Ce-Fe-modified zeolite-rich tuff to remove Ba²⁺-like ²²⁶Ra²⁺ in presence of As(V) and F^- from aqueous media as pollutants of drinking water

The sorption behavior of the Ba²⁺-like ²²⁶Ra²⁺ in the presence of H₂AsO₄^-/HAsO₄^2- and F^- from aqueous media using Ce-Fe-modified zeolite-rich tuff was investigated in this work. The Na-modified zeolite-rich tuff was also considered for comparison purposes. The zeolite-rich tuff collected from Wyoming (US) was in contact with NaCl and CeCl₃-FeCl₃ solutions to obtain the Na- and Ce-Fe-modified zeolite-rich tuffs (ZUSNa and ZUSCeFe). These zeolites were characterized by scanning electron microscopy and X-ray diffraction. The BET-specific surface and the points of zero charge were determined as well as the content of Na, Ce and Fe by neutron activation analysis. The textural characteristics and the point of zero charge were changed by the presence of Ce and Fe species in the zeolitic network. A linear model described the Ba²⁺-like ²²⁶Ra²⁺ sorption isotherms and the distribution coefficients (K_d) varied with respect to the metallic species present in the zeolitic material. The As(V) oxianionic chemical species and F^- affected this parameter when the Ba²⁺-like ²²⁶Ra²⁺-As(V)-F^- solutions were in contact with ZUSCeFe. The H₂AsO₄^-/HAsO₄^2- and F^- were adsorbed by ZUSCeFe in the same amount, independent of the concentration of Ba²⁺-like ²²⁶Ra²⁺ in the initial solution.