Adsorptive removal of arsenic from water by iron-loaded carbonized spent bleaching earth (Fe-SBE/C) composite

Arsenic contamination in groundwater is a pressing issue in many developing regions, demanding cost-effective and sustainable treatment solutions. This study investigates the use of spent bleaching earth (SBE), an industrial byproduct, as a precursor for synthesizing a magnetic adsorbent (Fe-SBE/C) <i>via</i> calcination followed by iron co-precipitation. The Fe-SBE/C composite exhibited notable adsorption capacities for both arsenite (As(III)) and arsenate (As(V)), achieving maximum removal efficiencies of 76.7% at pH 10.0 and 94.1% at pH 3.0, respectively. Adsorption kinetics adhered to elovich and intraparticle diffusion models, indicating a dual mechanism involving adsorption boundary layer control and chemisorption, while isotherm studies revealed Langmuir model compatibility, with maximum capacities of 202.609 μg g⁻¹ for As(III) and 187.611 μg g⁻¹ for As(V). Further thermodynamic and activation energy analyses reinforced chemisorption as the dominant process, which supported the presence of iron oxide (Fe²⁺/Fe³⁺) dan surface functional groups critical to arsenic removal by XRD, FTIR, SEM-EDX, and XPS. Regeneration studies demonstrated reusability of Fe-SBE/C over multiple cycles. These results support Fe-SBE/C as an efficient, low-cost adsorbent for arsenic removal, especially in resource-limited areas. These results underscore the potential of Fe-SBE/C as a sustainable and low-cost adsorbent, particularly due to its ability to transform industrial waste into value-added materials for arsenic removal.