Evaluation the efficiency of magnetic-metallic chitosan nanocomposite adsorbent in the removal of tetracycline antibiotic from aqueous solutions

Background and Objective: Antibiotics are considered due to health and environmental problems and therefore they counted as a major threat to human health. The aim of this study was to determine the absorption efficiency of magnetic-chitosan nanocomposite in the removal of antibiotic tetracycline from aqueous solutions. Materials and Method: In this study, the experiments were performed by spectrophotometer. The magnetic-chitosan nanocomposite were considered as an antibiotic adsorbent which its adsorption efficiency was measured by changing the variables such as temperature, time, PH, dosage of magnetic-chitosan nanocomposite, concentration of tetracycline, concentration of interactive ions of chlorine, sulfate and carbonate. Synthesis of magnetic-chitosan nanocomposite was based on co-precipitation method. The Freundlich, Langmuir and Temkin isotherms were used to determine the isotherm and the absorption kinetics. Results: The results showed that the best antibiotic removal efficiency was obtained at pH = 6. The highest removal efficiency was obtained at 90 minutes and equal to 91.23%. Moreover, the removal efficiency of tetracycline was significantly reduced in alkaline pH. Also, by increasing the absorbent dose from 0.1 g/L to 0.5 g/L, the removal efficiency of the pollutant increased from 72.24% to 90.22% at 90 minutes. In addition, with an increase in pollutant concentration between 5-30 mg/L, the removal efficiency of the pollutant decreased from 93.4% to 53.7%. In order to study the thermodynamics of the tetracycline pollutant absorption process by magnetic-chitosan nanocomposite, the removal efficiency of the pollutant dropped from 91.23% to 45.1% at 20, 30 and 45 degrees of Celsius. The presence of interfering ions has a decreasing effect on the removal efficiency of tetracycline, which the removal efficiency were reduced from 91.23% at 90 minutes (in the absence of ions) to 70.16% (for chlorine ion), 65.96% (for ion Carbonate) and 54.2% (for sulfate ions).                Conclusion: Finally, the use of magnetic- chitosan nanocomposite adsorbent is recommended in the removal of antibiotic tetracycline.