Complexing power of hydro-soluble degradation products from γirradiated polyvinylchloride: influence on Eu(OH)₃(s) solubility and Eu(III) speciation in neutral to alkaline environment

Abstract

<jats:title>Abstract</jats:title><jats:p>The complexing power of hydrosoluble degradation products (HDPs) from an alkaline hydrolysis of a 10 MGy γ-irradiated polyvinylchloride is studied. The complexation of Eu(III), as an analogue of lanthanide and actinide radionuclides at their +III oxidation state for oxygen containing functions, is evidenced both from the increasing of Eu(OH)</jats:p>

Influence of adipic acid on the speciation of Eu(III): Review of thermodynamic data in NaCl and NaClO4 media, and a new determination of Eu-adipate complexation constant in 0.5 mol·kgw−1 NaClO4 medium by time-resolved luminescence spectroscopy

“…supposedly mixed Eu(OH)nAdip (3-2-n)+ . But it must not be forgotten that in a previous work it has been shown that oxalate and glutarate -which are supposed to have greater complexation constants than adipate [13] -did not increase Eu(OH)3(s) solubility at pH 13.3 [38]. Even phthalic acid has not been shown to impact solubility of Eu(OH)3(s) [13].…”

“…The TRLS experimental set-up is slightly modified compared to the one already described elsewhere [19,[21][22][23][36][37][38]. It is including a 355 nm tripled neodymium-doped yttrium aluminium garnet (Nd:YAG) laser (Surelite, Continuum) providing ca.…”

“…At pH 13.3, which is the pH value of a CEM-I interstitial cement water [60] -consisting mainly of mixture of KOH and NaOH -, Eu(III) should predominantly be Eu(OH)3(aq) and/or amorphous solid Eu(OH)3(am). If Eu(III) is complexed by HDPs from radiooxidized polyesterurethane, as it is case for the HDPs from a radio-oxidized PVC [38], other molecules than adipate from the ligand pool should be responsible.…”

Interactions between hydro-soluble degradation products from a radio-oxidized polyesterurethane and Eu(III) in contexts of repositories for low and intermediate level radioactive waste

“…Knowledge of interactions between radionuclides and organics contaminants from radio-oxidized polymers -generated during exploitation, maintenance, and dismantling of nuclear fuel cycle facilities [1] -is crucial for assessing the mobility of radionuclides near nuclear waste geological disposals [2][3][4][5][6]. Contaminated polymers should be disposed in primary cemented packages and in cemented over-packages in intermediate level long-lived waste (ILW-LL).…”

“…The resulting products are called hydro-soluble degradation products (HDPs). There is evidence that irradiated polymers induces bacterial nitrate reduction [9], and that HDPs are complexing radionuclides [3][4][5][6][10][11][12][13]. Most of the latter studies were focused on complexation by isosaccharinic acid -a glucose isomer and HDP from non-irradiated cellulose [10][11][12][13].…”