Adsorption of Monovalent Organic Cations on Sepiolite: Experimental Results and Model Calculations

Rytwo, Giora; Nir, Shlomo; Margulies, L.; Casal, Blanca; Merino, Jesús; Ruiz‐Hitzky, Eduardo; Serratosa, José M.

doi:10.1346/ccmn.1998.0460313

Cited by 126 publications

(42 citation statements)

References 24 publications

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“…The same value of the binding coefficient, K, which describes the formation of complexes of two CV molecules, can be applied to both clays, and in fact, also for adsorption in sepiolite (Rytwo et al, 1998). In illite and montmorillonite, the binding coefficients, K, for the formation of neutral complexes by the organic monovalent cations are significantly larger than those for inorganic cations and the same sequence applies to K values for monovalent cations CV >> BTMA > BTEA > Cs > K > Na > Li.…”

Section: Discussionmentioning

confidence: 99%

Modeling of Organic and Inorganic Cation Sorption by Illite

Polubesova

Nir

1999

Clays and clay miner.

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Abstraet--Sorption of several organic and inorganic cations on illite (Clay Minerals Society Source Clay Imt-2) was determined experimentally and results compared to model calculations. The cations studied were crystal violet (CV+), benzyltrimethylammonium (BTMA § benzyltriethylammonium (BTEA+), Ca 2+, Mg 2+, K +, Na +, Cs +, and Li +. The adsorption-model calculations involved a solution of the electrostatic Gouy-Chapman equations. The model considered specific adsorption and sorption/exclusion in the double-layer region in a closed system. Model calculations considered the simultaneous presence of four to six cations in the system. The adsorption of CV included formation of neutral and charged complexes. The adsorption attained 0.37 mol kg i or 150% of the cation exchange capacity (CEC) of illite in aqueous suspension. The adsorption of BTMA and BTEA did not exceed the CEC and was reduced with an increase in ionic strength. The sorption of CV below the CEC was rather insensitive to the ionic strength because of the large binding coefficients and was only slightly reduced in NaC1, CsC1, or Na2SO4 solutions. When added in amounts exceeding the CEC in high ionic strength, 0.667 M NaNO 3, NaC1, or CsC1 solutions, the adsorbed quantities of CV increased to three times the CEC. At high sulphate concentrations (0.333 M Na2SO4), the adsorption was below the CEC. Model calculations yielded satisfactory simulations for the adsorption, particularly for cations added in amounts approaching or exceeding the CEC. The binding coefficients for formation of neutral complexes followed the sequence: CV > Ca > BTMA > BTEA > Cs > Mg > K > Na > Li. Model calculations also suggested that sites were present which bound exchangeable cations, particularly K +, Na +, and Mg 2+, very tightly.

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Section: Discussionmentioning

confidence: 99%

Modeling of Organic and Inorganic Cation Sorption by Illite

Polubesova

Nir

1999

Clays and clay miner.

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“…Seu formato acilar (como agulhas) pode gerar maior molhabilidade em polímeros apolares, além de uma maior área superficial. A modificação de argila com os silanos pode, ainda, agir promovendo maior adesão entre as fases [14,15] . Espera-se que as membranas poliméricas obtidas apresentem propriedades mecânicas e térmicas superiores às das membranas fluoradas comerciais disponíveis para a construção de PEMFC's.…”

Section: -Membranas Híbridas Com Potencial Uso Em Células a Combustívunclassified

Membranas Híbridas com Potencial Uso em Células a Combustível - Parte 2: Nanocompósitos de Poli(Carbonato) Sulfonado

Gomes¹,

Machado²,

Filho³

et al. 2014

Polímeros

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Resumo: Membranas poliméricas condutoras de íons têm sido cada vez mais estudadas para o uso em células a combustível. Entretanto, as membranas poliméricas disponíveis no mercado para este fim apresentam algumas limitações de condições de trabalho. Neste estudo o poli(carbonato) modificado quimicamente para uso como membrana condutora de íons foi caracterizado e teve seu desempenho avaliado. A formação de um nanocompósito baseado em sepiolita visou ao aumento na resistência mecânica e térmica das membranas, propriedades, a princípio, prejudicadas pela sulfonação do material. As membranas foram avaliadas por FTIR, DSC, TGA, DMA, inchamento em água, transmissão de vapor de água e resistência à migração iônica. Os resultados mostraram ser possível atingir um balanço estrutura versus propriedades visando a um elevado desempenho das membranas. Palavras-chave: Membrana polimérica, nanocompósito polimérico, célula a combustível, eletrólito polimérico. Hybrid Membranes of Polymer/Clay for Fuel Cell Applications. Part 2. Sulphonated Poly(Carbonate) NanocompositesAbstract: Ion-conducting polymeric membranes have been studied for use in fuel cells. However, polymeric membranes available in the market show some disadvantages. Here we modified polycarbonate chemically for use as ion-conducting membranes, and investigated its performance. The use of the nanoclay sepiolite aimed at improving the mechanical and thermal resistance, which are negatively affected by polymer sulphonation. The membranes were evaluated using FTIR, DSC, TGA, DMA, water swelling, water vapor uptake and ionic migration resistance. The results indicated it to be possible to reach a tradeoff between structure and properties for obtaining high-performance membranes.

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“…Factorial designs are widely used to investigate the effects of experimental factors and the interactions between those factors in a response. The advantages of factorial experiments include relatively low cost, a reduced number of experiments, and increased possibilities to evaluate interactions among the variables (Rytwo, et al, 1998;Im, et al, 2012).…”

Section: Adsorption Proceduresmentioning

confidence: 99%

Optimization study of adsorption of crystal violet and congo red onto sepiolite and clinoptiolite

2017

Global NEST Journal

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The purpose of this study was to investigate the adsorption properties of locally available sepiolite and clinoptilolite materials as adsorbents for the removal of crystal violet and congo red dye ions from aqueous solution. Previous experiments have revealed that two variables, concentration and adsorbent dosage, have a significant effect on removal efficiency. In order to find the set of operating conditions for these variables that result in the best removal efficiency, central composite design of experiments was utilized. The results showed that sepiolite is a suitable material with 99% removal efficiency for the adsorption of both crystal violet and congo red from aqueous solution. However, in spite of clinoptilolite is also a suitable adsorbent for crystal violet, removal efficiency of congo red is rather low.

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Adsorption of Monovalent Organic Cations on Sepiolite: Experimental Results and Model Calculations

Cited by 126 publications

References 24 publications

Modeling of Organic and Inorganic Cation Sorption by Illite

Modeling of Organic and Inorganic Cation Sorption by Illite

Membranas Híbridas com Potencial Uso em Células a Combustível - Parte 2: Nanocompósitos de Poli(Carbonato) Sulfonado

Optimization study of adsorption of crystal violet and congo red onto sepiolite and clinoptiolite

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