Efficient uranium immobilization on red clay with phosphates.

Ewelina Grabias,Anna Książek,Marek Majdan,Agnieszka Gładysz-Płaska

doi:10.1007/s10311-013-0442-2

Ewelina Grabias, Anna Książek + Show 2 more

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https://doi.org/10.1007/s10311-013-0442-2

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Abstract

Uranium is a very toxic and radioactive element. Removal of uranium from wastewaters requires remediation technologies. Actual methods are costly and ineffective when uranium concentration is very low. Little is known about the enhancement of sorption of uranyl ions by phosphate ions on aluminosilicates. Here, we studied sorption of uranyl acetate on red clay in the presence of phosphates. The concentration of U(VI) ranged 0.0001–0.001 mol/L, whereas the concentration of PO4 3− was constant at 0.0001 mol/L. We designed a new method for the analysis of ternary surface complexes. We observed for the first time a remarkable improvement of U(VI) sorption on red clay under the influence of phosphates. We also found that at least two different ternary surface complexes U(VI)–phosphate–clay are formed in the sorbent phase. The complexation of UO2 2+ cations by phosphate ligands in the sorbent phase was confirmed by the X-ray photoelectron spectra of U 4f electrons.

Highlights

Uranium is a very toxic and radioactive element
Little is known about the enhancement of sorption of uranyl ions by phosphate ions on aluminosilicates
We found that at least two different ternary surface complexes U(VI)–phosphate–clay are formed in the sorbent phase

Summary

Introduction

Uranium is a very toxic and radioactive element. Low levels of it occur naturally in all rocks, soils, and waters (Shawky et al 2005). High concentrations of uranium are found in wastewaters near processing facilities. Several methods are applied to eliminate uranium from wastewaters and process effluents. The best known among them are reduction followed by chemical precipitation, ion exchange, electrochemical precipitation, solvent extraction, membrane separation, and biosorption (Konstantinou and Demetriou 2007). These methods, are costly and ineffective when uranium concentration is very low (Blazquez et al 2005). The results of several experimental studies have been published in this field (Aksoyoglu 1989; Ames et al 1983; Arnold et al 1998; Donat and Aytas 2005; Fuller et al 2003; Giammar 2001; Hongxia and Zuyi 2002; Kilincarslan and Akyil 2005; Baumann et al 2005; Wersin et al 1994; Waite et al 1994; Zhijun et al 2004; Zuyi et al 2000)

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