Synthesis of hierarchical mesoporous cerium titanate brannerite and uranyl adsorption properties at pH 3.8.

Abstract

Cerium titanates possessing brannerite structure are produced by employing soft and hard templates via sol-gel processing. Powders synthesized with various hard template sizes and template to brannerite weight ratios are composed of nanoscale 'building blocks' with size ∼20-30 nm and characterized on macro-, nano- and atomic scales. These polycrystalline oxide powders exhibit specific surface area up to ∼100 m2 g-1, pore volume ∼0.4 cm3 g-1, and uranyl adsorption capacity ∼0.221 mmol (53 mg) U per gram powder. Remarkably, the materials possess significant proportion of mesopores with 5-50 nm pores representing 84-98% of total pore volume, which facilitate fast accessibility of the adsorbate to the internal surfaces of the adsorbent with adsorbed uranyl reaching over 70% of the full capacity within 15 min of contact. These mesoporous cerium titanate brannerites synthesized by the soft chemistry route are highly homogenous, stable at least in 2 mol L-1 acidic or basic solution, and may attract attention for other applications like catalysis at high temperature.