Acid activation of a palygorskite with HCl: Development of physico-chemical, textural and surface properties

Suárez, M.; González, L.V.Flores; Vicente, M.A.; Pozas, José María Martín

doi:10.1016/0169-1317(95)00007-q

Cited by 192 publications

(74 citation statements)

References 17 publications

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“…As quantidades de Ca +2 , Na + e K + que foram removidas pelo tratamento correspondem aos cátions trocáveis que estão presentes nas amostras. No entanto, uma quantidade considerável desses elementos permanece nas amostras ativadas devido à presença de impurezas, principalmente o feldspato, que é insolúvel em soluções ácidas e que contém esses cátions [9]. Observou-se também uma importante redução dos cátions octaédricos (alumínio, ferro e magnésio) com a ativação.…”

Section: Resultsunclassified

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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Section: Resultsunclassified

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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“…Each talc-like ribbon alternates with channels along the fiber axis 2 . The palygorskite has the theoretical formula: Si 8 Mg 5 O 20 (OH) 2 (OH 2 ) 4 .4H 2 O, which was first proposed by Bradley [3][4][5] . However, the chemical composition of these mineral clays varies within certain limits according to their origin.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, acid treatment have been used for increasing the surface area of clay minerals and for obtaining from these minerals solids with a high numbers of acid centers, properties that influence the application of these materials in descolourization, adsorption and catalysis in reactions in which catalysis with acidic properties are requerid 10 . 4 .nH 2 O [3] . The natural clay dried at 25°, and ground was sieved entirely on 200 mesh sieve.…”

Section: Introductionmentioning

confidence: 99%

“…Considerable amounts of Al +3 can replace Mg +2 in the octahedral sheet. Thus, depending on the degree of isomorphous substitution, the ideal palygorskite rich in magnesium or aluminum would be: Si 8 (Mg 5-3x Al 2x ) O 20 (OH) 2 (OH 2 ) 4 .4H 2 O, whose structure contains three forms of water in its structure: zeolitic water, coordinated and structural water 6 . In addition to aluminum, other cations may replace magnesium, albeit of a less extensive form.…”

Section: Introductionmentioning

confidence: 99%

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Effects of acid treatment on the clay palygorskite: XRD, surface area, morphological and chemical composition

Xavier

Santos

et al. 2014

Mat. Res.

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The palygorskite is an aluminum-magnesium silicate that has a fibrous morphology. Their physicochemical characteristics are the result of high surface area, porosity and thermal resistance which make it an attractive adsorbent. Its adsorption capacity can be increased through chemical reactions and/or heat treatments. The objective of this work is to verify the effects of acid activation on the palygorskite, treated with HCl at 90 °C at concentrations of 2, 4 and 6 mol L -1 in 2 and 4 hours, with clay/acid solution ratio 1 g 10 mL -1 and characterized by techniques: XRF, XRD and surface area. A significant increase in specific surface area was observed in the sample treated with HCl at the concentration 6 mol L -1 . The changes were more pronounced at stricter concentrations of acidity, with decreasing intensity of reflection of the clay indicated in the XRD. These changes were confirmed in the XRF with the leaching of some oxides and with increasing concentration of SiO 2 .

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“…Internal structure will be broken and the gap will be closed reducing specific surface area when thermal treatment temperature exceeds 750°C [11]. Acid activation may increase attapulgite specific surface area, but excessive acid concentrations lead to a decrease in the specific surface area because newly generated pores in attapulgite will be plugged by impurities [12]. Ma used a l mol/L NaCl solution to exchange Ca 2+ and Mg 2+ cations in attapulgite, improving efficiency of exchanging surfactant for cation in attapulgite before modifying attapulgite by organic means [13].…”

mentioning

confidence: 99%

Optimized Preparation of Directional Modified Attapulgite and its Application to Adsorbance of Humic Acid in Polluted Raw Water Effluent

Zou¹,

Wang²,

Ling³

2016

JRST

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Natural attapulgite modified using acid activation, heat treatment, and organic modification was investigated as a humic acid adsorbent and an optimal modification method was confirmed. Results suggest that acid activation should be performed first and followed by organic modification. Optimum dosage of modified attapulgite was 0.7 g/L and the humic acid removal rate reached 97%. Optimum modification conditions were as follows: acid concentration at 3 mol/L, sodium chloride concentration at 0.5 mol/L, sodium treatment duration was 2 h, modifier amount was 3%, and microwave modification time was 9 min. Modified attapulgite prepared as such may be beneficial for water treatment processes.

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Acid activation of a palygorskite with HCl: Development of physico-chemical, textural and surface properties

Cited by 192 publications

References 17 publications

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

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

Effects of acid treatment on the clay palygorskite: XRD, surface area, morphological and chemical composition

Optimized Preparation of Directional Modified Attapulgite and its Application to Adsorbance of Humic Acid in Polluted Raw Water Effluent

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