No.11（2016）15.Synthesis of a metal ion adsorbent using banana fibers and its rare metal ions adsorption properties

Tetsuto Kajiyama，Jun Inoue，Toru Yoshino

  The synthesis of metal ion adsorbents using modified banana fibers having a Schiff base as a base material was investigated. In addition, the metal ion adsorption properties of the derived adsorbent were evaluated. Banana fibers (BF)-g-(glycidyl methacrylate)(GMA)(BF-GMA) were synthesized. A Schiff base derivative, 2-2’-{iminobis[ethane-2,1-diylnitrilo(E)methylidine]} bisphenol, was synthesized by the reaction of diethylenetriamine with 5-bromo-salicyialdehyde in methanol. A metal ion adsorbent (BF-GMA(Br)) was synthesized by the reaction of the Schiff base derivative with BF-GMA. Over 90 % of all the metal ions (La³⁺ , Gd³⁺ , Tm³⁺ , Pr³⁺ , Tb³⁺ , Yb³⁺ , Nd³⁺ , Dy³⁺ , Lu³⁺ , Sm³⁺ , Ho³⁺ , Eu³⁺ and Er³⁺ ) from pH 6.0 to 6.6 were adsorbed by the synthesized metal ion adsorbent. In addition, a maximum adsorption rate of almost 100 % at a pH of 3.0 to 4.0 for In³⁺ , and about 95% at a pH 3.9 for Ga³⁺ was demonstrated. For In³⁺ , an adsorption rate of about 15% at a pH of 1.4 to 1.6, and about 25 % at a pH of 1.8 was demonstrated. For Ga³⁺ , almost no adsorption property was demonstrated at a pH of 1.4 to 1.8. Therefore, separation of In³⁺ and Ga³⁺ is possible at a pH of 1.4 to 1.8. These results demonstrate the possibility of using banana fibers as a metal ion adsorbent.

Keywords
Banana fiber, Rare metal ion, Adsorbent

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