Extraction of hexavalent uranium from citrate medium by the toluene solution of trilaurylamine

1983 ◽  
Vol 48 (1) ◽  
pp. 41-51
Author(s):  
Petr Vaňura ◽  
Libor Kuča
Keyword(s):  
Citric Acid ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Equilibrium Concentration ◽  
Toluene Solution ◽  
Hexavalent Uranium

Complexes of the type (UO2HA)p(TLA)q(H3A)r are formed in the extraction of uranyl by the toluene solutions of trilaurylamine (TLA) from the isomolar aqueous phase formed by 1M-(H, Na,(UO2)0.5)3A, where H3A is citric acid. The extraction was studied at pH 1.62 with the equilibrium concentration of uranium in the aqueous phase in the range 10-4 -10-1 mol l-1 and with TLA concentration in the organic phase ranging from 0.0305 to 0.308 mol l-1. Complexes with q=5 and p+r=3 predominate in the extraction by TLA solutions of lower concentrations (c(TLA) = 0.0305 mol l-1). The fraction of more associated complexes (q=8-9, q - (p+r=0-2) increase with the increase of TLA concentration.

Extraction of iron(III) from the citric medium by the toluene solution of trilaurylamine

1980 ◽  
Vol 45 (11) ◽  
pp. 3116-3129 ◽  
Author(s):  
Petr Vaňura ◽  
Libor Kuča
Keyword(s):  
Citric Acid ◽  
Ionic Strength ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Toluene Solution ◽  
Constant Ionic Strength ◽  
Extraction Constants ◽  
Equilibrium Concentrations

The composition of Fe(III) complexes extracted from the aqueous phase of constant ionic strength (1M-(H3,Na3,Fe)A, where H3A denotes citric acid) by the toluene solution of trilaurylamine (TLA) has been determined and the respective extraction constants have been calculated. In the concentration range cFe < 10-2 mol l-1 FeA(TLA)2 and FeA(TLA)4(H3A)2-4 are the predominant complexes in the organic phase. The abundance of the (FeA)3(TLA)6(H3A)2 complex in the organic phase increases at higher equilibrium concentrations of Fe(III) in the aqueous phase and at higher concentrations of TLA.

Extraction of hafnium(IV) with organophosphorus reagents from solutions of mineral acids mixtures

1979 ◽  
Vol 44 (12) ◽  
pp. 3656-3664
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola ◽  
Rostislav Kolouch
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Synergic Effect ◽  
Salting Out ◽  
Initial Concentration ◽  
Mixed Complexes ◽  
Synergic Extraction ◽  
Mineral Acids

Extraction of hafnium(IV) was studied from solutions of mixtures of perchloric and nitric acids and of perchloric and hydrochloric acids for constant ionic strength, I = 2, 4, 6, or 8, and for cHf 4 . 10-4 mol l-1. The organic phase was constituted by solutions of some acidic or neutral organophosphorus reagents or of 2-thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, or N-benzoyl-N-phenylhydroxylamine in benzene, chloroform, or n-octane. A pronounced synergic extraction of hafnium proceeds only on applying organophosphorus reagents from an aqueous phase whose acidity is not lower than 3M-(HClO4 + HNO3) or 5M-(HClO4 + HCl). The synergic effect was not affected markedly by a variation of the initial concentration of hafnium in the range 1 . 10-8 -4 .10-4 mol l-1, it lowered with increasing initial concentration of the organophosphorus reagent and decreasing concentration of the H+ ions. It is suggested that the hafnium passes into the organic phase in the form of mixed complexes, the salting-out effect of perchloric acid playing an appreciable part.

scholarly journals Aspergillus piperis A/5 from plum-distilling waste compost produces a complex of antifungal metabolites active against the phytopathogen Pythium aphanidermatum

2016 ◽  
Vol 68 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Jelena Jovicic-Petrovic ◽  
Sanja Jeremic ◽  
Ivan Vuckovic ◽  
Sandra Vojnovic ◽  
Aleksandra Bulajic ◽  
...  
Keyword(s):  
Citric Acid ◽  
Solvent Extraction ◽  
Antifungal Activity ◽  
Aqueous Phase ◽  
Plant Pathogens ◽  
Complex Mixture ◽  
Pythium Aphanidermatum ◽  
Disease Suppression ◽  
Antifungal Metabolites ◽  
Culture Extract

Adding compost to soil can result in plant disease suppression through the mechanisms of antagonistic action of compost microflora against plant pathogens. The aim of the study was to select effective antagonists of Pythium aphanidermatum from compost, to assess the effect of its extracellular metabolites on the plant pathogen, and to characterize antifungal metabolites. The fungal isolate selected by a confrontation test was identified as Aspergillus piperis A/5 on the basis of morphological features and the internal transcribed spacer (ITS) region, ?-tubulin and calmodulin partial sequences. Liquid chromatography-mass spectroscopy (LC-MS) analysis showed that gluconic and citric acid were the most abundant in the organic culture extract. However, the main antifungal activity was contained in the aqueous phase remaining after the organic solvent extraction. The presence of considerable amounts of proteins in both the crude culture extract as well as the aqueous phase remaining after solvent extraction was confirmed by SDS-PAGE. Isolated Aspergillus piperis A/5 exhibits strong antifungal activity against the phytopathogen Pythium aphanidermatum. It secretes a complex mixture of metabolites consisting of small molecules, including gluconic acid, citric acid and itaconic acid derivatives, but the most potent antifungal activity was associated with proteins resistant to heat and organic solvents. Our findings about the activity and characterization of antagonistic strain metabolites contribute to the understanding of the mechanism of interaction of antifungal metabolites as well as fungal-fungal interaction. The obtained results provide a basis for further application development in agriculture and food processing.

Citric acid modified Ni3P as a catalyst for aqueous phase reforming and hydrogenolysis of glycerol to 1,2-PDO

2021 ◽  
Author(s):  
Tianyu Hu ◽  
Zhiquan Yu ◽  
Shan Liu ◽  
Bingyu Liu ◽  
Zhichao Sun ◽  
...  
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Aqueous Phase ◽  
Small Particle ◽  
Small Particle Size ◽  
Temperature Programmed Reduction ◽  
Aqueous Phase Reforming ◽  
Temperature Programmed ◽  
Co Precipitation

Citric acid (CA) modified Ni3P catalysts with small particle size were prepared by H2 temperature-programmed reduction (H2-TPR) of the precursors, which were prepared by co-precipitation with Ni(NO3)2·6H2O and (NH4)2HPO4, using...

Recovery of Uranium (VI) from Water Solutions by Membrane Extraction

2013 ◽  
Vol 704 ◽  
pp. 66-71
Author(s):  
Grazyna Zakrzewska ◽  
Pawel Bieluszka ◽  
Ewelina Chajduk ◽  
Stanislaw Wolkowicz
Keyword(s):  
Aqueous Phase ◽  
Organic Phase ◽  
Extraction Efficiency ◽  
Membrane Extraction ◽  
Membrane Contactor ◽  
Shell Side ◽  
Real Solutions ◽  
Model Solutions ◽  
Capillary Membrane ◽  
Capillary Membranes

The extraction of uranium from aqueous model solutions, as well as from real solutions reulting from leaching uranium ores was carried out in the system equipped with the Liqui-Cel® Extra-Flow membrane contactor with polypropylene capillary membranes. D2EHPA in toluene was used as an organic phase. Different arrangements of flow inside the membrane module were tested. The better approach appeared to be the arrangement with aqueous phase in the shell side of the contactor and organic phase inside the capillary membrane. The extraction efficiency for model solutions reached 95% and 87% for real post-leaching liquors.

The extraction of cobalt(II) from lithium chloride solutions by aliquat 336R dissolved in chloroform

1982 ◽  
Vol 35 (11) ◽  
pp. 2345 ◽  
Author(s):  
R Paimin ◽  
RW Cattrall
Keyword(s):  
Ion Exchange ◽  
Aqueous Phase ◽  
Lithium Chloride ◽  
Organic Phase ◽  
Equilibrium Constants ◽  
Single Drop ◽  
Chloride Solutions ◽  
Rate Determining Step ◽  
Fast Ion ◽  
Drop Technique

The extraction of cobalt(II) by Aliquat 336R from 7 M lithium chloride solutions involves two species from the aqueous phase, COCl42 and CoCl3-, with the former being the predominant one. The equilibrium constants for the formation of the extracted complexes (R3MeN+)2 CoCl42- and R3MeN+CoCI3- are: logKll 5.01 and logK12 9.55. From the results of experiments by means of the single-drop technique, a mechanism is proposed based on the formation of interfacial complexes by fast ion-exchange with a rate-determining step which involves the replacement at the interface of the complex (R3MeN+)2 COCl42- by two molar proportions of reagent from the bulk organic phase.

Sign in / Sign up

Export Citation Format

Share Document