Efficient removal of amoxicillin and paracetamol from aqueous solutions using magnetic activated carbon

Activated carbon (AC)/CoFe₂O₄ nanocomposites, MAC-1 and MAC-2, were prepared by a simple pyrolytic method using a mixture of iron(III)/cobalt(II) benzoates and iron(III)/cobalt(II) oxalates, respectively, and were used as efficient adsorbents for the removal of amoxicillin (AMX) and paracetamol (PCT) of aqueous effluents. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The sizes of cobalt ferrite nanoparticles formed from benzoates of iron(III)/cobalt(II) and oxalates of iron(III)/cobalt(II) precursors were in the ranges of 5–80 and 6–27 nm, respectively. The saturation magnetization (M_s), remanence (M_r) and coercivity (H_c) of the MAC-2 nanocomposites were found to be 3.07 emu g⁻¹, 1.36 emu g⁻¹ and 762.49 Oe; for MAC-1, they were 0.2989 emu g⁻¹, 0.0466 emu g⁻¹ and 456.82 Oe. The adsorption kinetics and isotherm studies were investigated, and the results showed that the as-prepared nanocomposites MAC-1 and MAC-2 could be utilized as an efficient, magnetically separable adsorbent for environmental cleanup. The maximum sorption capacities obtained were 280.9 and 444.2 mg g⁻¹ of AMX for MAC-1 and MAC-2, respectively, and 215.1 and 399.9 mg g⁻¹ of PCT using MAC-1 and MAC-2, respectively. Both adsorbents were successfully used for simulated hospital effluents, removing at least 93.00 and 96.77% for MAC-1 and MAC-2, respectively, of a mixture of nine pharmaceuticals with high concentrations of sugars, organic components and saline concentrations.