Interactions of Some Large Organic Cations with Bentonite in Dilute Aqueous Systems

Narine, Deoraj R.; Guy, Robert D.

doi:10.1346/ccmn.1981.0290306

Cited by 62 publications

(41 citation statements)

References 18 publications

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“…46 In the present study, ionic strength of the solution exhibited some effect on adsorption of montmorillonite. The amount of MB adsorbed onto montmorillonite was decreased with increasing concentration of NaCl in solution ( Figure 6).…”

Section: 45mentioning

confidence: 51%

Cationic Dye (Methylene Blue) Removal from Aqueous Solution by Montmorillonite

Fìl¹,

Özmetin²,

Korkmaz³

2012

Bulletin of the Korean Chemical Society

113

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Color impurity in industrial effluents pose a significant risk to human health and the environment, so much effort has been expended to degrade them using various methods, including the use of clay minerals as adsorbent. The purpose of this study was to advance understanding of the mechanisms for the removal of methylene blue (MB) from aqueous solutions onto montmorillonite as an adsorbent. Preliminary experiments showed that montmorillonite was effective for this purpose and adsorption equilibrium could be reached in about 24 h. Adsorption capacity of the clay decreased with increase in temperature and ionic strength, and increased with in pH. The fitness of equilibrium data to common isotherm equations such as the Langmuir, Freundlich, Elovich, Temkin and Dubinin-Radushkevich were tested. The Langmuir equation fitted to equilibrium data better than all tested isotherm models. Thermodynamic activation parameters such as ΔG 0 , ΔS 0 and ΔH 0 were also calculated and results were evaluated. As result montmorillonite clay was found as effective low cost adsorbent for removal of cationic dyes from waste waters.

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Section: 45mentioning

confidence: 51%

Cationic Dye (Methylene Blue) Removal from Aqueous Solution by Montmorillonite

Fìl¹,

Özmetin²,

Korkmaz³

2012

Bulletin of the Korean Chemical Society

113

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“…The extended model is applied to the adsorption of two monovalent cationic organic dyes to the surface of montmorillonite, namely methylene blue (MB) (Pham Thi Hang and Brindley, 1970;Narine and Guy, 1981) and thioflavin T (TFT), which has been found to be effective in photostabilizing an insecticidal nitromethylene heterocycle on the surface of montmorillonite . The relative strengths of interactions between these organic cations and the clay are also compared with those of sodium and cesium.…”

Section: Copyright 9 1988 the Clay Minerals Societymentioning

confidence: 99%

“…Several studies have focused on the adsorption of cationic organic dyes to negatively charged smectites (Chu and Johnson, 1979;De et al, 1974;Ghosal and Mukherjee, 1972;Grauer et al, 1984;Pham Thi Hang and Brindley, 1970;Narine and Guy, 1981;Venugopal and Nair, 1974), Margulies et al (1985 suggested a method of photostabilization of pesticides which is based on coadsorbing on a clay surface the photolabile pesticide and an adequate organic cation that acts as energy acceptor. In such a system the organic cation must be strongly attached to the surface of the clay in order to prevent contamination of soil and water.…”

Section: Introductionmentioning

confidence: 99%

“…In such a system the organic cation must be strongly attached to the surface of the clay in order to prevent contamination of soil and water. Although it is well documented that organic cations adsorb to the clay surface significantly more strongly than inorganic cations, and that adsorption can proceed beyond the cation-exchange capacity (CEC) of the clay (De et al, 1974;Narine and Guy, 1981), no theoretical model has been suggested to evaluate the strengths of these interactions. Non-coulombic forces obviously play an important role in the adsorption of these usually large molecules.…”

Section: Introductionmentioning

confidence: 99%

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Model for Competitive Adsorption of Organic Cations on Clays

Margulies

1988

Clays and clay miner.

126

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Abstract--The adsorption on montmorillonite of two monovalent organic cations, methylene blue (MB) and thioflavin T (TFT), was studied in four different situations: (1) separate adsorption of MB or TFT; (2) competitive adsorption of TFT and Cs; (3) competitive adsorption of the two organic cations from their equimolar solutions; and (4) adsorption of TFT on a clay whose cation-exchange capacity (CEC) had been previously saturated with MB. MB and TFF adsorbed to as much as 120% and 140% of the CEC, respectively. Cs did not appear to compete with TFT for the adsorption sites of the clay. TFT molecules adsorbed more strongly than those of MB and displaced them from the clay surface. A model was developed to evaluate the strength of the clay-organic cation interactions. The specific binding of the cations to the negatively charged surface, determined by solving the electrostatic equations, appears to account for adsorption exceeding the CEC and formation of positively charged complexes, which are due to non-coulombic interactions between the organic ligands.The charge reversal predicted by the model beyond the CEC of the clay was confirmed by microelectrophoretic experiments. Particles in a sample of montmorillonite loaded with 50 meq TFT/100 g clay moved to the positive electrode, whereas in samples containing the two dyes, MB and TFT, coadsorbed at a total concentration of 100-120 meq/100 g clay, the particles moved to the negative electrode. Binding coefficients describing the formation of neutral and charged complexes of TFT and the clay were larger than those for MB and the clay, thereby explaining the preferential adsorption of TFT observed experimentally. The binding coefficients for the formation of neutral complexes of either MB and TFT and the clay were more than six orders of magnitude larger than those previously reported for inorganic monovalent cations.

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“…It has not been shown that the binding affinities to montmorillonite of other inorganic cations such as NH4 + or Ba 2+ are extremely large. On the other hand, organic cations have been found to adsorb strongly to clays (Chu and Johnson, 1979;De et al, 1974;Ghosal and Mukherjee, 1972;Grauer et al, 1984;Lagaly, 1984;Mortland, 1970;Narine and Guy, 1981;Raussel-Colom and Serratosa, 1987;Theng, 1974;Venugopal and Nair, 1974). The organic cations methylene blue (MB) and thioflavin T (TFT) were previously shown to have binding coefficients of at least l0 s and 109 M -1 (Margulies et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Use of Methylene Blue and Crystal Violet for Determination of Exchangeable Cations in Montmorillonite

Rytwo

1991

Clays and clay miner.

117

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Ahstract--A procedure for the determination of cation exchange capacity (CEC) and the amounts of exchangeable cations adsorbed to montmorillonite is proposed. The method consists of a single incubation of the clay in a suspension containing a low concentration of an organic dye of large binding affinity, followed by analysis of the displaced inorganic cations by inductively-coupled plasma emission spectrometry (ICPES). The CEC is obtained by taking the largest sum of displaced exchangeable cations. Montmorillonite suspensions were incubated with methylene blue (MB) or crystal violet (CV) at dye concentrations below 4 mM, for one, three or fourteen days. For total dye concentrations up to the CEC, all the dye was adsorbed and equivalent amounts of exchangeable cations were released. Both dyes could adsorb to the clay in excess of the CEC.After one day of incubation in the presence of dye concentrations of about 50% in excess of the CEC, the total amounts of cations released were reduced to below the CEC. This reduction was interpreted as due to massive aggregation of the clay particles induced by the dye. With CV the total amounts of cations released after three or fourteen days of incubation increased and became equal to the CEC.The same CEC was found for Na-, Ca-and SWyl crude-montmorillonite, by employing either of the dyes.

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Interactions of Some Large Organic Cations with Bentonite in Dilute Aqueous Systems

Cited by 62 publications

References 18 publications

Cationic Dye (Methylene Blue) Removal from Aqueous Solution by Montmorillonite

Cationic Dye (Methylene Blue) Removal from Aqueous Solution by Montmorillonite

Model for Competitive Adsorption of Organic Cations on Clays

Use of Methylene Blue and Crystal Violet for Determination of Exchangeable Cations in Montmorillonite

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