Green Synthesis of Fe ₃ O ₄ ‐ <i>Crataegus tanacetifolia</i> (Lam.) Biochar Magnetic Nanocomposites for Adsorption of Naproxen

Abstract In this study, naproxen (NPX), one of the emerging contaminants was removed by green synthesizing Fe 3 O 4 coated magnetic biochar nanocomposites ( Ct ‐BMNCs) synthesized from Crataegus tanacetifolia Lam. ( Ct ) wastes. The characteristics of Ct ‐BMNCs was examined by x‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x‐ray (EDX), Fourier transform infrared spectroscopy (FTIR), thermogravimetry‐differential thermal analysis (TGA‐DTA), dynamic light scattering (DLS), zetasizer, Brunauer‐Emmett‐Teller (BET) UV–Vis spectroscopy, and pH point of zero charge (pH pzc ). With batch adsorption tests, the effects of pH (4–11), amount of adsorbent (2.5–80 g L −1 ), time, and initial concentration (3.125–200 mg L −1 ), and thermodynamic analysis was performed. Also, kinetic and isotherm models and error functions were used. Accordingly, the pH pzc and average surface charge were 5.68 and +11.7 mV, respectively. Moreover, the reaction was exothermic, and the most suitable models were Pseudo‐second‐order and Freundlich ( R 2 :0.999). Also, q max was 30.12 mgNPX/g Ct ‐BMNCs. Accordingly, Ct‐BMNCs are quite effective in removing NPX.