Terpyridine-based silica supports prepared by ring-opening metathesis polymerization for the selective extraction of noble metals.
The synthesis of a terpyridine-based sorbent for solid-phase extraction (SPE) of noble metal ions is described. For this purpose, 4'-(norborn-2-en-5-ylmethylenoxy)terpyridine was copolymerized with norborn-2-ene via Mo(N-2,6-i-Pr2-C6H3)(=CHCMe2Ph) (OC(CH3)(CF3)2)2-catalyzed ring-opening metathesis polymerization (ROMP) to give a poly(norbornene900(-b-4'-(norborn-2-en-5-ylmethylenoxy)terpyridine60) block-copolymer. This block-copolymer was used for the preparation of polymer-coated silica 60 (4.8 wt.% coating), which was investigated for its extraction capabilities for Cr(III), Mn(II), Re(II), Fe(III), Ru(III), Co(II), Rh(III), Ir(III), Ni(II), Pd(II), Pt(II), Cu(II), Ag(I), Au(III), Zn(II), Cd(II) and Hg(II), at different pH. Under competitive conditions and at pH < 0.6, the selectivity order was Pd approximately = Ag approximately = Au approximately = Pt > Re > Ir > Rh > Ru > Fe > Cr approximately = Mn approximately = Cd approximately = Zn. Enhanced selectivity was observed at pH = 3.5, the order was Au > Hg > Pd approximately = Ag > Rh > Pt > Ir approximately = Re > Cu > Co approximately = Zn approximately = Cd approximately = Ni > Cr > Mn. The maximum metal loading that was achieved under non-competitive conditions was > 6 mg/g for Au(III), Hg(II), Pd(II) and Ag(I). Even under competitive conditions, loadings of > 6 mg/g were realized for Au(III) and Hg(II). Quantitative recoveries > 97% were observed for all metals in case loading was stopped before reaching the point of breakthrough.
Institut für Analytische Chemie und Radiochemie, Universität Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria.
Ines
I
Glatz
Monika
M
Mayr
Richard
R
Hoogenboom
Ulrich S
US
Schubert
Michael R
MR
Buchmeiser
D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
D008670:Metals; D011108:Polymers; D011725:Pyridines; D012822:Silicon Dioxide; C023666:pyridine