Oxidation and adsorption of Sb(III) in wastewater by bifunctional MIL-101(Fe)-Cl loaded sodium alginate hydrogel: Performance and mechanisms

China faces severe antimony pollution due to long-term, high-intensity mining and smelting operations. Long-term exposure to Sb(III) can lead to chronic respiratory problems. Adsorption method is used to remove Sb(III) because of its simplicity, economy and high efficiency. Therefore, a novel MIL-101(Fe)-Cl/SA hydrogel with oxidation-sorption bifunctionality was developed. 1602 cm −1 and 1025 cm −1 correspond to N H and S = O indicate N-chlorosulfonamide is bonded to MIL-101(Fe)-Cl/SA. MIL-101(Fe)-Cl/SA exhibited rough and wrinkled surfaces with numerous irregular particles by SEM. The presence of O (22 %) and Cl (2 %) confirmed the incorporation of N-chlorosulfonamide and SA into MIL-101(Fe)-Cl/SA by EDS and mappings. The adsorption capacities of MIL-101(Fe)-Cl/SA were 86 mg/g at 298 K and 123.21 mg/g at 328 K by Langmuir model. Kinetic and equilibrium correspond to pseudo-second-order and Langmuir model, respectively. Adsorption was spontaneous and endothermic by thermodynamic analysis. MIL-101(Fe)-Cl/SA exhibited enhanced selectivity in solution containing various ions. Moreover, MIL-101(Fe)-Cl/SA demonstrated potential for regeneration and reuse. The removal process primarily involved oxidation, electrostatic interaction, and complexation. In summary, the capability of MIL-101(Fe)-Cl/SA to adsorb and oxidize Sb(III) underscores its promising potential in mitigating the hazards associated with Sb(III).