Sorption of Lead by the Selective Ion Exchanger Ostsorb DETA

1992 ◽  
Vol 57 (7) ◽  
pp. 1393-1404 ◽  
Author(s):  
Ladislav Svoboda ◽  
Jan Uhlíř ◽  
Zdeněk Uhlíř
Keyword(s):  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Ion Exchanger ◽  
Preconcentration Procedure ◽  
Bead Cellulose

The properties of Ostsorb DETA, a selective ion exchanger based on modified bead cellulose with chemically bonded diethylenetriamine functional groups, were studied, and its applicability to the preconcentration of trace amounts of lead from aqueous solutions was verified. The conditions of the preconcentration procedure in the column and batch modes were optimized for this purpose. The results obtained were applied to the determination of lead in phosphoric acid.

scholarly journals DETERMINATION OF TYPE OF SOLVATE OF PHOSPHORIC ACID DURING ITS EXTRACTION BY TRIBUTYL PHOSPHATE

2019 ◽  
Vol 62 (5) ◽  
pp. 104-109
Author(s):  
Nikolai F. Kizim ◽  
Anastasiya E. Tarasenkova
Keyword(s):  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Aqueous Phase ◽  
Equilibrium Constants ◽  
Material Balance ◽  
Mass Action ◽  
Acid Extraction ◽  
Processes And Reactions ◽  
Ionic Equilibria

The extraction of phosphoric acid with a solution of tri-n-butyl phosphate (TBP) in toluene from its individual aqueous solutions in a concentration range of 0-11 M is investigated. The experiments are performed at room temperature (20 ± 1 °С). The isotherms of extraction of phosphoric acid under conditions of equality of the volumes of the saturating aqueous phase and the receiving organic phase are constructed. The extraction isotherm is nonlinear, but to an acid concentration in the aqueous phase of ~ 8 M, it is close to linear, and at higher concentrations, the amount of extracted acid increases harshly. To establish the mechanism of acid extraction in the system phosphoric acid – 0.1 M solution of TBP in toluene the method of combining a laboratory and computational experiment is proposed. The optimal parameters describing the extraction of phosphoric acid from natural aqueous solutions are determined. Calculations performed in two approximations were made. In the first approximation the condition of ideality of systems is accepted. In the second approximation the deviations of the properties of phosphoric acid solutions in aqueous solution are taken into account. For the two approximations the preferential extraction of phosphoric acid molecules in the form of H3PO4 ∙ nTBP type solvates (where n = 1, 3) is shown. In the range of concentrations of phosphoric acid in the aqueous phase from 6 to 11 M, the values of equilibrium constants are estimated, which describe the processes and reactions occurring in the system: stepwise dissociation of acid, distribution of TBP, formation of solvates of phosphoric acid, distribution of the resulting solvates of acid, displacement of ionic equilibria in aqueous phase. Mathematically these processes are taken into account using the law of mass action and the equations of material balance. It is believed that the system has established an equilibrium corresponding to a given temperature and pressure. The calculated values of solvate concentrations are in satisfactory agreement with experimental data.

Application of Chelating Ion Exchanger Ostsorb DTTA to Determination of Lead and Cadmium in Soils, Plants, and Fertilizers

1994 ◽  
Vol 59 (3) ◽  
pp. 558-568 ◽  
Author(s):  
Ladislav Svoboda ◽  
Miloslav Tomek ◽  
Petr Tolar
Keyword(s):  
Functional Groups ◽  
Ion Exchanger ◽  
Plant Materials ◽  
Lead And Cadmium

The paper investigates a possible application of chelating cellulose ion exchanger with the functional groups of diethylenetriaminetetraacetic acid to concentrating lead and cadmium in extracts from soils and industrial fertilizers or mineralizates of plant materials. A favourable recovery of the metals needs the knowledge of the approximate content of the complex forming cations in the solutions and the suppression of formation of iron and aluminium hydroxides during modification of acidity of extracts to the value of pH 4 which is the optimum for the formation of chelates. The degree of concentrating reached the values of fE = 10 - 50, the recovery of lead and cadmium depended on the nature of sample and was in the range of R = 60 - 100%.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb DITHIZON and Ostsorb SALICYL

1994 ◽  
Vol 59 (6) ◽  
pp. 1319-1325 ◽  
Author(s):  
Ladislav Svoboda ◽  
Stanislav Jech
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Exchange Capacity ◽  
Ion Exchanger ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Metal Concentrations ◽  
Cadmium And Lead

The pH and I (ionic strength) dependences of exchange capacity of chelating ion exchangers Ostsorb based on spherical cellulose modified with functional groups of dithizone and salicylic acid have been studied in the sorption of Pb(II) and Cd(II) ions. The cellulosic selective sorbents Ostsorb DITHIZON and Ostsorb SALICYL can be used for sorption of Pb(II) and Cd(II) ions from aqueous solutions of I = 0 - 1 mol l-1 (Pb) and I = 0 - 5 mol l-1 (Cd); the dithizone ion exchanger retains both metals most effectively at pH 7 - 8, the salicyl ion exchanger at pH 5.5 - 6.5 (Pb) or pH 4 - 9 (Cd). Because of the formation of precipitates of hydrolytic products of the two metals in neutral and alkaline media, it is suitable to carry out the sorption in media of mild acidity if possible, particularly so at the metal concentrations above 1 mg l-1. Increasing ionic strength affects the exchange capacity for both metals in a negative way.

EINE CHEMISCHE METHODE ZUR BESTIMMUNG VON 16-EPI-ÖSTRIOL IM URIN DES MENSCHEN

1963 ◽  
Vol 44 (1) ◽  
pp. 47-66 ◽  
Author(s):  
W. Nocke ◽  
H. Breuer
Keyword(s):  
Melting Point ◽  
Phosphoric Acid ◽  
Aqueous Alkali ◽  
Percentage Error ◽  
Organic Layer ◽  
Maximum Percentage ◽  
Chemical Determination ◽  
Routine Assay ◽  
Hydrolysis Of

ABSTRACT A method for the chemical determination of 16-epi-oestriol in the urine of nonpregnant women with a qualitative sensitivity of less than 0.5 μg/24 h is described. The separation of 16-epi-oestriol and oestriol is accomplished by converting 16-epi-oestriol into its acetonide, a reaction which is stereoselective for cis-glycols and therefore not undergone by oestriol as a trans-glycol. Following partition between chloroform and aqueous alkali, the acetonide of 16-epi-oestriol is completely separated with the organic layer whereas oestriol as a strong phenol remains in the alkaline phase. 16-epi-oestriol is chromatographed on alumina as the acetonide and determined as a Kober chromogen. This procedure can easily be incorporated into the method of Brown et al. (1957 b) thus making possible the simultaneous routine assay of oestradiol-17β, oestrone, oestriol and 16-epi-oestriol from one sample of urine. The specificity of the method was established by separation of 16-epi-oestriol from nonpregnancy urine as the acetonide, hydrolysis of the acetonide by phosphoric acid, isolation of the free compound by microsublimation and identification by micro melting point, colour reactions and chromatography. The accuracy of the method is given by a mean recovery of 64% for pure crystalline 16-epi-oestriol when added to hydrolysed urine in 5–10 μg amounts. The precision is given by s = 0.24 μg/24 h. For the duplicate determination of 16-epi-oestriol the qualitative sensitivity is 0.44 μg/24 h, the maximum percentage error being ± 100% The quantitative sensitivity (±25% error) is 1.7 μg/24 h.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

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