Cesium adsorption ability and stability of metal hexacyanoferrates irradiated with -rays

線照射したヘキサシアノ鉄酸金属錯体のセシウム吸着性能と安定性

有阪 真 ; 渡邉 雅之   ; 石崎 学*; 栗原 正人*; Chen, R.*; 田中 寿*

Arisaka, Makoto; Watanabe, Masayuki; Ishizaki, Manabu*; Kurihara, Masato*; Chen, R.*; Tanaka, Hisashi*

不溶性フェロシアン化物は、溶液中のセシウム(Cs)を選択的に吸着する材料としてよく知られている。本研究では、不溶性フェロシアン化物類縁体であるヘキサシアノ鉄酸金属錯体塩(MHCF: M=Fe, Cu, Ni)から成るナノ粒子吸着材を対象に、線照射に対する吸着材の安定性と線照射がCs吸着能に与える影響について調べた。50300kGyの吸収線量の範囲において、線照射後の硝酸中にFe, Cu、又はNiがわずかながら検出され、吸収線量の増加に伴いそれらの濃度が増加することから、放射線分解の進行が確認された。その際、MHCF中の炭素, 窒素, 水素の組成比は維持されていた。一方、CsのMHCFへの分配係数は充分に大きな値を示し、明確な吸収線量依存性が見られなかったことから、長期の使用に耐え得ると考えられる。

The influence of irradiation with -rays to metal hexacyanoferrate (MHCF: M = Fe, Cu or Ni), which is known as an adsorbent for selective adsorption of cesium (Cs) ion in solution, on Cs adsorption ability and stability was investigated in HNO solutions. Under the adsorbed dose conditions (50-300 kGy), it was found that the MHCF is fully stable although the radiolytic decomposition of MHCF was slightly observed with an increase of the total adsorbed dose, which was confirmed by an increment of Fe, Cu or Ni concentration in HNO solution after the irradiation. The weight percent of the metal in the solution to initial weight of MHCF was less than unity. Moreover, no change in composition of carbon, hydrogen and nitrogen in MHCF was observed. On the other hand, the distribution coefficients of Cs to the irradiated MHCF were independent of the total adsorbed dose. This indicates that the Cs adsorption ability was maintained under -ray irradiation.