Solubilisation of Ni(II) and Eu(III) through complexation with a polyaryl ether based superplasticizer in alkaline media

Alexander N Chernyshev; Annika C Maier; Mats Jonsson; Kerstin Forsberg

doi:10.1016/j.chemosphere.2020.127686

Solubilisation of Ni(II) and Eu(III) through complexation with a polyaryl ether based superplasticizer in alkaline media

Chemosphere. 2021 Jan:263:127686. doi: 10.1016/j.chemosphere.2020.127686. Epub 2020 Jul 21.

Authors

Alexander N Chernyshev¹, Annika C Maier², Mats Jonsson³, Kerstin Forsberg⁴

Affiliations

¹ Department of Chemical Engineering, KTH Royal Institute of Technology, Teknikringen 42, SE-100 44, Stockholm, Sweden. Electronic address: aleche@kth.se.
² Department of Chemistry, KTH Royal Institute of Technology, Teknikringen 30, SE-100 44, Stockholm, Sweden. Electronic address: acmaier@kth.se.
³ Department of Chemistry, KTH Royal Institute of Technology, Teknikringen 30, SE-100 44, Stockholm, Sweden. Electronic address: matsj@kth.se.
⁴ Department of Chemical Engineering, KTH Royal Institute of Technology, Teknikringen 42, SE-100 44, Stockholm, Sweden. Electronic address: kerstino@kth.se.

PMID: 33296996
DOI: 10.1016/j.chemosphere.2020.127686

Abstract

Solubilisation of Ni(II) and Eu(III) by complexation with a polyaryl ether based superplasticizer (PAE SP) in alkaline solutions was studied. The solubilisation was investigated in two types of artificial cement pore waters simulating different stages of cement degradation at a pH of 12.4 and 13.3, respectively. The solubility of Ni(II) and Eu(III) increased as the concentration of superplasticizer was increased from 0.04 to 0.4 wt%. When the concentration of SP was increased from 0.4 to 4%, the solubility of Eu(III) and Ni(II) increased in the pore water with a pH of 12.4, while the concentrations decreased in the pore water with a pH of 13.3. This is explained by a more rapid degradation of the superplasticizer at higher pH leading to a release of phosphate groups and thereby precipitation of Eu(III) and Ni(II) as phosphates. Based on results of the solubilisation of Ni(II) and Eu(III) by model compounds (anisole and PEG 400) and ³¹P NMR spectroscopy it was confirmed that the complexation of the studied metals with the PAE polymer occurs via the phosphate group of the superplasticizer.

Keywords: Polyaryl ether based superplasticizer; Radionuclide mobility; Waste disposal.

MeSH terms

Ether*
Hydrogen-Ion Concentration
Metals*
Phosphates
Solubility

Substances

Metals
Phosphates
Ether