Sorption of U(VI) on the 4-mercaptopyridine self-assembled monolayer

自己組織化されたピリジンへのU(VI)の吸着

南川 卓也 ; 鈴木 義規; 尾崎 卓郎; Francis, A. J.; 大貫 敏彦

Nankawa, Takuya; Suzuki, Yoshinori; Ozaki, Takuo; Francis, A. J.; Onuki, Toshihiko

金薄膜上に形成したピリジン自己組織化単分子へのU(VI)の吸着を実験により検討した。pH4のU(VI)溶液にピリジン自己組織化単分子を付加した金電極を作用極として電位-電流曲線を測定し、U(VI)の還元電流を検知できたことから、ピリジン自己組織化単分子へのU(VI)の吸着が確認された。酢酸及びシュウ酸溶液を用いてU(VI)の吸着を電位-電流曲線により調べた結果、U(VI)とピリジン自己組織化単分子との錯形成能は、酢酸とシュウ酸の中間にあることがわかった。

Sorption of U(VI) on the 4-mercaptopyridine self-assembled-monolayer (4-PyS-SAM) on Au(111) was studied by cyclic voltammetry. Cyclic voltammograms (CV) of the 4-PyS-SAM working electrode was obtained by contact with 1 mM UO(NO) solution, 1 mM UO(NO) and 50 mM acetic acid solution, or 1 mM UO(NO) and 50 mM oxalic acid solution for 6 h at pH 4. Reduction current of uranium(VI) to U(V) was detected in the CV. The CV of the U(VI) associated 4-PyS-SAM after transporting to U(VI) free 0.1 M NaClO4 solution showed that the reduction current was detected in the cases of UO(NO) and U(VI)-acetate, but not in the case of U(VI)-oxalate solutions, indicating that U(VI) was adsorbed on the 4-PyS-SAM from the UO(NO) and U(VI)-acetate solutions, but not from U(VI)-oxalate solution. These results suggests that stability of U(VI)-4-PyS-SAM is not so high that U(VI)-4-PyS-SAM cannot be formed in the presence of 50 mM oxalate.