Highly efficient removal of antibiotic rifampicin from aqueous solution using green synthesis of recyclable nano-Fe3O4

Antibiotics in water and soil are persistent, bioaccumulative and toxic to aquatic organisms and human health. To address it, as one of the new technologies, green synthesized magnetic Fe3O4 nanoparticles by Excoecaria cochinchinensis extract used to remove rifampicin (RIF) was investigated in this study. Results showed the adsorption efficiency of RIF reached 98.4% and the maximum adsorption capacity is 84.8 mg/g when 20 mL of RIF at a concentration of 20 M was adsorbed by 10 mg Fe3O4 at a temperature of 303 K. The morphology of the green Fe3O4 characterized by SEM demonstrated the dimensions ranging from 20 to 30 nm. The N-2 adsorption/desorption isotherms revealed that the surface area of Fe3O4 was 111.8 m(2)/g. In addition, adsorption studies indicated that the kinetics fitted the pseudo second-order and isothermal adsorption conformed to the Langmuir isotherm. Furthermore, due to their magnetic properties, the Fe3O4 nanoparticles were easily separated and reused and the mechanism for removing RIF occurred through adsorption rather than chemical redox reaction. Finally, the reusability of Fe3O4 for adsorption of RIF showed that the removal efficiency decreased to 61.5% after five cycles. (C) 2019 Elsevier Ltd. All rights reserved.