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

A neutral extractant, tri-n-octylphosphine oxide (TOPO), was used to chemically modify a porous sheet, with a final density of 1.0 mmol/g. First, glycidyl methacrylate (GMA) was graft-polymerized onto a porous polyethylene sheet with an average pore diameter, porosity, and thickness of 1.2 μm, 75%, and 2.0 mm, respectively. 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 (BiCl₃ in 0.15 M HNO₃) 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 HNO₃.