Synergistic adsorption and oxidation of trivalent antimony from groundwater using biochar supported magnesium ferrite: Performances and mechanisms

Antimony (Sb) pollution is considered an environmental problem, since Sb is toxic and carcinogenic to humans. Here, a novel biochar supported magnesium ferrite (BC@MF) was adopted for Sb(III) removal from groundwater. The maximum adsorption capacity was 77.44 mg g(-1). Together with characterization, batch experiments, ki-netics, isotherms, and thermodynamic analyses suggested that inner-sphere complexation, H-bonding, and electrostatic interactions were the primary mechanisms. C-C/C--C, C-O, and O-C--O groups and Fe/Mg oxides might have acted as adsorption sites. The adsorbed Sb(III) was oxidized to Sb(V). The generation of reactive oxygen species, iron redox reaction, and oxidizing functional groups all contributed to Sb(III) oxidation. Furthermore, the fixed-bed column system demonstrated a satisfactory Sb removal performance; BC@MF could treat similar to 6060 BV of simulated Sb-polluted groundwater. This research provides a promising approach to suffi-ciently remove Sb(III) from contaminated groundwater, providing new insights for the development of inno-vative strategies for heavy metal removal.

Automated summary

In this study, a novel biochar supported magnesium ferrite (BC@MF) was used for the removal of Sb(III) from groundwater. The maximum adsorption capacity was found to be 77.44 mg g(-1). Inner-sphere complexation, H-bonding, and electrostatic interactions were identified as the primary mechanisms, with potential adsorption sites including C-C/C--C, C-O, and O-C--O groups, as well as Fe/Mg oxides. The adsorbed Sb(III) was oxidized to Sb(V), and the fixed-bed column system demonstrated efficient Sb removal performance.