Fabrication of Porous Zirconia Microspheres as an Efficient Adsorbent for Removal and Recovery of Trace Se(IV) and Te(IV)

Porous 3D zirconia (ZrO2) microspheres were successfully fabricated using urea as soft templates. The obtained ZrO2 exhibits strong enrichment ability for SeO32– and TeO32– owing to its high chemical affinities to the targets and possesses excellent acid and alkali resistance. A new enrichment method which uses the as-synthesized ZrO2 as an adsorbent for high-efficiency recovery of selenium and tellurium has been developed. The removal efficiencies of SeO32– and TeO32– could reach 99.48% and 98.71%, respectively. Moreover, an interesting phenomenon was found; namely, the ZrO2 can be used to effectively remove TeO32– from the SeO32– and TeO32– mixture solution containing phosphate. In order to understand the adsorption process and mechanism, the kinetics and thermodynamics have been investigated. The sorption data fitted well with the Langmuir model, and the kinetic experimental data properly correlated with the pseudo-second-order kinetic model. The possible mechanisms between targets and the ZrO2 microspheres were proposed.