Solubilisation of Ni(II) and Eu(III) through complexation with a polyaryl ether based superplasticizer in alkaline media. (January 2021)

• Record Type: Journal Article
• Authors: Chernyshev, Alexander N.; Maier, Annika C.; Jonsson, Mats; Forsberg, Kerstin
• Is Part Of: Chemosphere. Volume 263(2021)
• Publication Date: 2021-01
• Subjects: Waste disposal -- Polyaryl ether based superplasticizer -- Radionuclide mobility; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127686
• Languages: English
• ISSNs: 0045-6535

Abstract

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 31 P NMR spectroscopy it was confirmed that the complexation of the studied metals with the PAE polymer occurs via the phosphate group of the superplasticizer. Highlights: Ni(II) and Eu(III) form complexes with the phosphate group of the superplasticizer. Degradation of the superplasticizer leads to precipitation of metal phosphates. The results indicate that degradation is more rapid at higher pH.