Removal and recovery of Sb(III) from water by CeOx dots modified hematite: An interfacial oxidation route.

Trivalent antimony (Sb(III)) is listed as a priority aquatic contaminant due to its high toxicity. The oxidation of Sb(III) to pentavalent antimony (Sb(V)) and recovery is a desirable process for treatment of Sb-containing wastewater. Given the challenges of low cost and green production, researches on constructing an oxidation route in the absence of homogeneous oxidant for Sb oxidation and recovery are urgent. Herein, cerium oxides (CeOx) dots on hematite material were prepared using low-cost siderite and cerium salt for Sb(III) removal. For the synthesis of material: (1) siderite was converted to hematite by calcination, producing trivalent iron (Fe(III)) for Sb oxidation; (2) the introduced CeOx dots could promote the oxidation and recovery of Sb species. Specifically, the kinetic rate and recovery capacity of CeOx/hematite were up to 0.0941 g mg-1·min-1, 11.45 mg/g, which were higher than those of natural siderite (0.0671 g mg-1·min-1, 1.48 mg/g) and hematite (0.0618 g mg-1·min-1, 0.66 mg/g). More than 50 % of the recovered Sb(III) was oxidized to Sb(V) on the CeOx/hematite surface, indicative of a constructed oxidation route. In addition, CeOx/hematite exhibits a wide range of adaptability, excellent Sb recovery potential in real wastewater, and prospect of large-scale application, making it a promising functional material for Sb recovery and wastewater treatment.