Modification of a hydrophobic-ligand-containing porous sheet using tri--octylphosphine oxide, and its adsorption/elution of bismuth ions

Tanaka, Ryota*; Ishihara, Ryo*; Miyoshi, Kazuyoshi*; Umeno, Daisuke*; Saito, Kyoichi*; Asai, Shiho; Yamada, Shinsuke*; Hirota, Hideyuki*

Extractants developed for liquid-liquid extraction are useful for the recovery of rare-earth ions. However, the use of such extractants is disadvantageous from environmental and economical viewpoints. In this study, neutral extractant, tri--octylphosphine oxide (TOPO), was combined with a hydrophobic ligand-containing porous polymer sheet. In first, glycidyl methacrylate (GMA) was graft-polymerized onto the porous polyethylene sheet. Second, an octadecane thiol group was introduced into the poly-GMA graft chain. Third, TOPO was deposited on the graft chain via a hydrophobic interaction. Bismuth chloride solution was forced through the pores of the TOPO-modified porous sheet. The equilibrium binding capacity for bismuth was 0.19 mmol/g. Bismuth ions bound to TOPO were quantitatively eluted with 11 M HNO. As TOPO exhibits an affinity interaction with rare-metal ions such as Pd, Pt, and Ru, the TOPO-modified porous sheet prepared in this study will have extensive applications.