Highly efficient As(v)/Sb(v) removal by magnetic sludge composite: synthesis, characterization, equilibrium, and mechanism studies

Abstract

The development of inexpensive and effective adsorbents for the highly efficient removal of arsenic (As) and antimony (Sb) from water is of great importance for the environment and human health. In the present study, magnetic bio-sludge (MS) containing activated sludge and magnetite (Fe₃O₄) nanoparticles (diameter: 2–25 nm) was investigated as an adsorbent. MS was synthesized by a facile co-precipitation method and characterized using various physicochemical methods. MS featured a macroporous structure with a surface area of 78 m² g⁻¹ and a pore volume of 0.53 cm³ g⁻¹. MS could be readily and easily separated from water using an external magnetic field. Importantly, MS could be applied for the removal of As(V) and Sb(V) contaminants from water. It exhibited high stability, ultrafast adsorption/separation rates, and a large adsorption capacity. Moreover, it achieved near-complete removal of As(V) and Sb(V) in 10 μg L⁻¹ solutions. Its high adsorption performance was almost unaffected by the presence of ion interferents in solution. Thus, the present study demonstrates the potential of MS as an adsorbent for the removal of As(V) and Sb(V) from groundwater to meet environmental and public health standards.