Sequestering ability of polyaminopolycarboxylic ligands towards dioxouranium(VI) cation

Stefano, Concetta De; Gianguzza, Antonio; Milea, Demetrio; Pettignano, Alberto; Sammartano, Silvio

doi:10.1016/j.jallcom.2006.01.003

Cited by 34 publications

(19 citation statements)

References 35 publications

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“…As shown in Figure S5, the adsorption of U(VI) on TiO 2 /Fe 3 O 4 in the dark similarly increased with the increase of solution pH, suggesting that in adsorbed U(VI)–EDTA complexes, UO 2 2+ should interact with the composite surface . However, the adsorption percentage of U(VI) was only 36.4% even at pH 8.3, the reason could be related with the strong coordination affinity of EDTA with U(VI), which may weaken the interaction of the material surface with U(VI) . Upon UV irradiation, residual U(VI) (%) decreased rapidly and after the photocatalysis, around 5.6% of the total uranium was left in the solutions at all pH, we have examined.…”

Section: Resultssupporting

confidence: 86%

“…40 However, the adsorption percentage of U(VI) was only 36.4% even at pH 8.3, the reason could be related with the strong coordination affinity of EDTA with U(VI), which may weaken the interaction of the material surface with U(VI). 41 Upon UV irradiation, residual U(VI) (%) decreased rapidly and after the photocatalysis, around 5.6% of the total uranium was left in the solutions at all pH, we have examined. The pH f was found to be approximately 8.5, regardless of the initial solution pH, which is in good agreement with the results on pure EDTA degradation photocatalyzed by P25 TiO 2 .…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

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Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO₂/Fe₃O₄ and Its Graphene Composite

Huang

Guo

et al. 2017

Environ. Sci. Technol.

324

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The separation and recovery of uranium from radioactive wastewater is important from the standpoints of environmental protection and uranium reuse. In the present work, magnetically collectable TiO 2 /Fe 3 O 4 and its graphene composites were fabricated and utilized for the photocatalytical removal of U(VI) from aqueous solutions. It was found that, under ultraviolet (UV) irradiation, the photoreactivity of TiO 2 /Fe 3 O 4 for the reduction of U(VI) was 19.3 times higher than that of pure TiO 2 , which is strongly correlated with the Fe 0 and additional Fe(II) generated from the reduction of Fe 3 O 4 by TiO 2 photoelectrons. The effects of initial uranium concentration, solution pH, ionic strength, the composition of wastewater, and organic pollutants on the U(VI) removal by TiO 2 /Fe 3 O 4 were systematically investigated. The results demonstrated its excellent performance in the cleanup of uranium contamination. As graphene can efficiently attract the TiO 2 photoelectrons and thus decrease their transfer to Fe 3 O 4 , the photodissolution of Fe 3 O 4 in the TiO 2 /graphene/Fe 3 O 4 composite can be largely alleviated compared to that of the TiO 2 /Fe 3 O 4 , rendering this ternary composite a much higher stability. In addition, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray absorption near edge spectroscopy (XANES), and X-ray photoelectron spectroscopy (XPS) were used to explore the reaction mechanisms.

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Section: Resultssupporting

confidence: 86%

Section: ■ Experimental Methodsmentioning

confidence: 99%

Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO₂/Fe₃O₄ and Its Graphene Composite

Huang

Guo

et al. 2017

Environ. Sci. Technol.

324

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“…The stability data obtained for the species formed in the different Pd 2+ –APC systems allowed us to assess the different sequestering capacity of the five complexones used toward the palladium(II) ion in the pH range investigated. To this end the pL 50 parameter, already tested successfully for other metal–ligand systems, − was used. This parameter gives quantitative information on the sequestration capability of a ligand toward metal ions at fixed experimental conditions of pH and ionic strength.…”

Section: Introductionmentioning

confidence: 99%

Palladium(II) Complexes of Aminopolycarboxylic Ligands in Aqueous Solution

et al. 2011

Self Cite

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The binding capacity of five aminopolycarboxylic ligands (APCs) [nitrilotriacetate (NTA), ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), (S,S)-ethylenediamine-N,N′-disuccinic acid (S,S-EDDS), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA), and triethylenetetraamine-N,N,N′,N″,N‴,N‴-hexaacetate (TTHA)] toward the palladium(II) ion was studied by potentiometric titrations (ISE-H+ electrode) in NaNO3 and in NaClO4/NaI (at different molar ratios) solutions and by spectrophotometric titrations (only in NaClO4), at I = 0.1 mol·kg–1 and at T = 298.15 K. The high stability of Pd2+-complexones species inhibits the formation of sparingly soluble hydroxo species until pH 11. In the pH range investigated and at the Pd2+/APC ratios used in the experiments (1/1–1/4), all of the complexones form with palladium(II) only protonated or unprotonated mononuclear species and the monohydroxo species Pd(APC)(OH). As consequence of the ligand structure and of the number of amino and carboxylic groups involved in the coordination, the stability of palladium(II)–APC species follows the trend: TTHA > DTPA > EDTA > S,S-EDDS > NTA; for example, the log K PdL is 37.00, 36.31, 23.60, 23.07, and 17.82 for L = TTHA, DTPA, EDTA, S,S-EDDS, and NTA, respectively. A critical evaluation of literature evidenced the big discrepancies in stability data and also in the speciation models proposed by different authors. A comparison of the sequestering capacity of complexones toward palladium(II) and other divalent metal ions was done by using stability data from this work and literature ones.

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“…Meanwhile, the hydrolysis process takes place in a wide pH range, competing with other complexation reactions. Among the ligands, short‐chain organic acids attract extensive interest , because of their wide distribution in the geosphere and biosphere, high chelating ability provided by carboxyl groups, and low toxicity for pharmaceutical uses. As citric acid is a common constituent of the ecosystem and appears in multiple living organisms, the study of uranyl complexation with citrate bears extraordinary importance.…”

Section: Introductionmentioning

confidence: 99%

Binding constant determination of uranyl–citrate complex by ACE using a multi‐injection method

Zhang

Huang³

et al. 2015

Electrophoresis

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The binding constant determination of uranyl with small-molecule ligands such as citric acid could provide fundamental knowledge for a better understanding of the study of uranyl complexation, which is of considerable importance for multiple purposes. In this work, the binding constant of uranyl-citrate complex was determined by ACE. Besides the common single-injection method, a multi-injection method to measure the electrophoretic mobility was also applied. The BGEs used contained HClO4 and NaClO4 , with a pH of 1.98 ± 0.02 and ionic strength of 0.050 mol/L, then citric acid was added to reach different concentrations. The electrophoretic mobilities of the uranyl-citrate complex measured by both of the two methods were consistent, and then the binding constant was calculated by nonlinear fitting assuming that the reaction had a 1:1 stoichiometry and the complex was [(UO2 )(Cit)](-) . The binding constant obtained by the multi-injection method was log K = 9.68 ± 0.07, and that obtained by the single-injection method was log K = 9.73 ± 0.02. The results provided additional knowledge of the uranyl-citrate system, and they demonstrated that compared with other methods, ACE using the multi-injection method could be an efficient, fast, and simple way to determine electrophoretic mobilities and to calculate binding constants.

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Sequestering ability of polyaminopolycarboxylic ligands towards dioxouranium(VI) cation

Cited by 34 publications

References 35 publications

Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO₂/Fe₃O₄ and Its Graphene Composite

Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO₂/Fe₃O₄ and Its Graphene Composite

Palladium(II) Complexes of Aminopolycarboxylic Ligands in Aqueous Solution

Binding constant determination of uranyl–citrate complex by ACE using a multi‐injection method

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Sequestering ability of polyaminopolycarboxylic ligands towards dioxouranium(VI) cation

Cited by 34 publications

References 35 publications

Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO2/Fe3O4 and Its Graphene Composite

Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO2/Fe3O4 and Its Graphene Composite

Palladium(II) Complexes of Aminopolycarboxylic Ligands in Aqueous Solution

Binding constant determination of uranyl–citrate complex by ACE using a multi‐injection method

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Product

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Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO₂/Fe₃O₄ and Its Graphene Composite

Enhanced Photocatalytic Removal of Uranium(VI) from Aqueous Solution by Magnetic TiO₂/Fe₃O₄ and Its Graphene Composite