Removal of residues of drugs used in cattle farming from aqueous solutions using biochar and biochar/nanoparticle hybrid materials

In this study, biochar was produced from Helichrysum arenarium (Altınotu), a renewable biomass source, and hybridized with Fe₃O₄ nanoparticles to impart magnetic properties to this biochar. The produced biochar and biochar/nanoparticle hybrids were evaluated as adsorbents for the removal of Flunixin meglumine, a drug widely used in cattle farming, from aqueous solutions. Biochar, thanks to its high surface area, porous structure, and functional groups on its surface, has the capacity to effectively adsorb pollutants. The hybrid material offers significant environmental and economic advantages by enabling magnetic recovery. Adsorption experiments were analyzed using kinetic, isotherm, and thermodynamic models, and the obtained data were compared with commercial activated charcoal. Adsorption capacity and binding energies were supported by theoretical calculations, thus revealing interaction mechanisms at the molecular level. The structural, morphological, and surface properties of the materials were characterized in detail using FT-IR, SEM-EDX, TEM, BET, and XRD analyses. Flunixin meglumine concentrations were precisely determined using UV-Vis spectrophotometry. The results demonstrate that Altınotu biochar and magnetic hybrids offer high efficiency and reusability potential for removing pharmaceutical waste from water. These findings provide a significant contribution to the development of low-cost, environmentally friendly, and recyclable adsorbents.