Enhanced removal of Sb(III) from aqueous solutions using Fe-Mn binary oxide-modified attapulgite

An affordable, environmentally friendly, simple adsorbent for Sb(III) removal from aqueous solutions was prepared using attapulgite (ATP) as the matrix, and FeSO4 and KMnO4 as metal precursors, through an in situ precipitation approach. The morphology, pore structure, and surface chemical properties of the material were analyzed using various characterization techniques. The results indicate that the iron-manganese bimetallic-modified acid-activated ATP (FeMn-HATP) surface is loaded with relatively uniformly distributed iron and manganese components, and its specific surface area and pore structure differ significantly from the original ATP. These changes promote pollutant molecule diffusion and contact. In batch adsorption experiments, FeMn-HATP achieved good Sb(III) removal performance and remained relatively stable within a pH range of 410. The material maintained a relatively stable adsorption capacity even in the presence of high concentrations of other anions. Adsorption of Sb(III) by the modified ATP better conforms to both Elovich kinetic and Langmuir isotherm models, with a theoretical maximum adsorption capacity of 102.79 mg/g at 318.15 K. Fixed-bed cycling experiments demonstrated that FeMn-HATP retained significant adsorption capacity after five NaOH regenerations, with a dynamic adsorption capacity of 14.68 mg/g and a regeneration efficiency of 68.16%. Overall, FeMn-HATP exhibits good potential for Sb(III) removal with a degree of reusability, indicating promise for the treatment of antimony-containing wastewater