Anion Removal Potential of Complex Metal Oxides Estimated from Their Atomic Scale Structural Properties

Abstract

The main common idea of two conference papers delivered at OMEE-2017 was to demonstrate an importance of the speciation level knowledge in modern adsorption materials science. In order to prove this, two groups of adsorptive materials were used: three samples of Mg-Al-CO3 layered double hydroxides produced by different synthesis methods and ten samples of Fe-Ce oxide-based composites with various ratios of Fe-to-Ce. In both cases of studies, it was not possible to find direct correlation between adsorptive performances of the materials and their structural properties obtained by conventional characterisation techniques. However, anion adsorptive removals of each group of inorganic composites correlated with their structural properties studied on the level of speciation. It was shown that strong anion removal potential of Mg-Al-CO3 layered double hydroxides was associated with richness in speciation of chemical elements (Mg, Al) and interlayer anions (CO32-) as well as with generous hydration. Adsorptive performances of inorganic anion exchangers based on Fe-Ce hydrous oxides were explained by simulation extended X-ray absorption fine structures simulation. The best anion removers were found to be those Fe/Ce oxide-based composites whose Fe outer shells were formed from backscattering oscillations from both O and Fe atoms.