Electrochemical, spectroscopic, and thermal studies on interactions of linear poly(acrylic acid) with uranyl ions in aqueous solutions

Abstract

ABSTRACT:The formation of complexes between linear poly(acrylic acid) (PAA) and uranyl ions in aqueous solutions was studied with conductometry, potentiometry, thermal analysis, Fourier transform infrared, and luminescence spectroscopy methods. The stoichiometry of the PAA/UO 2 2ϩ complex on repeating units of a PAA basis was determined to be 2:1. IR spectroscopy studies made on solid complexes showed that the carbonyl stretching absorption band of PAA was shifted to a higher wave number, and a new band at 1749 cm Ϫ1 in the polycomplex spectrum was observed, confirming the existence of specific interactions between the carboxylate groups of PAA and metal ions. Luminescence spectroscopy studies showed an increase in the intensity of the uranyl-ion emission spectra and new band formation at 483 nm, further confirming the interaction of UO 2 2ϩ ions with PAA in aqueous solutions. The thermal behavior of PAA/UO 2 2ϩ complexes further proved strong interactions in the complex structure. The thermal degradation of the polycomplexes included the main stages of destruction of both PAA and uranyl nitrate.

Complex formation of linear poly(methacrylic acid) with uranyl ions in aqueous solutions

“…Also, additional shoulders appear at around 465 nm. The observations of increased emission intensity at higher PMAA concentration are not similar to luminescence results obtained for PAA-UO 2+ 2 aqueous solutions [25], which are likely to be related to the influence of conformation peculiarities of PMAA chains. It is known that in aqueous solutions PMAA macromolecules take a more compact conformation with decreased pH [21,26], and hydrophobic associations become stronger [27].…”

Factors affecting the complexation of polyacrylic acid with uranyl ions in aqueous solutions: A luminescence study

“…In our previous study19 the mechanism of interaction between PAA and uranyl ions in aqueous solutions and the restrictive role of Coulombic interactions were confirmed using conductometric, potentiometric, thermal analysis, and FT‐IR spectroscopic methods. In this study, we tried to show the effect of some factors such as pH, salt concentration, and temperature on luminescence properties of UO ions complexed with PAA in aqueous solutions.…”

Temperature‐ and pH‐Sensitive Nanocomposite Gels with Semi‐Interpenetrating Organic/Inorganic Networks

“…This absorption band was ascribed to the anti-symmetric vibration signal of COO À caused by the ionization of the carboxylic groups of PAA. [29,30] The appearance of an anti-symmetric vibration signal was also observed in AA/clay systems. So, it was concluded that PAA (or AA) and clay formed complexes via strong hydrogen bonds formed as a result of the transference of protons from the carboxylic groups of PAA to the clay surface.…”