Physicochemical Properties of Montmorillonite Interlayered with Cationic Oxyaluminum Pillars

Occelli, Mario L.; Tindwa, Robert Morley

doi:10.1346/ccmn.1983.0310104

Cited by 226 publications

(87 citation statements)

References 17 publications

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“…Thus, the structure of the Al-pillar is analogous to the polyhydroxo cation in that the bridging OH groups and H20 molecules are replaced with oxygen atoms (Jones, 1988). By using differential scanning calorimetry (DSC) and differential thermal analysis (DTA), dehydration and dehydroxylation of the polyhydroxo cations appear gradually with a maximum temperature of 500~ for water loss (Occelli and Tindwa, 1983;Pinnavaia et al, 1984). Thus, the Al-pillars are probably hydrous aluminum oxides.…”

Section: Sorption Of Heavy Metal Ions By Hal-and Ai-mx80mentioning

confidence: 99%

Sorption of Heavy-Metal Cations by Al and Zr-Hydroxy-Intercalated and Pillared Bentonite

Matthes

Madsen

Kahr

1999

Clays and clay miner.

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Abstract--The sorption of Cd, Cu, Pb, and Zn ions by Na-rich bentonite, AI and Zr-pillared Na-rich bentonite (A1-MX80, Zr-MX80), the uncalcined hydroxy-intercalated precursors (HA1, HZr-MX80), and commercial Al-pillared bentonite EXM 534 was investigated. Experiments were conducted in ultrapure water and artificial leachate with varying pH. The experiments were performed over periods to 30 wk. Sorption characteristics were described with one and two-site Langmuir isotherms. The non-exchangeable quantities of heavy metals were determined by fusion of the sorbents after ion exchange with ammonium acetate.The sorption of Cd, Cu, Pb, and Zn by bentonite was dominated by cation exchange. In artificial leachate, the sorption was reduced due to competition with alkali and alkaline-earth cations. The sorption of Cu, Zn, and Pb at pH 4.9 and Cd at pH 6.9 by A1 and Zr-hydroxy-intercalated and pillared MX80 was governed also by cation exchange. In contrast, the sorbed quantities of Zn at pH 6.9 exceeded the cation exchange capacity (CEC) of HA1, HZr, A1, Zr-MX80, and EXM 534 and were partially nonexchangeable. The increase of the sorption of Zn with pH and its independence of the ionic strength of the solution at neutral pH suggest a complexation of Zn ions to surface hydroxyl groups of the intercalated A1 and Zr-polyhydroxo cations and pillars. This complexation is the dominating sorption mechanism. Removal of dissolved Zn from solution with time is attributed to surface precipitation. Al-hydroxy and pillared bentonites are considered potential sorbents of Zn ions from neutral pH aqueous solutions, such as waste waters and leachates.

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Section: Sorption Of Heavy Metal Ions By Hal-and Ai-mx80mentioning

confidence: 99%

Sorption of Heavy-Metal Cations by Al and Zr-Hydroxy-Intercalated and Pillared Bentonite

Matthes

Madsen

Kahr

1999

Clays and clay miner.

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“…The heat treatment of intercalated montmorillonite (A) at 673 K resulted in the release of water and caused the hydroxyaluminum oligocations to transform into aluminum oxide pillars (Pinnavaia, 1983;Occelli and Tindwa, 1983). This resulted in a small decrease in the doo~ distance.…”

Section: Resultsmentioning

confidence: 99%

Sorption Properties of Carbon Composite Materials Formed from Layered Clay Minerals

Putyera

Bandosz

Jagiełło

et al. 1994

Clays and clay miner.

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Abstract--The sorption properties of carbon-composite materials based on montmoriUonite and hydrotalcite matrices have been studied using nitrogen adsorption isotherms and inverse gas chromatography. Carbon composite materials derived from both types of inorganic precursors contain pore structure accessible for adsorbate molecules. Adsorption capacity per unit mass of these composite adsorbents is larger in the case of hydrotalcite than in montmorillonite-based materials. Exposing these materials to ambient conditions results in their hydration. Subsequent water removal by heating under vacuum increases nitrogen adsorption capacity, which is explained by the opening of the adsorption space. The water content of hydrated samples and its effect on adsorption capacity is greater for the case of hydrotalcite-based materials. No direct relationship between carbon content and adsorption properties of the materials studied is observed.

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“…A aplicação de esmectitas pilarizadas como adsorventes é sugerida, por estes materiais apresentarem pilares que mantêm separadas as camadas da estrutura da argila e propiciam que as dimensões de suas cavidades se tornem bem superiores às das zeólitas [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] . Neste trabalho foi feita uma avaliação sobre o uso de esmectita pilarizada na adsorção de Cu(II), Ni(II) e Co(II), sendo selecionada uma amostra de esmectita da região noroeste do estado do Pará, que foi submetida à pilarização mista com poliidroxicátions de zircônio e titânio.…”

Section: Introductionunclassified

Aplicação de Zr/Ti-PILC no processo de adsorção de Cu(II), Co(II) e Ni(II) utilizando modelos físico-químicos de adsorção e termodinâmica do processo

Guerra¹,

Airoldi²,

Lemos³

et al. 2008

Quím. Nova

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Recebido em 26/6/07; aceito em 10/8/07; publicado na web em 26/2/08 APPLICATION OF Zr/Ti-PILC IN THE ADSORPTION PROCESS OF Cu(II), Co(II) and Ni(II) USING ADSORPTION PHYSICO-CHEMICAL MODELS AND THERMODINAMICS OF THE PROCESS. The aim of this investigation is to study how Zr/Ti-PILC adsorbs metals. The physico-chemical proprieties of Zr/Ti-PILC have been optimized with pillarization processes and Cu(II), Ni(II) and Co(II) adsorption from aqueous solution has been carried out, with maximum adsorption values of 8.85, 8.30 and 7.78 x10 -1 mmol g -1 , respectively. The Langmuir, Freundlich and Temkin adsorption isotherm models have been applied to fit the experimental data with a linear regression process. The energetic effect caused by metal interaction was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant.Keywords: adsorption isotherms; metals; Zr/Ti -pillared clay. INTRODUÇÃOA adsorção de metais por superfícies minerais é um processo reconhecidamente importante que controla a biodisponibilidade dos metais em ambientes aquáticos [1][2][3][4][5][6][7][8][9] . O tratamento clássico de efluentes contendo metais envolve processos físico-químicos de precipitação, troca iônica, adsorção e extração por solventes, sendo mais utilizado o de precipitação, que é inadequado no tratamento de grandes volumes de efluentes, devido à baixa eficiência e elevados custos 10 . Neste caso, é mais recomendado o uso de recursos naturais sem tratamento prévio, como solos argilosos ferruginosos ricos em substân-cias húmicas 11 e, também, materiais naturais quimicamente modificados, como exemplos zeólitas naturais impregnadas com materiais magnéticos 12,13 e argilas modificadas por processo de pilarização ou intercalação. Tais materiais se enquadram no grupo de materiais porosos, desenvolvidos pela engenharia de materiais, com ampla aplicação em catálise heterogênea 14 e como adsorventes [15][16][17][18][19][20][21] .Com a evolução das pesquisas em busca de novos materiais que fossem utilizados como adsorventes, surgiram os materiais meso e microporosos, em particular as zeólitas ou peneiras moleculares, que atuam efetivamente com alto poder adsortivo, provocado por suas propriedades texturais. No decorrer do avanço das pesquisas surgiram as argilas pilarizadas com diversos polioxicátions, que produziram resultados satisfatórios em processos de adsorção. Vários metais pesados foram testados em meio líquido com adsorventes minerais quimicamente modificados, sendo que os resultados obtidos mostraram que as argilas pilarizadas são bastante eficientes em processos de adsorção 9-13 . Diversos estudos comprovam a eficiência das argilas em processos adsortivos e catalíticos, sendo que as argilas mais comumente empregadas em estudos de adsorção pertencem ao grupo da esmectita, principalmente a montmorilonita [14][15][16][17][18] .Estudos de adsorção de cobre realizados com amostras de esmectitas pilarizadas com pilare...

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Physicochemical Properties of Montmorillonite Interlayered with Cationic Oxyaluminum Pillars

Cited by 226 publications

References 17 publications

Sorption of Heavy-Metal Cations by Al and Zr-Hydroxy-Intercalated and Pillared Bentonite

Sorption of Heavy-Metal Cations by Al and Zr-Hydroxy-Intercalated and Pillared Bentonite

Sorption Properties of Carbon Composite Materials Formed from Layered Clay Minerals

Aplicação de Zr/Ti-PILC no processo de adsorção de Cu(II), Co(II) e Ni(II) utilizando modelos físico-químicos de adsorção e termodinâmica do processo

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