Application of magnetic activated carbon coated with CuS nanoparticles as a new adsorbent for the removal of tetracycline antibiotic from aqueous solutions (isotherm, kinetic and thermodynamic study)

In this study, we investigated the influence of a novel magnetic activated carbon (MAC) nanocomposite coated with CuS (MAC/CuS) on the successful removal of tetracycline (TC) molecules from aqueous solutions via adsorption. The physical and structural properties of the synthesized sorbent were determined using the field-emission scanning electron microscopy, Brunauer-Emmett-Teller, X-ray diffraction, Fourier-transform infrared spectroscopy, and vibrating-sample magnetometer techniques. Equilibrium isotherms and adsorption kinetics were studied. Additionally, the effects of pH (3, 5, 7, and 9), TC concentration (5-100 mg/L), MAC/CuS dosage (0.025-2.5 g), temperature (5C, 10C, 20C, 40C, and 50C), and contact time (from inception to 200 min) were extensively examined. Our results revealed that the highest TC removal percentage was approximately 70% under optimal conditions (pH = 9, contact time = 200 min, nanocomposite dosage = 2 g/L, and temperature = 20C). Modelling of the experimental data using isothermal models indicated that the TC adsorption process followed the Temkin model. Thermodynamic analyses revealed that the adsorption process was spontaneous and exothermic. A kinetic study demonstrated that the pseudo-second-order kinetic model was best for describing TC adsorption. This work presents a magnetic activated carbon nanocomposite coated with CuS as a high-efficiency adsorbent for the remediation of wastewater loaded with TC.