Cesium and barium removal from aqueous solutions in the presence of humic acid and competing cations by a Greek bentonite from Kimolos Island

Fotini Noli; Victoria Fedorcea; Panagiotis Misaelides; Igor Cretescu; Maria Kapnisti

doi:10.1016/j.apradiso.2021.109600

Cesium and barium removal from aqueous solutions in the presence of humic acid and competing cations by a Greek bentonite from Kimolos Island

Appl Radiat Isot. 2021 Apr:170:109600. doi: 10.1016/j.apradiso.2021.109600. Epub 2021 Jan 21.

Authors

Fotini Noli¹, Victoria Fedorcea², Panagiotis Misaelides³, Igor Cretescu⁴, Maria Kapnisti⁵

Affiliations

¹ Department of Chemistry, Aristotle University, GR-54124, Thessaloniki, Greece. Electronic address: noli@chem.auth.gr.
² Department of Chemistry, Aristotle University, GR-54124, Thessaloniki, Greece; Faculty of Chemical Engineering and Environmental Protection, Gheorghe Asachi Technical University of Iasi, 700050, Iasi, Romania.
³ Department of Chemistry, Aristotle University, GR-54124, Thessaloniki, Greece.
⁴ Faculty of Chemical Engineering and Environmental Protection, Gheorghe Asachi Technical University of Iasi, 700050, Iasi, Romania.
⁵ Department of Food Science and Technology, International Hellenic University, P.O. Box141, GR-57400, Thessaloniki, Greece.

PMID: 33548812
DOI: 10.1016/j.apradiso.2021.109600

Abstract

The Cs- and Ba-sorption, onto bentonite from Kimolos island (Cyclades, Greece) was investigated in aqueous solutions in the presence of Na⁺, Ca²⁺ and humic acid. Batch experiments were performed using as tracers ¹³⁷Cs and ¹³³Ba and γ-ray spectroscopy. The sorption significantly depended on initial concentration, ionic strength and temperature of the solutions. The sorption isotherms were satisfactorily reproduced by the Langmuir and Freundlich equations. The kinetic experiments at 293, 308 and 323 K and the calculation of the thermodynamic parameters (ΔH, ΔS° and ΔG°) indicated that Cs- and Ba-sorption was spontaneous and endothermic process. The sorbent was characterized before and after the sorption experiments using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM-EDS). It was demonstrated that the Kimolos bentonite is a good sorbent for cesium and barium from highly contaminated solutions and its sorption capacity reduced in presence of humic acid and competing cations.

Keywords: Bentonite; Cs- and Ba-Uptake; Isotherms; Kinetics; Sorption.