Metachromasy in clay-dye systems: the adsorption of acridine orange by Na-saponite

Clay Minerals ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 653-663 ◽  
Author(s):  
D. Garfinkel-Shweky ◽  
S. Yariv
Keyword(s):  
Cation Exchange ◽  
Acridine Orange ◽  
Organic Cation ◽  
Interlayer Space ◽  
Aqueous Suspension ◽  
Cationic Dye ◽  
Visible Spectroscopy ◽  
Π Interactions ◽  
Colloidal Properties ◽  
Clay Platelets

AbstractThe adsorption of the cationic dye acridine orange (AO) by Na-saponite and the colloidal properties of the aqueous suspension were investigated by visible spectroscopy and XRD. The organic cation is adsorbed by the mechanism of cation exchange. When small amounts of the dye are adsorbed, the system contains small tactoids and is peptized. At this stage the dye penetrates into the interlayer space and most of it undergoes metaehromasy due to interactions between the aromatic entity and the oxygen plane of the clay. When greater amounts of AO are adsorbed, the clay platelets flocculate to form book-house floes which, with excess AO, are transformed into card-house floes. At this stage metachromasy results from the aggregation of the dye in the interparticle space of the floes, in addition to the π interactions with the oxygen plane. In excess AO, the clay is gradually peptized. At this stage the dispersed clay platelets form small tactoids with monomeric AO in the interlayer space and at the same time adsorb dimerie and polymeric AO cationic species at the solidliquid interface.

Metachromasy in clay dye systems: the adsorption of acridine orange by Na-beidellite

Clay Minerals ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 459-467 ◽  
Author(s):  
D. Garfinkel-Shweky ◽  
S. Yariv
Keyword(s):  
Acridine Orange ◽  
Interlayer Space ◽  
Degree Of Saturation ◽  
Visible Spectroscopy ◽  
Absorption Bands ◽  
Colloidal Properties ◽  
Different Types ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Absorbance Curve

AbstractThe adsorption of the metachromic dye acridine orange (AO) by Na-beidellite was investigated by visible spectroscopy. Different types of clay-AO association were identified from the appearance and location of absorption bands α or β. The colloidal properties were determined from curves of the absorbance vs. the degree of saturation. Three regions were identified in the absorbance curve. In the first region beidellite is peptized with small amounts of AO and the dye penetrates into the interlayer space where it undergoes metachromasy due to π interactions between the aromatic entity and the oxygen plane of the clay. With larger amounts of AO (second region), the clay flocculates due to the aggregation of the dye cations in the interparticle space of the flocs. In excess AO (third region), beidellite is gradually peptized, forming small tactoids with monomeric AO in the interlayer space and at the same time adsorbing dimeric and polymeric AO cationic species at the solid-liquid interface. Compared with the other smectites, AO shows the greatest tendency to undergo metachromasy in the presence of beidellite.

Fabrication of mixed perovskite organic cation thin films via controllable cation exchange

2018 ◽  
Vol 27 (2) ◽  
pp. 024208 ◽  
Author(s):  
Yu-Long Zhao ◽  
Jin-Feng Wang ◽  
Ben-Guang Zhao ◽  
Chen-Chen Jia ◽  
Jun-Peng Mou ◽  
...  
Keyword(s):  
Thin Films ◽  
Cation Exchange ◽  
Organic Cation

Determination of the Cation Exchange Capacity of Clays by Surface Tension Measurements

Clay Minerals ◽  
1993 ◽  
Vol 28 (3) ◽  
pp. 475-481 ◽  
Author(s):  
G. Burrafato ◽  
F. Miano
Keyword(s):  
Surface Tension ◽  
Cation Exchange ◽  
Clay Minerals ◽  
Cation Exchange Capacity ◽  
Mixing Time ◽  
Aqueous Suspension ◽  
Exchange Capacity ◽  
Drilling Fluids ◽  
Accurate Analysis

AbstractThe cation exchange capacity (CEC) of clay minerals has been determined by titration of aqueous suspension of clays with hexadecylpyridinium chloride, monitored using surface tension measurements. In order to make the method suitable for an accurate analysis of the CEC of the clays in drilling fluids or in soils, some parameters affecting the CEC determination (e.g. the presence of carboxymethylcellulose, mixing time and measurement device) have been investigated.

scholarly journals Ethylammonium Lead Iodide Formation in MAPbI3 Precursor Solutions by DMF Decomposition and Organic Cation Exchange Reaction

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 162
Author(s):  
Ryan Taoran Wang ◽  
Elton Enchong Liu ◽  
Alex Fan Xu ◽  
Lory Wenjuan Yang ◽  
Jason Yuanzhe Chen ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Exchange Reaction ◽  
Organic Cation ◽  
Annealing Process ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Lead Iodide ◽  
X Ray ◽  
Cation Exchange Reaction

Extra peaks have constantly been observed in the X-ray diffraction measurement for the CH3NH3PbI3 film. Such mysteries have now been uncovered in this paper, in which powder X-ray diffraction, in situ X-ray diffraction, and scanning electron microscopy measurements were conducted, and these peaks were attributed to the ethylammonium lead iodide (CH3CH2NH3PbI3/EAPbI3). It was found that the formation of EAPbI3 was triggered by the breakdown of N, N-dimethylformamide (DMF), which was adopted as the solvent in the preparation of the precursor solutions. EAPbI3 was generated by the organic cation exchange reaction in the subsequent annealing process. A simple solution for this problem is proposed in this paper as well, which would hopefully help the community to eradicate this impurity.

Removal of cationic dye methyl violet 2B from water by cation exchange membranes

2008 ◽  
Vol 309 (1-2) ◽  
pp. 239-245 ◽  
Author(s):  
Jeng-Shiou Wu ◽  
Chia-Hung Liu ◽  
Khim Hoong Chu ◽  
Shing-Yi Suen
Keyword(s):  
Cation Exchange ◽  
Methyl Violet ◽  
Cationic Dye ◽  
Methyl Violet 2B

The adsorption of berberine by montmorillonite and thermo-XRD analysis of the organo-clay complex

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 223-232 ◽  
Author(s):  
E. Cohen ◽  
T. Joseph ◽  
I. Lapides ◽  
S. Yariv
Keyword(s):  
Thermal Treatment ◽  
Cation Exchange ◽  
Room Temperature ◽  
Interlayer Space ◽  
Divalent Cations ◽  
Xrd Analysis ◽  
Basal Spacing ◽  
Alumino Silicate ◽  
Silicate Layers ◽  
Heating Up

AbstractThe adsorption of the large cationic alkaloid berberine by montmorillonite in aqueous suspensions was investigated. An adsorption isotherm of berberine and desorption isotherms of exchangeable Na+, K+, Mg2+ and Ca2+ were determined by chemical analysis of the non-adsorbed berberine and the released cations in the supernatants. The isotherms suggest that the adsorption of berberine takes place in two different types of reaction mechanism: (1) cation exchange, and (2) a secondary organophyllic adsorption. The cation exchange occurring first is followed by the secondary adsorption which is accompanied by Cl- adsorption. Monovalent cations are exchanged before the divalent cations.Samples loaded with increasing amounts of berberine were examined by X-ray diffraction at room temperature, and after gradual heating up to 420°C. The basal spacing of the loaded samples after the thermal treatment became 1.28 nm, indicating the formation of carbon in the interlayer, thus proving that the adsorbed berberine was located in the interlayer space. At room temperature the basal spacing of samples loaded with 8 and 15 mmol of berberine per 100 g of clay was 1.28–1.30 nm indicating that in the interlayer space berberine cations were lying parallel to the alumino-silicate layers. The basal spacing of a sample with 36 mmol of berberine per 100 g of clay was 1.48 nm. This spacing does not give conclusive information on the arrangement of berberine in the interlayer. The spacing of samples with 57–147 mmol of berberine per 100 g of clay was 1.59 nm, suggesting the presence of bilayers of berberine in the interlayers. During thermal dehydration, the spacing of samples with 36–73 mmol of berberine per 100 g of clay decreased, but that of samples with 105–147 mmol of berberine per 100 g of clay increased to 1.66 nm. These samples contain organophilic adsorbed berberine and it is suggested that due to the thermal treatment berberine was tilted relative to the TOT lamellae, with anhydrous Cl- between the berberine cations.

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