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.