The mechanism of antimony(III) removal and its reactions on the surfaces of Fe–Mn Binary Oxide

Antimony is a regulated pollutant to be well controlled. This study compared the removal capability and mechanisms involved in the removal of Sb(III) by Fe–Mn Binary Oxide (FMBO), ferric hydroxide (FeOOH), and manganese dioxide (MnO2). FMBO shows a maximum Sb removal capacity of 1.76 mmol/g and was much higher than that of both FeOOH (0.83 mmol/g) and MnO2 (0.81 mmol/g). Characterization techniques of FTIR and XPS indicated the different variation trends of functional groups, surface elemental composition, and chemical valence of Fe, Mn, and Sb after the adsorption of Sb(III) on these three adsorbents. As for FMBO, results indicated that the manganese oxide dominated in oxidation of Sb(III) to Sb(V) whereas the iron oxide adsorbed the Sb(III) and Sb(V). The oxidation and sorption mechanism was proposed to involve in the removal of Sb(III) by FMBO. FMBO may be promisingly used to remove Sb from drinking water and wastewater.

Graphical abstractOxidation and sorption mechanism could well explain the higher Sb(III) uptake by FMBO than FeOOH and MnO2.Figure optionsDownload full-size imageDownload high-quality image (93 K)Download as PowerPoint slideHighlights► FMBO is an effective novel adsorbent to remove Sb(III) and exhibits much higher removal capacity than FeOOH and MnO2. ► Oxidation and sorption mechanism could well explain the higher Sb(III) uptake by FMBO than MnO2 and FeOOH. ► The manganese oxide within FMBO dominates the oxidation of Sb(III) to Sb(V), whereas the iron oxide acts as the adsorption sites.