidrotalcitas, argilas aniônicas. Abstract Hydrotalcite-like compounds are anionic clays, also known as layered double hydroxides (LDH),

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Section: Introductionunclassified

Síntese de hidróxidos duplos lamelares do sistema Cu, Zn, Al-CO3: propriedades morfológicas, estruturais e comportamento térmico

Santos

Corrêa

2011

Cerâmica

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“…Hydrothermal treatment is generally employed to promote crystal growth [12] or achieve a gel to crystallite conversion [13]. In an LDH, all the cations occupy octahedral sites.…”

Section: Layered Double Hydroxides (Ldhsmentioning

confidence: 99%

Solution decomposition of the layered double hydroxide of Co with Fe: Phase segregation of normal and inverse spinels

Britto

Kamath

Ravishankar

2008

Journal of Colloid and Interface Science

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The nitrate-intercalated layered double hydroxide of Co with Fe decomposes on hydrothermal treatment to yield an oxide residue at a temperature as low as 180 • C. The oxide product is phase segregated into a Co 3 O 4 -type normal spinel and a CoFe 2 O 4 -type inverse spinel. Phase segregation is facilitated as decomposition in a solution medium takes place by dissolution of the precursor hydroxide followed by reprecipitation of the oxide phases. In contrast, thermal decomposition takes place at 400 • C. This temperature is inadequate to induce diffusion in the solid state whereby phase segregation into the thermodynamically stable individual spinels is suppressed. The result is a single-phase metastable mixed spinel oxide. This is rather uncommon in that a hydrothermal treatment yields thermodynamically stable products where as thermal decomposition yields a metastable product.

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“…15 The bands below 1000 cm −1 are due to M-O vibration modes (Mg-O, Al-O) in the brucite layer, 27 the peak at 451 cm −1 is assigned to Mg-O, and the peak at 551 cm −1 is assigned to Al-O vibration. The FT-IR spectra in Figure 7c showed the expected characteristic peaks of deprotonated carboxylic groups for DC-MgAl-LDH at 2914 and 2580 cm −1 (CH 2 stretching mode), at 1592, 1560 and 1413 cm −1 (CO asymmetric and symmetric stretching mode), at 1467 cm −1 (CH 2 scissoring mode), and at 991 cm −1 (CH 2 rocking mode) comparing with those peaks observed for 1,10-decanecidarboxylic acids.…”

Section: 2223mentioning

confidence: 99%

Step-wise Anion-Exchange in Layered Double Hydroxide Using Solvothermal Treatment

Lee¹,

Rhee²,

Jung

2005

Bulletin of the Korean Chemical Society

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Synthetic layered double hydroxides (LDHs), [Mg 4 Al 2 (OH) 12 ]CO 3 ·nH 2 O, were prepared in the submicron size of plate-like polycrystals. Anion-exchange reactions with various linear dicarboxylic acids were performed to produce LDH/organic hybrid materials by solvothermal treatment in toluene. X-ray powder diffraction spectra for the products indicated that the interlayer spacings of LDHs remarkably changed, up to 20 Å when 1,10-decanedicarboxylic acid anions were intercalated as an organic guest. Dicarboxylates-LDHs samples could be also re-exchanged consecutively with other dicarboxylic acids or carbonate without serious destruction of layer structure under the scanning electron microscopic observation.

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Cited by 124 publications

References 13 publications

Síntese de hidróxidos duplos lamelares do sistema Cu, Zn, Al-CO3: propriedades morfológicas, estruturais e comportamento térmico

Síntese de hidróxidos duplos lamelares do sistema Cu, Zn, Al-CO3: propriedades morfológicas, estruturais e comportamento térmico

Solution decomposition of the layered double hydroxide of Co with Fe: Phase segregation of normal and inverse spinels

Step-wise Anion-Exchange in Layered Double Hydroxide Using Solvothermal Treatment

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