• Journal of the Korean Society of Industry Convergence
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• v.14 no.1
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• pp.23-27
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• 2011

In this study, the experiments for surface enhancement of silver mirror substrates were done, where we checked the characteristics of silver mirror substrate made by Tollen's method. The surface enhancement of Eriochrome Black T(EBT) was analyzed by silver mirror substrates. We observed the SERS spectra of EBT. The assignments of the vibrational bands shown in SERS spectra are given based on both literature and the semi-empirical calculations at the PM3 methods. Finally, we deduced that the adsorption orientation of EBT was little tilted perpendicular to the silver mirror surfaces by using of the surface selection rules.

• Analytical Science and Technology
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• v.11 no.4
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• pp.305-310
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• 1998

A reactive dye synthesized with an amine containing Eriochrome Black T derivative and cynauric chloride was immobilized on a cellulose membrane to construct an optical sensor for the detection of divalent transition metal ions in aqueous solution. The response of this reactive dye-based optical sensor was as sensitive as that of Eriochrome Black T in solution phase. Its typical detection limits for $Zn^{2+}$ and $Co^{2+}$ were $6.3{\times}10^{-5}mol/l$ and $2.5{\times}10^{-4}mol/l$, respectively. No loss in the sensitivity of reactive dye-based sensor was observed even the pH of flowing solutions continually varied for an extended period of time.

• Journal of Environmental Science International
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• v.25 no.12
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• pp.1717-1726
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• 2016

In this study, the reductive decolorization of three acid and basic dyes using modified zero-valent iron (i.e., acid-washed iron (Aw/Fe) and palladium coated iron (Pd/Fe)) at various pH conditions (pH 3~5) was experimentally investigated and the decolorization characteristics were evaluated by analyzing the absorbance spectra and reaction kinetics. In the case of acid dyes such as methyl orange and eriochrome black T, color removal efficiencies increased as initial pH of the dye solution decreased. However, the color removal of methylene blue, a basic dye, was not affected much by the initial pH and more than 70% of color was removed within 10 min. During the decolorization reaction, the absorbance of methyl orange (${\lambda}_{max}=464nm$) and eriochrome black T (${\lambda}_{max}=528nm$) decreased in the visible range but increased in the UV range. The absorbance of methylene blue (${\lambda}_{max}=664nm$) also decreased gradually in the visible range. Pseudo-zero order, pseudo-first order, and pseudo-second order kinetic models were used to analyze the reaction kinetics. The pseudo-second order kinetic model was found to be the best with good correlation. The decolorization reaction rate constants ($k_2$) of methylene blue were relatively higher than those of methyl orange and eriochrome black T. The reaction rate constants of methyl orange and eriochrome black T increased with a decrease in the initial pH.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.167-175
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• 2022

The degradation of EBT (Eriochrome Black T) in an aqueous solution was investigated at various values of pH, Ferrate (VI) dosage, initial concentration, aqueous solution temperature. The maximum degradation efficiency was 95.42% at pH 7 and in that experimental condition, the kapp value was 872.87 M-1s-1. The degradation efficiency was proportional to the dosage of Ferrate (VI). Also, the initial rate constant of EBT degradation increased with decreasing of the EBT initial concentration. In addition, the degradation rate of EBT was increased from 74.04% to 95.42% when the temperature in the aqueous solution was increased from 10℃ to 45℃. The activation energy value was 11.9 kJ/mol for EBT degradation. Overall, the results of the degradation experiment showed that Ferrate (VI) could effectively oxidize the EBT in the aqueous phase.

• Journal of the Korean Chemical Society
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• v.17 no.4
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• pp.256-261
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• 1973

Complex formation of magnesium-Eriochrome Black T at constant ionic strength and hydrogen ion concentration have been studied spectrophotometrically in acetonitrile solution. The measured pH values were calibrated with standard buffer solutions by using a glass electrode Ag/0.1M $AgNO_3$ reference electrode couple. The results are as follows;$E_{glass}=716+59.1\;logA_{H+}[mv]$+(in mv. vs. Ag reference electrode for picric acid $-10^{-3}M$ tetramethylammonium picrate buffer), and $E_{glass}=1,193+59.1\;logA_{H+}[mv]$(in mv. vs. Ag reference electrode for 1,3-diphenylguanidine $-3{\times}10^{-3}M $ 1,3-diphenylguanidine perchlorate buffer). The acid dissociation exponent of ligand, $ pK_{H,EBT-}$was found to be 9.1. The conditional formation constants of $MgEBT^{-}$complex by log-ratio method were 3.97 (when m = 2) and 5.02 (when m = 1) as $log K_n$, respectively, for the reaction of $H_mEBT^{(3-m)-} + Mg^{2+} {\leftrightarrow}MgEBT^{-} + mH^{+}$. The present study showed that$MgEBT^{-}$ has the composition of 1:1 which agrees with the result of Schwarzenbach et al. in aqueous solution.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.259-277
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• 2017

Adsorption is a widely used technique for the removal of dyes from wastewaters by variety of adsorbents. In this work, the main focus is on the potential assessment of anion exchange membrane for the removal of different dyes using batch system and investigation of experimental data by applying various kinetic and thermodynamic models. The removal of anionic dyes i.e., Eosin-B, Eriochrome Black-T and Congo Red by anion exchange membrane BII from aqueous solution was carried out and effect of various parameters such as contact time, membrane dosage, temperature and ionic strength on the percentage removal of anionic dyes was studied. The experimental data was assessed by kinetic models namely pseudo-first-order, pseudo-second-order, Elovich liquid film diffusion, Bangham and the modified Freundlich models equation have been used to analyze the experimental data. These results indicate that the adsorption of these anionic dyes on BII follows pseudo-second-order kinetics with maximum values of regression coefficient (0.992-0.998) for all the systems. The adsorption of dyes was more suitable to be controlled by a liquid film diffusion mechanism. The adsorptive removal of dye Eosin-B and Eriochrome Black-T were decreased with temperature and thermodynamic parameters such as free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$) and entropy (${\Delta}S^o$) for adsorption of dyes on membrane BII were calculated at 298 K, 308 K and 318 K. The values of enthalpy and entropy were negative for EB and EBT representing that the adsorption of these dyes on BII is physiosorptive and exothermic in nature. Whereas the positive values of enthalpy and entropy for CR adsorption on BII, indicating that its adsorption is endothermic and spontaneous in nature. It is evident from this study that anion exchange membrane has shown good potential for the removal of dyes from aqueous solution and it can be used as adsorbent for dues removal on commercial levels.

• Applied Biological Chemistry
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• v.10
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• pp.1-13
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• 1968

Phytin is a salt(mainly calcium and magnesium) of phytic acid and its purity and molecular formula can be determined by assaying the contents of phosporus, calcium and magnesium in phytin. In order to devise a new method for the quantitative analysis of the three elements in phytin, the chelatometric method was developed as follows: 1) As the pretreatment for phytin analysis, it was ashfied st $550{\sim}600^{\circ}C$ in the presence of concentrated nitric acid. This dry process is more accurate than the wet process. 2) Phosphorus, calcium and megnesium were analyzed by the conventional and the new method described here, for the phytin sample decomposed by the dry process. The ashfied phytin solution in hydrochloric acid was partitioned into cation and anion fractions by means of a ration exchange resin. A portion of the ration fraction was adjusted to pH 7.0, followed by readjustment to pH 10 and titrated with standard EDTA solution using the BT [Eriochrome black T] indicator to obtain the combined value of calcium and magnesium. Another portion of the ration fraction was made to pH 7.0, and a small volume of standard EDTA solution was added to it. pH was adjusted to $12{\sim}13$ with 8 N KOH and it was titrate by a standard EDTA solution in the presence of N-N[2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphytate)-3-naphthoic acid] diluted powder indicator in order to obtain the calcium content. Magnesium content was calculated from the difference between the two values. From the anion fraction the magnesium ammonium phosphate precipitate was obtained. The precipitate was dissolved in hydrochloric acid, and a standard EDTA solution was added to it. The solution was adjusted to pH 7.0 and then readjusted to pH 10.0 by a buffer solution and titrated with a standard magnesium sulfate solution in the presence of BT indicator to obtain the phosphorus content. The analytical data for phosphorus, calcium and magnesium were 98.9%, 97.1% and 99.1% respectively, in reference to the theoretical values for the formula $C_6H_6O_{24}P_6Mg_4CaNa_2{\cdot}5H_2O$. Statical analysis indicated a good coincidence of the theoretical and experimental values. On the other hand, the observed values for the three elements by the conventional method were 92.4%, 86.8% and 93.8%, respectively, revealing a remarkable difference from the theoretical. 3) When sodium phytate was admixed with starch and subjected to the analysis of phosphorus, calcium and magnesium by the chelatometric method, their recovery was almost 100% 4) In order to confirm the accuracy of this method, phytic acid was reacted with calcium chloride and magnesium chloride in the molar ratio of phytic: calcium chloride: magnesium chloride=1 : 5 : 20 to obtain sodium phytate containing one calcium atom and four magnesium atoms per molecule of sodium phytate. The analytical data for phosporus, calcium and magnesium were coincident with those as determine d by the aforementioned method. The new method employing the dry process, ion exchange resin and chelatometric assay of phosphorus, calcium and magnesium is considered accurate and rapid for the determination of phytin.