Efficient adsorption of diclofenac sodium from aqueous solutions using magnetic amine-functionalized chitosan

In this study, we prepared a magnetic composite based on amine-functionalized chitosan (aminochitosan; AmCS) and Fe₃O₄ to remove diclofenac sodium (DS) from water. The fabricated AmCS@Fe₃O₄ composite was characterized using Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and thermogravimetric analysis. Furthermore, we investigated the influence of pH, initial DS concentration, and adsorbent dosage on the adsorption of DS. Through thermodynamic analysis, we found that the data corresponded with the Langmuir adsorption isotherm model. The maximum adsorption capacity reached 469.48 mg g^-1, and the adsorption process followed the pseudo-second-order kinetic model. Finally, the AmCS@Fe₃O₄ composite retained good adsorption characteristics after four consecutive cycles, with removal efficiency exceeding 70%. Therefore, the developed adsorbent could be used for efficient adsorptive removal of trace drugs and personal care products from water bodies.