Adsorption of uranium(VI) on silica particles modified with protein

Kozai, Naofumi   ; Suzuki, Yoshinori; Nankawa, Takuya ; Sakamoto, Fuminori  ; Onuki, Toshihiko; Francis, A. J.

One of the biomolecules at the cell surface of bacteria to bind uranium is protein. To clarify adsorption mechanism of uranium on protein, this study investigated the adsorption of uranium (VI) on protein by use of silica particles modified with a cell surface protein, protein A. Unmodified silica particles (Si-OH) and the silica particles on which one kind of the following functional groups, -COOH, -NH, and -OPOH, was fixed were also used as reference. The adsorption pf uranyl ions on the silica particles modified with amino group and phosphoric group are the greatest. The sorption behavior of uranyl ions on silica particles modified with protein A was similar to those on the silica particles modified with amino group and phosphoric group. However, because the content of phosphoric group in protein A is low, amino group is thought to be the major adsorption site of uranyl ions on the protein A-modified particles.