Mesoporous Zirconium Titanium Oxides. Part 2: Synthesis, Porosity, and Adsorption Properties of Beads

Abstract

Mesoporous zirconium titanium mixed-oxide beads having disordered wormhole textures and mole 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 m2/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.

Ultralight Multiwalled Carbon Nanotube Aerogel

“…The MWCNT aerogels have potential applications as sorption-based chemoresistance vapor sensors since their hierarchical porous structures not only provide high surface area but also facilitate the analyte diffusion in the aerogel. , The response of the MWCNT aerogels resistance to chloroform vapor was investigated (Supporting Information). As shown in Figure a, the resistance of the MWCNT aerogels increases to a saturated value in 0.5 s upon exposure to the vapor, and completely recovers in 0.5 s upon exposure to air even at very low vapor concentration.…”

Inorganic molecular imprinted titanium dioxide photocatalyst: synthesis, characterization and its application for efficient and selective degradation of phthalate esters

“…Because one DEP molecule is adsorbed on the surface via its interaction with two Lewis acid sites and the initial amount of DEP is in a great excess relative to its adsorption on the photocatalyst, it is reasonable that the adsorption of DEP on the photocatalyst behaves like a pseudosecond-order reaction in kinetics. [34][35][36] We may assume: (i) there is a monolayer of target DEP on the surface of the catalyst; (ii) the energy of sorption for each DEP is the same and is not dependent on the surface coverage; (iii) DEP is only adsorbed on localized sites and the adsorbed DEP molecules do not interact with each other. Thus, the rate of DEP adsorption can be expressed with eqn (2),…”

Effective Am(iii)/Eu(iii) separations using 2,6-bis(1,2,4-triazin-3-yl)pyridine (BTP) functionalised titania particles and hierarchically porous beads

“…11 The bead morphology is desirable as it allows close packing in chromatographic columns with minimal clogging and high ease of handling. 12 To prepare the beads, precursor solutions (containing TiCl 4 , ethanol, F127 and water) were infiltrated into macroporous polyacrylonitrile (PAN) beads and evaporated under controlled temperature and humidity. The PAN and F127 templates were then removed by thermal treatment to afford millimetre sized, monodisperse, spherical, hierarchically porous beads.…”