Association of europium(III), americium(III), and curium(III) with cellulose, chitin, and chitosan

Abstract

The association of trivalent f-elements-Eu(III), Am(III), and Cm(III)--with cellulose, chitin, and chitosan was determined by batch experiments and time-resolved, laser-induced fluorescence spectroscopy (TRLFS). The properties of these biopolymers as an adsorbent were characterized based on speciation calculation of Eu(III). The adsorption study showed that an increase of the ionic strength by NaCl did not affect the adsorption kinetics of Eu(III), Am(III), and Cm(III) for all the biopolymers, but the addition of Na2CO3 significantly delayed the kinetics because of their trivalent f-element complexation with carbonate ions. It also was suggested from the speciation calculation study that all the biopolymers were degraded under alkaline conditions, leading to their masking of the adsorption of Eu(III), Am(III), and Cm(III) on the nondegraded biopolymers. The masking effect was higher for cellulose than for chitin and chitosan, indicating that of the three, cellulose was degraded most significantly in alkaline solutions. Desorption experiments suggested that some portion of the adsorbed Eu(III) penetrated deep into the matrix, being isolated in a cavity-like site. The TRLFS study showed that the coordination environment of Eu(III) is stabilized mainly by the inner spherical coordination in chitin and by the outer spherical coordination in chitosan, with less association in cellulose in comparison to chitin and chitosan. These results suggest that the association of these biopolymers with Eu(III), Am(III), and Cm(III) is governed not only by the affinity of the functional groups alone but also by other factors, such as the macromolecular steric effect. The association of degraded materials of the biopolymers also should be taken into consideration for an accurate prediction of the influence of biopolymers on the migration behavior of trivalent f-elements.

Plant cell (Brassica napus) response to europium(III) and uranium(VI) exposure

“…EDTA: ethylenediaminetetraacetic acid, LPS: lipopolysaccharide. References: (a) Moll et al 2014 , (b) Ozaki et al 2005 , (c) Ozaki et al 2006 , (d) Heller et al 2012 , (e) Barkleit et al 2013 , (f) Bader et al 2019 …”

New Effective Sorbents for Removal of Am-241 from Drinking Water

“…log (q e −q t ) = log q e -(k 1 /2.303) • t (5) …where q e and q t are the amount of Am ions adsorbed at equilibrium in mol/g and at time t in min, respectively, and k 1 is the pseudo-first-order rate constant (1/min). Lagergren's first-order rate constant (k 1 ) and q e determined from the model are shown in Table 2 along with the corresponding correlation coefficients.…”

Phosphate-Mediated Remediation of Metals and Radionuclides

“…Chemical and physical methods, including excavation and soil capping [21,22], pump and treat technologies [23,24], mineral adsorption [25][26][27], mineral precipitation [28,29], complexation [30][31][32], adsorption to permeable zero-valent iron and hydroxyapatite reactive barriers [33][34][35], cement solidification [36,37], and vitrification [38,39], have all demonstrated efficacy in mitigating contaminant transport in situ. Remediation methods that depend upon chemical transformations for in situ sequestration of contaminants must first consider local geochemical parameters that include local geology, concentrations of soluble anions and cations, pH, and redox state.…”