Recovery of p.t-CEtGeO Using Chelating Porous Membranes Prepared with Various Compositions of Dioxane/Water Solvent

• Published in: Journal of Ion Exchange Vol. 18; no. 2; pp. 68 - 74
• Main Authors: MOCHIZUKI, Takena, SAITO, Kyoichi, SATO, Katsuyuki, AKIBA, Mitsuo, SUGO, Takanobu
• Format: Journal Article
• Language: English
• Published: Japan Society of Ion Exchange 2007
• Subjects: adsorption; chelating porous membrane; hollow fiber; p.t-CEtGeO; solvent composition
• ISSN: 0915-860X; 1884-3360
• DOI: 10.5182/jaie.18.68

An epoxy-group-containing monomer, glycidyl methacrylate (GMA), was grafted onto the pore surface of a porous hollow-fiber membrane made of polyethylene by radiation-induced graft polymerization. Two reagents for the introduction of chelating groups capable of capturing poly-trans- [ (2-carboxyethyl) germanium sesquioxide] (p.t-CEtGeO) were reacted with the epoxy group of the poly-GMA chain: 2-nitrilopropanol-2-nitriloisopropanol (PAIPA) and N, N2-hydroxy-isopropyl-2, 3-dihydroxy-n-propylamine (THDPA) . The reagents were dissolved in a mixture of dioxane and water at various dioxane volume fractions, defined by dividing the dioxane volume by the total volume. The equilibrium binding capacity (EBC) for p.t-CEtGeO of the two chelating porous hollow-fiber membranes was evaluated in a permeation mode. The THDPA-type hollow fiber prepared with a dioxane volume fraction of 0.4 exhibited a maximum EBC of 0.48mmol/g which was equivalent to 3.9-fold compared to the THDPA-type hollow fiber prepared with dioxane-free solvent. The permeation of p.t-CEtGeO solution through the pores of the chelating porous hollowfiber membrane minimized the diffusional path of p.t-CEtGeO in the pore interior to the chelating group of the polymer chain grafted onto the pore surface, resulting in a high-speed collection of p.t-CEtGeO.