Uptake of Ra-226 in cementitious systems: A complementary solution chemistry and atomistic simulation study

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F18%3A10384586" target="_blank" >RIV/00216208:11320/18:10384586 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.apgeochem.2018.06.015" target="_blank" >https://doi.org/10.1016/j.apgeochem.2018.06.015</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.apgeochem.2018.06.015" target="_blank" >10.1016/j.apgeochem.2018.06.015</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Uptake of Ra-226 in cementitious systems: A complementary solution chemistry and atomistic simulation study

Popis výsledku v původním jazyce

The uptake of Ra-226 to various cement hydration phases such as calcium-silicate-hydrates (C-S-H), ettringite (AFt) and monosulfate (AFm) as well as hardened cement pastes (HCP) made from ordinary Portland cement and low pH cement, respectively, was studied in batch-type sorption experiments under anoxic conditions. Besides sorption kinetics, the effects of solution composition and solid to liquid ratios were analyzed. Uptake kinetics were generally fast, leading to sorption equilibrium in less than 30 days. In particular, a strong retention of Ra-226 by C-S-H phases was observed with a dependency of distribution coefficients on the Ca/Si - ratio of the C-S-H and the alkali content in solution. Atomistic simulation provided evidence that, in addition to Ra sorption on surface sites, the uptake of Ra due to exchange for Ca in the C-S-H interlayer space is a plausible uptake mechanism, in particular at low Ca/Si-ratios. Experiments performed on HCP revealed a correlation between sorption distribution coefficients of Ra-226 and C-S-H content and composition. Experiments on C-S-H alteration showed that upon carbonation previously bound Ra is predominantly released into the pore solution, although some Ra can be retained by newly formed calcite.

Název v anglickém jazyce

Uptake of Ra-226 in cementitious systems: A complementary solution chemistry and atomistic simulation study

Popis výsledku anglicky

The uptake of Ra-226 to various cement hydration phases such as calcium-silicate-hydrates (C-S-H), ettringite (AFt) and monosulfate (AFm) as well as hardened cement pastes (HCP) made from ordinary Portland cement and low pH cement, respectively, was studied in batch-type sorption experiments under anoxic conditions. Besides sorption kinetics, the effects of solution composition and solid to liquid ratios were analyzed. Uptake kinetics were generally fast, leading to sorption equilibrium in less than 30 days. In particular, a strong retention of Ra-226 by C-S-H phases was observed with a dependency of distribution coefficients on the Ca/Si - ratio of the C-S-H and the alkali content in solution. Atomistic simulation provided evidence that, in addition to Ra sorption on surface sites, the uptake of Ra due to exchange for Ca in the C-S-H interlayer space is a plausible uptake mechanism, in particular at low Ca/Si-ratios. Experiments performed on HCP revealed a correlation between sorption distribution coefficients of Ra-226 and C-S-H content and composition. Experiments on C-S-H alteration showed that upon carbonation previously bound Ra is predominantly released into the pore solution, although some Ra can be retained by newly formed calcite.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Applied Geochemistry

ISSN

0883-2927

e-ISSN

—

Svazek periodika

96

Číslo periodika v rámci svazku

29 June 2018

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

204-216

Kód UT WoS článku

000442098100019

EID výsledku v databázi Scopus

2-s2.0-85049725051