The remediation of technetium-99 (99Tc) at contaminated sites remains a major challenge, as Tc high solubility and anionic nature under oxic conditions lead to high contaminant mobility. Hydrotalcite, a form of anionic clay, can strongly retain anions, especially upon mineral calcination. However, naturally occurring humic acids can also sorb onto hydrotalcite, therefore competing with TcO4? for sorption sites. This work explores the ability of hydrotalcite to retain TcO4? in presence of humic substances to evaluate the efficacy of hydrotalcite for Tc remediation in natural environment. Results show that calcined hydrotalcite can immobilize TcO4?, while the presence of 23 ppm humic acids has little influence on TcO4? uptake. However, additional monatomic and polyatomic anions in solution can compete with TcO4? for sorption sites on hydrotalcite.
