Preparation And Modification Of Magnetic Carbon Materials And Its Adsorption Properties Of Antibiotics

Magnetic carbon nanocomposite is a new kind of composite materials with core-shell structure. And it has marked advantage over traditional carbon materials because of its unique magnetic properties. The Fe₃O₄/C composite was synthesized using a one-step hydrothermal method with ferric nitrate, glucose and urea as raw materials. The products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, vibrating-sample magnetometry, scanning electron microscopy, transmission electron microscopy, and N2 adsorption/desorption isotherm measurements. Besides, we have studied the effect of reaction temperature, time and the amount of glucose on morphology of composites. The results indicated that Fe₃O₄/C composite had an average size of 140 nm. The saturation magnetization of the product was ⁴6.12 emu/g. The product surface had a variety of functional groups that were prone to adsorption of CIP. The Brunauer–Emmett–Teller?BET? surface area was 17.743 m²/g and the pore size distribution ranged within 20–30 nm. The conditions of hydrothermal reaction influenced the particle size and morphology of composites markedly.Thermal treatment was adopted to modify the surface properties of the composites. The specific surface increased from 17.743 to 79.017 m²/g. For the ciprofloxacin adsorption on the adsorbent, the Langmuir model was suitable for describing the adsorption process. The pseudo-second-order kinetic model fitted the experimental kinetic curve well. Thus, physical adsorption is the main route adsorption on the adsorbent. The maximum adsorption capacity of ciprofloxacin was 90.1 mg/g. Adsorption thermodynamic studies indicated that adsorption is mainly spontaneous endothermic adsorption. A mixture of 10 mL 3% NaOH solution and 50 mL methanol was applied to regenerate the used adsorbent. The results suggested that the removal rate of ciprofloxacin decreased from 98.2% to 61.2% after five rounds of recycling. The adsorbent could be recycled.For sulfanilamide adsorption on the adsorbent, the Langmuir model and the pseudo-second-order kinetic model could describe the adsorption process. The maximum adsorption capacity of ciprofloxacin was 14.409 mg/g. Adsorption thermodynamic studies indicate that adsorption is mainly spontaneous exothermic adsorption.The competitive adsorption was observed in the process of adsorbing in a mixed solution of ciprofloxacin and sulfanilamide. The pseudo-second-order kinetic model fitted the experimental kinetic curve well. And the removal rates of ciprofloxacin and sulfanilamide in mixed antibiotic solution decreased compared with those in single antibiotic solution over whole pH range of this study. This further proved that competitive adsorption did exist between ciprofloxacin and sulfanilamide.