Individual extraction constants of univalent ions in the system water-nitrobenzene

1971 ◽  
Vol 36 (9) ◽  
pp. 3253-3262 ◽  
Author(s):  
J. Rais
Keyword(s):  
Extraction Constants ◽  
Individual Extraction Constants ◽  
System Water

The Extraction of Strontium and Barium with a Solution of Bis-1,2-Dicarbollylcobaltate in Nitrobenzene in the Presence of 18-Crown-6

1993 ◽  
Vol 58 (6) ◽  
pp. 1324-1336 ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Extraction Constants ◽  
Individual Extraction Constants

A study has been made of the extraction of Sr and Ba in an aqueous solution of perchloric acid-18-crown-6-bis-1,2-dicarbollylcobaltate-nitrobenzene. It was found that the organic phase contains complexes of the ML2+org type ( M = Sr2+, Ba2+) that are converted to ML22+org when the concentration of crown (cL) is greater than the concentration of bis-1,2-dicarbollylcobaltate (cB). The values of the corresponding extraction constants, individual extraction constants and stability constants of the extracted species in the organic phase were determined. The system can be utilized for separation applications at concentrations here cL < cB.

Contribution to the thermodynamics of complexes of alkali metal cations with dibenzo-18-crown-6 in water-nitrobenzene extraction system

1984 ◽  
Vol 49 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Emanuel Makrlík ◽  
Jaroslava Hálová ◽  
Miroslav Kyrš
Keyword(s):  
Alkali Metal ◽  
Alkali Metal Cation ◽  
Alkali Metal Cations ◽  
Complex Species ◽  
Cation Order ◽  
Extraction Constants ◽  
Equilibrium Data ◽  
Individual Extraction Constants ◽  
The Stability ◽  
The Individual

The stability constants for the ML+ complex species, where M+ is an alkali metal cation and L is dibenzo-18-crown-6, in nitrobenzene saturated with water were calculated by employing published equilibrium data. The stability is found to increase in the cation order Li+ < Cs+ < Rb+ < K+ < Na+. For the NaL+, KL+, RbL+, and CsL+ complex cations the individual extraction constants in the water-nitrobenzene system were determined; their values increase in the series Na+ < K+ < Rb+ < Cs+.

The Extraction Transfer of H+-18-Crown-6 Species across the Water-Nitrobenzene Phase Boundary in the Extraction of Aqueous Solutions of Perchloric Acid by Nitrobenzene in the Presence of 18-Crown-6

1993 ◽  
Vol 58 (3) ◽  
pp. 483-495 ◽  
Author(s):  
Petr Vaňura ◽  
Iveta Juklíková
Keyword(s):  
Experimental Data ◽  
Phase Boundary ◽  
Perchloric Acid ◽  
Free Enthalpy ◽  
Nitrobenzene Phase ◽  
Extraction Constants ◽  
L Systems ◽  
Individual Extraction Constants ◽  
The Individual ◽  
The Given

A study was made of the extraction of perchloric acid in water-nitrobenzene-18-crown-6 (hereafter L) systems. The experimental data was interpreted on the basis of the assumption that the extraction occurs according the equations H+aq + ClO4,aq- ↔ H+org + ClO4,org- and H+aq + Laq + ClO4,aq- ↔ HL+org + ClO4,org-. Crown is also protonated in the aqueous phase according to the equation H+aq + Laq ↔ HL+aq. The values of the corresponding extraction constants, the protonation constants of 18-crown-6 in nitrobenzene and water and the individual extraction constants of the HL+ species in the water-nitrobenzene system were determined, along with the magnitude of the molar free enthalpy for the transfer of these species across the given phase boundary.

Individual extraction constants of some dicarbollylcobaltate anions in the water-nitrobenzene system

1995 ◽  
Vol 198 (2) ◽  
pp. 359-365 ◽  
Author(s):  
E. Makrlík ◽  
J. Rais ◽  
K. Baše ◽  
J. Plešek ◽  
P. Vaňura
Keyword(s):  
Extraction Constants ◽  
Individual Extraction Constants

ANALYSIS OF ACCUMULATION AND DISTRIBUTION OF LEAD IN THE SYSTEM WATER-BOTTOM SEDIMENTS IN THE BACH DANG ESTUARY (VIETNAM)

2017 ◽  
pp. 62-66
Author(s):  
Truong Van Tuan ◽  
Irina Vladimirovna Volkova
Keyword(s):  
Bottom Sediment ◽  
Bottom Sediments ◽  
Water Samples ◽  
Suspended Solids ◽  
Natural Habitat ◽  
Bottom Layer ◽  
Sediment Samples ◽  
Natural Breeding ◽  
System Water ◽  
Water Bottom

Research was held in the estuary of the river Bach Dang (Dongbay community, Rakhtay district, Hai Phong, Vietnam) in June, 2012 - May, 2013. Concentration of lead was studied in water, suspended solids and bottom sediment. Clam beach (natural breeding environment of Meretrix lyrata ) was inspected regularly, every month. Water samples were taken 6 times from the bottom layer 10 cm down the bottom, once per 3 hours in each of 12 investigated zones. Bottom sediment samples were taken at the depth 2 cm. The findings show that lead accumulates mainly in suspended solids (23.3 mg/kg) and in bottom sediment (14.31 mg/kg), in water it is in small quantities (0.003 mg/kg). Analysis of bottom sediment samples taken in different places showed that they have even leadcontent, lead is distributed uniformly, localization of contaminations is not found. The results obtained can be assumed as the basis for investigating lead accumulation and its excretion by clam Meretrix lyrata organisms in the natural habitat.

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