Fine fibrous amidoxime adsorbent synthesized by grafting and uranium adsorption-elution cyclic test with seawater

グラフト重合法により作製したアミドキシム吸着材の海水を用いたウラン吸着-離耐久性試験

瀬古 典明; 片貝 秋雄; 玉田 正男; 須郷 高信*; 吉井 文男

Seko, Noriaki; Katakai, Akio; Tamada, Masao; Sugo, Takanobu*; Yoshii, Fumio

繊維状のアミドキシム吸着材を放射線グラフト重合法により作製した。得られた吸着材を用いて海水中に溶存するウランの吸脱着試験を繰り返して行った。溶離剤として塩酸を用いて吸脱着を繰り返し行うと使用回数5回でウランの吸着性能は失われた。しかし、溶離後の吸着材にアルカリ処理を施すことで25%程度その減少を抑えることができた。さらに、溶離剤に酒石酸などの有機酸を用いることで初期吸着量の80%程度ではあるものの劣化の程度を抑制することが可能になった。

Fibrous amidoxime adsorbents were prepared by radiation-induced co-grafting of acrylonitrile (AN) and methacrylic acid (MAA) and subsequent amidoximation. Adsorption of uranium in seawater was evaluated by pumping seawater into the adsorbent column. The best monomer ratio of AN and MAA was 7:3 for continual usage of uranium adsorption. Though hydrochloric acid is an effective eluting agent for the metals adsorbed on the adsorbent, amidoxime groups were simultaneously damaged after five cycles of adsorption-desorption. This deterioration was reduced by an alkaline treatment of the adsorbents after each elution. Furthermore, various organic acids were examined as elution agents. It was found that the 80% of adsorption activity was still maintained after five cycles of adsorption-desorption when tartaric acid was used for eluting agent.