Activated carbon was prepared from lignin extracted from rice straw and magnetized using magnetic nickel ferrite nanoparticles and were used to remove tetracycline from aqueous solutions. Structural features and morphology of synthesized adsorbents were investigated using XRD, BET, EDX, SEM, FTIR methods. The specific surface area of pure activated carbon and magnetic activated carbon were obtained 1326.848 and 2137.062 m2/g ,respectively. the presence of Nickel ferrite nanoparticles was confirmed in the samples by FTIR and EDX tests. Then, to eva‎luate the performance of these two adsorbents, adsorption tests for Tetracycline was performed discontinuously. Various parameters were examined for example: The initial concentration of tetracycline was investigated at concentrations of 100-300 mg/l and 250 mg/l was selected as the initial concentration of tetracycline. The determination of optimal amount of adsorbent in the initial values of 0.005, 0.01 and 0.015 g was investigated and the value of 0.01 was selected as the optimal amount of adsorbent. Adsorption capacity was eva‎luated at different pH values in the range of 2 to 11 and the highest adsorption capacity occurred at pH 4. The adsorption kinetics were well matched with the pseudo-second-order kinetic model for both adsorbents. The adsorption isotherm for both adsorbents followed The Langmuir model. The Maximum adsorption capacity at room temperature for pure activated carbon and magnetic activated carbon were obtained 322.58 and 714.28 mg/g , respectively. Thermodynamic studies were performed at temperatures of 293, 303 and 313 K and the results showed that the adsorption process for both adsorbents is spontaneous and endothermic and the regeneration experiments for magnetic adsorbents stated that in the third use of this adsorbent, 53.2% of its initial absorption capacity is maintained.

محمدرضا احساني، حميد زيلويي

مهدي بازرگاني پور

نورالله مير غفاري، محسن محمدي