화학공학소재연구정보센터
Langmuir, Vol.24, No.21, 12323-12330, 2008
Mesoporous Zirconium Titanium Oxides. Part 2: Synthesis, Porosity, and Adsorption Properties of Beads
Mesoporous zirconium titanium mixed-oxide beads having disordered wormhole textures and mote fractions of Zr (x) ranging from x = 0.25 to 0.67 have been prepared. The bead preparation method combined the forced hydrolysis of mixtures of zirconium-titanium alkoxides in the presence of long-chain carboxylates with external gelation. Uniformly sized beads could be produced in the size range 0.5-1.1 mm by varying the droplet size and viscosity of the mixed-oxide sol, thus making them suitable for large-scale column chromatographic applications. The beads exhibited narrow pore size distributions with similar mean pore diameters of around 3.7 nm. The specific surface areas of the beads were linked to the Zr mole fraction in the precursor solution and were generally greater than 350 m(2)/g for x = 0.5. A combination of scanning transmission electron microscopy and X-ray absorption fine structure analysis indicated that the pore walls of the beads were composed of atomically dispersed Zr and Ti to form a continuous network of Zr-O-Ti bonds. Mass transport in the beads was evaluated by monitoring the kinetics of vanadate and vanadyl adsorption at pH 10.5 and 0.87, respectively.