Facile Synthesis of Sulfur-Modified FeMnO₃-FeSO₃ as a High-Affinity Adsorbent for Efficient Antimony Removal

Nowadays, antimony (Sb) pollution resulting from industrial activities has evolved into a critical global environmental issue, posing severe threats to aquatic ecosystems and human health. Notably, hydroxyl-dominated adsorbents are predominantly adopted in practical engineering for Sb remediation due to their facile preparation and low cost, but suffer from inherent drawbacks of unsatisfactory adsorption efficiency and poor selectivity, which severely limits their application in complex wastewater matrices-especially in acidic mine tunnel seepage water from non-ferrous metal mining areas, where the urgent demand for efficient Sb removal remains unmet. To address these challenges and cater to the practical treatment needs of acidic mine tunnel seepage water, a novel FeMnO₃-FeSO₃ composite was fabricated via a liquid-phase controlled solvothermal strategy using CS₂ as the sulfur source, where the material structure was regulated by adjusting the water–ethanol ratio, enabling sulfur to stably grow as FeSO₃ crystals on the FeMnO₃ surface. The composite exhibited enhanced Sb adsorption capacity, with maximum adsorption capacities for Sb(III) and Sb(V) reaching 48.2 mg·g⁻1 and 46.8 mg·g⁻1 (at an initial Sb concentration of 5.0 mg·L⁻1 and pH 4.0), respectively. It also showed superior Sb selectivity against high-concentration coexisting ions, excellent stability in practical smelting wastewater, and surface sulfur modification effectively inhibited metal ion leaching. Systematic characterizations revealed that the stable FeSO₃-modified surface induced synergistic interfacial electrostatic and high-affinity complexation effects, accounting for the superior performance. This work provides a feasible approach for designing high-performance sulfur-modified adsorbents, offering promising technical support for Sb-contaminated wastewater remediation, particularly for the challenging treatment of acidic mine tunnel seepage water.