二氧铀（VI）-羧酸盐配合物。在25℃下不同离子强度的NaCl（水溶液）中UO2(2+) - 1,2,3 - 丙三羧酸盐体系的物种形成。

Dioxouranium(VI)-carboxylate complexes. Speciation of UO2(2+)-1,2,3-propanetricarboxylate system in NaCl(aq) at different ionic strengths and at t=25 degrees C.

作者信息

Crea Francesco, De Stefano Concetta, Milea Demetrio, Sammartano Silvio

机构信息

Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica dell'Università di Messina, Salita Sperone 31, 1-98166, Messina (Vill. S. Agata), Italy.

出版信息

Ann Chim. 2007 Mar-Apr;97(3-4):163-75. doi: 10.1002/adic.200790002.

DOI:10.1002/adic.200790002

PMID:17822225

Abstract

The formation constants of dioxouranium(VI)-1,2,3-propanetricarboxylate [tricarballylate (3-), TCA] complexes were determined in NaCl aqueous solutions at 0 < or = I/mol L(-1) < or = 1.0 and t=25 degrees C, by potentiometry, ISE-[H+] glass electrode. The speciation model obtained at each ionic strength includes the following species: ML-, MLH0, ML2(4-) and ML2H3- (M = UO2(2+) and L = TCA). The dependence on ionic strength of protonation constants of 1,2,3-propanetricarboxylate and of the metal-ligand complexes was modeled by the SIT (Specific ion Interaction Theory) approach and by the Pitzer equations. The formation constants at infinite dilution are [for the generic equilibrium p UO22+ + q (L3-) + r H+ = (UO2(2+))p(L)qHr(2p-3q+r); betapqr]: log beta110 = 6.222 +/- 0.030, log beta111 = 11.251 +/- 0.009, log beta121 = 7.75 +/- 0.02, log beta121 = 14.33 +/- 0.06. The sequestering ability of 1,2,3-propanetricarboxylate towards UO2(2+) was quantified by using a sigmoid Boltzman type equation.

摘要

在0≤I/mol L⁻¹≤1.0且t = 25℃的NaCl水溶液中，采用电位分析法、离子选择性电极-[H⁺]玻璃电极测定了二氧铀(VI)-1,2,3-丙三羧酸[三羧甲基丙烷(3-), TCA]配合物的形成常数。在每种离子强度下获得的物种形成模型包括以下物种：ML⁻、MLH₀、ML₂(4⁻)和ML₂H₃⁻（M = UO₂²⁺且L = TCA）。采用特定离子相互作用理论（SIT）方法和皮兹方程对1,2,3-丙三羧酸以及金属-配体配合物的质子化常数对离子强度的依赖性进行了建模。无限稀释时的形成常数[对于一般平衡p UO₂²⁺ + q (L³⁻) + r H⁺ = (UO₂²⁺)ₚ(L)qHr(2p - 3q + r)；βpqr]：log β110 = 6.222 ± 0.030，log β111 = 11.251 ± 0.009，log β121 = 7.75 ± 0.02，log β121 = 14.33 ± 0.06。通过使用S型玻尔兹曼型方程对1,2,3-丙三羧酸对UO₂²⁺的螯合能力进行了量化。