Properties of iron-functionalized organoclays. Consequences for pertechnetate sequestration

Nuclear waste repository designs require backfill materials capable of immobilizing contaminants, including high mobility pertechnetate (TcO4-). Bentonite backfill can be functionalized with organic or inorganic species to optimize the clay's retention capacity for TcO4-. The current work examines the physicochemical properties of organoclays that were functionalized with alkylammonium cations of different sizes and iron. The organoclays were characterized, and the physicochemical characteristics were correlated with the extent of TcO4-; removal. The results show that the clay zeta potential and carbon content are valuable indicators for predicting the organoclay's ability to sequester TcO4-; from aqueous solution. Furthermore, the Fe functionalization improves TcO4-; removal.