Catalytic activity of acid-treated montmorillonite in polar and non-polar reaction media

Rhodes, Christopher N.; Brown, R. C.

doi:10.1007/bf00811801

Cited by 77 publications

(51 citation statements)

References 8 publications

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“…The increase of the adsorbed water bands on IR spectra in the range of 4000-2500 cm −1 probably indicates a decrease of crystallite size (Figure 2a) after the treatment of Mt-T2 sample with HNO 3 acid for 108 h. Previous studies of Mt-M and Mt-T1 samples treated with HCl acid [26] showed the reduction of band intensity at 841-845 cm −1 (Al-Mg-OH), 882 cm −1 (Al-Fe-OH) and 914-926 cm −1 (Al-Al-OH), which indicates the leaching of Al 3+ , Mg 2+ and Fe 3+ cations from the octahedral sites [44][45][46][47][48][49] Leaching of the octahedral cations leads to modifications of the interaction between the octahedral and tetrahedral sheets in the 2:1 layer and, as a result, to the partial destruction of octahedral sheets. Alterations in FTIR data revealed as decreasing intensities of the bands related to octahedral Al, Fe and Mg and exchangeable Ca, Na and Mg correlate with changes in chemical composition shown above.…”

Section: Transformation Of the Montmorillonite Structure Under Acid Tmentioning

confidence: 91%

“…(Figure 1). These changes can be related with leaching of the interlayer cations (Ca 2+ and Mg 2+ ) and partial protonation of interlayer space i.e., substitution of interlayer cations with oxonium ion [44,45] because protonation of Ca-Mg montmorillonite proceeds much faster than that of Na-forms [43].…”

Section: Transformation Of the Montmorillonite Structure Under Acid Tmentioning

confidence: 99%

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Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

et al. 2017

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This paper discusses the mechanism of montmorillonite structural alteration and modification of bentonites' properties (based on samples from clay deposits Taganskoye, Kazakhstan and Mukhortala, Buriatia) under thermochemical treatment (treatment with inorganic acid solutions at different temperatures, concentrations and reaction times). Treatment conditions were chosen according to those accepted in chemical industry for obtaining acid modified clays as catalysts or sorbents. Also, more intense treatment was carried out to simulate possible influence at the liquid radioactive site repositories. A series of methods was used: XRD, FTIR, ICP-AES, TEM, nitrogen adsorption, and particle size analysis. It allowed revealing certain processes: transformation of montmorillonite structure which appears in the leaching of interlayer and octahedral cations and protonation of the interlayer and -OH groups at octahedral sheets. In turn, changes in the structure of the 2:1 layer of montmorillonite and its interlayer result in significant alterations in the properties: reduction of cation exchange capacity and an increase of specific surface area. Acid treatment also leads to a redistribution of particle sizes and changes the pore system. The results of the work showed that bentonite clays retain a significant portion of their adsorption properties even after a prolonged and intense thermochemical treatment (1 M HNO 3 , 60 • C, 108 h).

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Section: Transformation Of the Montmorillonite Structure Under Acid Tmentioning

confidence: 91%

Section: Transformation Of the Montmorillonite Structure Under Acid Tmentioning

confidence: 99%

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

et al. 2017

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“…Changes in the layer stacking and particles micromorphology results in mesopore formation [15,27]. Structural transformations are shown simplified in Fig.…”

Section: Transformation Of Montmorillonite Adsorption Properties Undementioning

confidence: 99%

“…Such changes in XRD patterns occur due to the leaching of the interlayer cations (Ca 2+ and Mg 2+ ) and partial protonation of interlayer space, i.e. substitution of interlayer cations with oxonium ion [14,15]. However many authors noted that protonation of Ca-Mg montmorillonite is much faster than Na-forms [12].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Montmorillonite Structure and Transformation of its Properties under the Treatment of Inorganic Acid Solutions

Krupskaya

Закусин

Tyupina

et al. 2016

Preprint

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Abstract:The paper discusses the mechanism of montmorillonite structure alteration and bentonites properties modification (on the example of samples from clay deposit Taganka, Kazakhstan) due to the thermochemical treatment (treatment with inorganic acid solutions at different temperatures, concentrations and reaction times). With the use of the suit of methods certain processes were distinguished: transformation of montmorillonite structure, which appears in the leaching of interlayer and octahedral cations, protonation of the interlayer and OH groups at octahedral sheets. Changes in the structure of the 2:1 layer of montmorillonite and its interlayer result in significant changes in the properties -reduction of cation exchange capacity and an increase of specific surface area. The results of the work showed that bentonite clays retain a significant portion of its adsorption properties even after the long term and intense thermochemical treatment (6M HNO3, 60°C, 108 hours)

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“…As argilas ativadas são geralmente usadas como adsorventes em indústrias de óleos vegetais, animais, vinhos e cervejas. São usadas também como catalisadores em uma série de reações orgânicas [3,4]. No entanto, o maior consumo desse material é no descoramento de óleos vegetais [5].…”

Section: Introductionunclassified

Influência do tipo de ácido usado e da sua concentração na ativação de uma argila bentonítica

Foletto

Volzone²,

Morgado

et al. 2001

Cerâmica

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ResumoA ativação ácida de uma argila tem por finalidade aumentar as suas propriedades adsortivas e catalíticas. Nesse estudo, uma amostra de argila bentonítica, proveniente da Província de Mendoza (Argentina), foi ativada com diferentes concentrações (4 e 8 N) por ácido sulfúrico e clorídrico. Para verificar a influência das concentrações e do tipo de ácido usado na ativação da argila, utilizou-se técnicas de difração de raios X, análise térmica diferencial e termogravimétrica e análise química. Os resultados mostraram que houve modificação na estrutura do material argiloso após o ataque ácido. O tratamento com ácido sulfúrico e clorídrico sobre uma mesma bentonita originou produtos com diferentes características estruturais.Palavras-chave: ativação ácida, argila, bentonita. AbstractThe clay acid activation has the purpose of increasing its adsorbent and catalytic properties. In this study, a bentonite clay sample from Mendoza (Argentine) was activated in different concentrations (4 N and 8 N)

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Catalytic activity of acid-treated montmorillonite in polar and non-polar reaction media

Cited by 77 publications

References 8 publications

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

Experimental Study of Montmorillonite Structure and Transformation of its Properties under the Treatment of Inorganic Acid Solutions

Influência do tipo de ácido usado e da sua concentração na ativação de uma argila bentonítica

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