Studies on toluidine blue reaction with sulfite in aqueous solution and role of Cu(II) as promoter

Jonnalagadda, Sreekantha B.; Gollapalli, Nageswara Rao

doi:10.1002/(sici)1097-4601(1999)31:8<539::aid-kin3>3.0.co;2-u

Cited by 9 publications

(3 citation statements)

References 27 publications

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“…Also, for SBA‐15 silica a significant increase in TBO adsorption is observed at a pH value of 6. This is due to at pH values higher than 6, the TBO is clearly positively charged (pK a = 7.2) favoring the electrostatic interaction between dye and adsorbent . On the other hand, the slightly decrease in dye adsorption for MCF at high pH could be attributed to the competition between OH − ions and negatively charged mesoporous silica .…”

Section: Resultsmentioning

confidence: 96%

Adsorption performance of mesoporous silicas towards a cationic dye. Influence of mesostructure on adsorption capacity

Meléndez‐Ortiz

Puente-Urbina²,

Mercado-Silva³

et al. 2019

Int J Applied Ceramic Tech

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The dye adsorption performance of four mesoporous silicas with different structure and textural properties, MCM-41, MCM-48, SBA-15 and mesocellular silica foam (MCF), was studied and compared by using toluidine blue O (TBO) as dye model in aqueous solution. These materials were characterized by X-ray diffraction (XRD), small-angle X-ray scattering, nitrogen adsorption-desorption analyses, and transmission electron microscopy (TEM). The effect of some parameters such as adsorbent dosage, contact time, temperature, and pH on the TBO removal in aqueous solution was studied. Results showed that adsorption capacity raised when adsorbent dosage, contact time and pH solution were increased while an increase in temperature decreased the adsorption of TBO. Langmuir, Freundlich and Temkin isotherm models were employed to elucidate the adsorption mechanism while the adsorption rate data were analyzed according to the pseudo-first and second-order kinetic models. Results showed that adsorption of TBO onto MCM-48, SBA-15, and MCF fitted well the Freundlich isotherm model while the kinetic studies showed that adsorption process could be better described by the pseudo-second-order model for all mesoporous silicas. Finally, some solvents were evaluated to carried out dye desorption from the TBO-loaded mesoporous silicas founding that acetic acid was the most efficient. K E Y W O R D Sadsorbent, dye adsorption: MCM-41, mesocellular silica foam, mesoporous silica

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Section: Resultsmentioning

confidence: 96%

Adsorption performance of mesoporous silicas towards a cationic dye. Influence of mesostructure on adsorption capacity

Meléndez‐Ortiz

Puente-Urbina²,

Mercado-Silva³

et al. 2019

Int J Applied Ceramic Tech

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“…Moreover, the proposed mechanism is clearly supported by a kinetic study based on the reaction of TB + with sulte at pH 7.2, in which Cu 2+ ions play an active role as a promoter or catalytic activator. 35 In the relevant kinetic study, it was also observed that Cu-TB, Cu-sulte and Cu-TB-sulte species based on binary and ternary interactions have complex formation constants of 7.168, 6.367 and 14.291 with a standard deviation ranging from 0.003 to 0.008 at pH 7.2. Thus, for further studies, the different analytical variables affecting CPE efficiency were optimized in order to achieve the maximum sensitivity.…”

Section: Resultsmentioning

confidence: 99%

A new simple UV-Vis spectrophotometric method for determination of sulfite species in vegetables and dried fruits using a preconcentration process

Altunay

Gürkan

2016

Anal. Methods

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“…Also, the reduction of TB + or TBH 2+ by ascorbic acid at 600 nm was used for the kinetic determination of ascorbic acid in fruits and vegetables in linear ranges of 3-35 and 5-50 mg L −1 by slope or fixed-time and variable time methods, respectively [48]. Similarly, it is seen that Cu 2+ ion as soft metal ion selectively enhances the rate of reaction between TB + (or TBH 2+ ) and SO 3 2− at 633 nm by forming a ternary complex with a stability constant of logK f : 14.291 with standard deviation of 0.007 at pH 7.2 [49].…”

Section: Resultsmentioning

confidence: 99%

Extraction, preconcentration and spectrophotometric determination of trace levels of thiosulfate in environmental waters

Gürkan

Altunay

Gürkan³

2017

J IRAN CHEM SOC

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are statistically in a good agreement with those obtained by DTNB method. Finally, the method developed was successfully applied to the preconcentration and determination of trace thiosulfate from environmental waters. Abstract In the existing study, a new vortex-assisted cloud point extraction (VA-CPE) method was developed for determination of low levels of thiosulfate in environmental waters at 632 nm by spectrophotometry. The method is selectively based on charge-transfer-sensitive ion-pair complex formation of Ag(S 2 O 3 ) 2 3− , which is produced by the reaction of thiosulfate with excess Ag + ions with toluidine blue (3-amino-7-dimethylamino-2-methylphenazathionium chloride, TB + ) and then its extraction into micellar phase of polyethylene glycol 4-tert-octylphenyl ether (Triton X-45) in presence of Na 2 SO 4 as salting-out agent at pH 7.0. All the factors affecting complex formation and VA-CPE efficiency were optimized in detail. Under the optimized conditions, the linear calibration curves for thiosulfate were in the range of 0.2-120 and 5-180 µg L −1 with sensitivity improvement of 81-folds and 15-folds, respectively, as a result of efficient mass transfer obtained by CPE with and without vortex, while it changed in the range of 260-3600 µg L −1 without preconcentration at 642 nm. The limits of detection and quantification of the method for VA-CPE were found to be 0.05 and 0.22 µg L −1 , respectively. The precision (expressed as the percent relative standard deviation) was in range of 2.5-4.8% (5, 10 and 25 µg L −1 , n: 5). The method accuracy was validated by comparing the results to those of an independent 5,5′-dithiobis(2-aminobenzoic acid) (DTNB) method as well as recovery studies from spiked samples. It has been observed that the results * Ramazan Gürkan Keywords

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Studies on toluidine blue reaction with sulfite in aqueous solution and role of Cu(II) as promoter

Cited by 9 publications

References 27 publications

Adsorption performance of mesoporous silicas towards a cationic dye. Influence of mesostructure on adsorption capacity

Adsorption performance of mesoporous silicas towards a cationic dye. Influence of mesostructure on adsorption capacity

A new simple UV-Vis spectrophotometric method for determination of sulfite species in vegetables and dried fruits using a preconcentration process

Extraction, preconcentration and spectrophotometric determination of trace levels of thiosulfate in environmental waters

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