Sorption-desorption of antimony species onto calcined hydrotalcite: Surface structure and control of competitive anions

摘要

Graphical abstractDisplay OmittedHighlights•Anion competitive sorption for Sb species on calcined hydrotalcite was proposed.•Sb(III) and Sb(V) sorption was affected by sulfate and phosphate, respectively.•Antimony species were mainly sorbed onto HTC by specific interactions.•EDXRF spectra indicated higher Sb(III) retention onto the sorbent.•A mobilization factor was proposed to estimate desorption extent from hysteresis.AbstractCalcined hydrotalcite can be applied to remove anionic contaminants from aqueous systems such as antimony species due to its great anion exchange capacity and high surface area. Hence, this study evaluated antimonite and antimonate sorption–desorption processes onto calcined hydrotalcite in the presence of nitrate, sulfate and phosphate. Sorption and desorption experiments of antimonite and antimonate were carried out in batch equilibrium and the post-sorption solids were analyzed by X-ray fluorescence (EDXRF). Sorption data were better fitted by dual-mode Langmuir–Freundlich model (R2−1. The competing anions strongly affected the antimony sorption. EDXRF analysis and mathematical modelling showed that sulfate and phosphate presented higher effect on antimonite and antimonate sorption, respectively. High values for sorption efficiency (SE=99%) and sorption capacity were attributed to the sorbent small particles and the large surface area. Positive hysteresis indexes and low mobilization factors (MF