Preparation and characterization of terbium palygorskite clay as acid catalyst

Melo, D. M. A.; Ruiz, Juan Alberto Chávez; Melo, M. A. F.; Sobrinho, Eledir V.; Schmall, Morton.

doi:10.1016/s1387-1811(00)00155-4

Cited by 52 publications

(27 citation statements)

References 8 publications

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“…[6][7][8][9][10] However, the microstructural properties of activated clays both determine and limit their potential applications. [11][12][13] Thus it is necessary to take into account the mineralogical composition of clay deposits in order to apply acid leaching at an appropriate acid/clay ratio for the preparation of clay products that retain a layered morphology. [14][15][16] The most important parameter that determines the catalytic power and adsorption capacity of clay-based materials is the amount of accessible surface area.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Unye bentonite after treatment with sulfuric acid

Çağlar¹,

Afsin²,

Koksal³

et al. 2013

Quím. Nova

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Recebido em 4/9/12; aceito em 25/3/13; publicado na web em 13/6/13Unye bentonite was found to consist predominantly of a dioctahedral smectite along with quartz, tridymite, cristobalite, and minor fractions of feldspar and anatase. A considerable amount of Al was retained as a constituent in acid-resistant impurities following the decomposition of the montmorillonite via acid treatment at an acid/clay ratio of 0.4. These impurities were mesoporous with a maximum surface area of 303.9±0.4 m 2 g -1 . A sharp decrease in the d 001 lattice spacing of the montmorillonite to 15.33 Å reflected the reduction of the crystallinity in the activated products. In addition, the increase in the ease with which newly formed hydroxyl groups were lost paralleled the severity of the acid treatment.

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Section: Introductionmentioning

confidence: 99%

Characterization of Unye bentonite after treatment with sulfuric acid

Çağlar¹,

Afsin²,

Koksal³

et al. 2013

Quím. Nova

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“…[3]. Entretanto, seu uso na adsorção depende de diversos fatores, tais como pH, tipo e concentração do metal adsorvido, tempo de adsorção, além das características da argila a ser usada [4].…”

Section: Introductionunclassified

Caracterização e usos de argilas bentonitas e vermiculitas para adsorção de cobre (II) em solução

2002

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ResumoVários trabalhos tratam da remoção de metais por argilas e argilominerais. O processo de remoção geralmente ocorre por precipitação, troca iônica e adsorção. Neste trabalho estudou-se a adsorção de solução de Cu (II) em vermiculita, bentonitas sódica e cálcica, proveniente de Campina Grande-PB , tendo-se como variáveis pH, tempo de contato e concentração do adsorvente. Os ensaios foram realizados à temperatura ambiente e as medidas de Absorção Atômica foram feitas no sobrenadante e no resíduo sólido. As argilas bentonitas cálcicas, provenientes de Campina-Grande (PB), sódica de Wyoming (Wyoming-USA) e sódicas (preparadas em laboratório) e as vermiculitas (provenientes do Piauí) foram caracterizadas antes e após o processo de adsorção de Cu (II) em solução através das técnicas, análise química, TG e DTA, área superficial (BET), espectroscopia na região de infravermelho, difração de raios X e medidas de pH. Os resultados mostram que as argilas estudadas adsorvem metais pesados através da troca iônica e que a vermiculita foi mais eficaz no processo, adsorvendo 40,9% de cobre da solução em estudo, em relação às outras argilas envolvidas no processo. Palavras-chave: vermiculita, argilas, adsorção, cobre (II). Abstract Mineral clays have been extensively used for metal removal. The process involves precipitation, ion exchange and adsorption. The present investigation assessed the adsorption of Cu (II) solution by natural vermiculite and both natural

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“…[23][24][25] In the spectra of poly(AMPS-DMAPMA) gel samples, a very broad band around 3330 cm À1 was observed due to the OH of the moisture absorbed by the hydrogel. This strong broad band overlaps the secondary amide NAH stretching band.…”

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confidence: 99%

Nanocomposite super‐swelling hydrogels with nanorod bentonite

Darvishi

Kabiri

Zohuriaan‐Mehr

et al. 2011

J of Applied Polymer Sci

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A modified bentonite (nanorod bentonite) was obtained from conventional bentonite by an ultrasonic treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicated that modified bentonite comprised rod-shape morphology without any change in the chemical structure confirmed by Fourier transform infrared (FTIR) spectroscopy and Xray diffraction (XRD) patterns. Novel super-swelling hydrogels with nanocomposite structure were then prepared via solution polymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and (N-[3-(dimethylamino)propyl] methacrylamide) (DMAPMA) in the presence of the nanobentonite and a crosslinker. The DMAPMA consisted of either intercalant or monomer in the polymerization. The hydrogel products were characterized by FTIR, swelling studies, dynamic mechanical thermal analysis (DMTA), XRD, and rheological measurements. It was proposed that exfoliated and intercalated morphology were obtained at low and high-nanobentonite contents, respectively. DMTA indicated that mechanical properties of the dried gel were improved with raising the clay content. In the water-swollen state, storage modulus was considerably increased in nanocomposites having <8% of modified bentonite, and then it was decreased at the higher clay content due to interfering effect of the clay in polymerization progression.

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Preparation and characterization of terbium palygorskite clay as acid catalyst

Cited by 52 publications

References 8 publications

Characterization of Unye bentonite after treatment with sulfuric acid

Characterization of Unye bentonite after treatment with sulfuric acid

Caracterização e usos de argilas bentonitas e vermiculitas para adsorção de cobre (II) em solução

Nanocomposite super‐swelling hydrogels with nanorod bentonite

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