Abstract—In recent decades, the need for producing adsorbents with high absorption capacity and easy separation has led to preparation of magnetic absorbents. In this study, green synthesis of iron oxide/cellulose nanocomposite was used to remove metronidazole from aquatic solutions by application of aqueous extract of spent tea waste regarding its effective and magnetic separation capability. The properties of the synthesized nanocomposite was determined by several advanced techniques, including, X-ray spectroscopy, electron microscopy imaging, thermal analysis and magnetometry. The capability of the nanocomposite adsorption in removal of metronidazole from aqueous solution was evaluated by optimizing four important parameters (pH, initial concentration of metronidazole, amount of nanocomposite and contact time). Different equilibrium isotherms and kinetic models were tested to determine the mechanism and kinetics of adsorption. X-ray diffraction patterns and electron microscopic images showed that the prepared nanocomposite had spherical particles with an average size of at least 15.5 nm. pH of 5, concentration of 10 mg/L of metronidazole, nanocomposite amount of 25 mg/L and time of 30 min were determined to form the optimal operating conditions, with the removal efficiency of 97.04%. The best model for fitting the experimental data were Langmuir isotherm with a maximum adsorption capacity of 332 mg/g and pseudo-first-order kinetic model with a constant rate of 1.15 L/min and a correlation coefficient of 0.97. The prepared nanocomposite was proposed to be studied in drug delivery systems for its high adsorption capacity, suitable magnetic properties and environmental application.
