Caracterizações de argilas bentoníticas e síntese de argilas organofílicas para uso em nanocompósitos poliméricos: parte II

Barbosa, Renata; Morais, Dayanne Diniz Souza; Araújo, Edcleide Maria; Mélo, Tomás Jefférson Alves de

doi:10.1590/s0366-69132012000300013

Cited by 6 publications

(5 citation statements)

References 17 publications

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“…In Table II, cation exchange capacity (CEC) values for the natural and centrifuged clay samples are presented, as determined by the methylene blue method. The natural samples had CEC values ranging from 40 to 72 meq/100 g of dry clay, values typically found for bentonite clay from Paraíba, Brazil, using the methylene blue method, consistent with data found in [32][33][34][35]. After purification in the centrifuge, the CEC values increased.…”

Section: Resultssupporting

confidence: 83%

Influence of the purification of bentonite clay from new deposits in the state of Paraíba-Brazil for use in water-based drilling fluids

et al. 2018

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Bentonite clay is used all around the world as an additive in drilling fluids. However, impurities present in this material can compromise the compatibility of the clay-fluid system. The present study aimed to analyze the effects of the purification of bentonite samples from new deposits in the state of Paraíba, Brazil, in order to make them usable in water-based drilling fluids. The samples were first purified by centrifugation, and their characteristics were determined using the following techniques: laser granulometry, X-ray diffraction, chemical analysis, cation exchange capacity, thermogravimetric analysis, and differential thermal analysis. After these determinations, the polycationic clay samples were made sodic through the addition of sodium carbonate (Na2CO3) in the proportion of 125 meq/100 g of dry clay. The rheological and filtration properties (apparent viscosity, plastic viscosity, and filtrate volume) were then tested. The results showed that the purification process was efficient for removing accessory minerals such as quartz, iron, and carbonates. With regard to rheological and filtration properties, the results following centrifugation showed that the material can be suitable for use in water-based drilling fluids.

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Section: Resultssupporting

confidence: 83%

Influence of the purification of bentonite clay from new deposits in the state of Paraíba-Brazil for use in water-based drilling fluids

et al. 2018

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“…The AC clay produced a value lower than the range required by the group of smectites (60 cmol/kg), due to the presence of accessory minerals in large quantities. The CEC results of the smectic clay of 88 cmol/kg of dry clay is a typical value for bentonite clays from the State of Paraíba, determined by the methylene blue methodology and compatible with data found in [41,44,50]. According to [51], a CEC so high, of more than 70.0 cmol/kg, indicates the presence of a greater amount of montmorillonite mineral.…”

Section: Materials and Methodologysupporting

confidence: 85%

Characterization of clays from the State of Paraíba, Brazil for aesthetic and medicinal use

Buriti

Silva

et al. 2019

Cerâmica

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This study aimed to evaluate the potential of clays from the State of Paraíba to be used for medicinal, therapeutic and aesthetic treatments. The samples were characterized by X-ray diffraction, X-ray fluorescence chemical composition, thermogravimetry, differential thermal analysis, laser diffraction granulometric analysis, cation exchange capacity, and antimicrobial activity. Based on the study, it was concluded that the clays from the State of Paraíba had properties similar to those of commercial clay. The antimicrobial evaluation revealed that the samples showed no activity against the three bacterial strains of clinical interest: Staphylococcus epidermidis ATCC 12 228, Staphylococcus aureus ATCC 25 923, and Escherichia coli ATCC 25 922. Finally, it was concluded that the clays studied have the potential for technological applications in medicinal, therapeutic, and aesthetic treatments, and as raw material for obtaining biomaterials, due to their stability and biological safety.Este trabalho teve como objetivo avaliar a potencialidade das argilas do estado da Paraíba, visando suas aplicações em tratamentos medicinais, terapêuticos e estéticos. As amostras das argilas foram caracterizadas pelas técnicas de difração de raios X, composição química por fluorescência de raios X, termogravimetria, análise térmica diferencial, análise granulométrica por difração a laser, capacidade de troca catiônica e atividade antimicrobiana. Com base no estudo, concluiu-se que as argilas do estado da Paraíba apresentaram propriedades similares à argila comercial. A avaliação antimicrobiana revelou que as amostras não apresentaram atividade frente a três cepas bacterianas de interesse clínico: Staphylococcus epidermidis ATCC 12 228, Staphylococcus aureus ATCC 25 923 e Escherichia coli ATCC 25 922. Por fim conclui-se que as argilas estudadas possuem potencial tecnológico para aplicações em tratamentos medicinais, terapêuticos, estéticos e como matéria-prima para obtenção de biomateriais, em virtude da sua estabilidade e segurança biológica. Palavras-chave: argilas, biominerais, caracterização, tratamento medicinal.

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“…The exchangeable cation content, expressed in milliequivalents (meq) of the cation per 100 g of clay, is called cation exchange capacity (CEC). The stacking of the structural layers is governed by relatively weak polar and van der Waals forces and, between these layers, there are gaps called galleries or intermediary layers in which the exchangeable cations, such as Na + , Ca 2+ , and Li + , are fixed electrostatically [1,8]. The physicochemical properties of clay minerals are closely associated with surface and surface charge phenomena.…”

Section: Introductionmentioning

confidence: 99%

Influence of the additivation process on cation exchange capacity and viscosity of bentonitic clay dispersions

et al. 2020

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In Brazil, bentonite clays are not naturally sodic and it is an industrial practice the sodium additivation, since sodium ion expands their lamellae allowing a larger amount of water to penetrate. The objective was to analyze the influences of the use of sodium carbonate on the clay during the additivation process, the moisture content and the cure time on cation exchange and viscosity of bentonite clay dispersions for water-based drilling fluids, since there is a shortage of studies on this subject. Newly discovered bentonite clays in Paraíba State, Brazil, were chemically, physically and mineralogically characterized and were additivated with sodium carbonate in aqueous solution (process 1) or in powder form (process 2). Samples with 25% to 60% of moisture (dry basis) were prepared and submitted to cure times of 7 to 45 days. Process 1, as expected, showed better results of cation exchange capacity, viscosity and filtrate volume. The ideal cure time was 15 days. After this period there was a reversal of the cation exchange reactions.

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Caracterizações de argilas bentoníticas e síntese de argilas organofílicas para uso em nanocompósitos poliméricos: parte II

Cited by 6 publications

References 17 publications

Influence of the purification of bentonite clay from new deposits in the state of Paraíba-Brazil for use in water-based drilling fluids

Influence of the purification of bentonite clay from new deposits in the state of Paraíba-Brazil for use in water-based drilling fluids

Characterization of clays from the State of Paraíba, Brazil for aesthetic and medicinal use

Influence of the additivation process on cation exchange capacity and viscosity of bentonitic clay dispersions

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