Removal of antibiotics from aqueous solutions by green synthesized magnetite nanoparticles with selected agro-waste extracts

The present work highlights on efficacy of three types of green synthesized magnetite nanoparticles (Fe3O4 NPs) for the removal of a mixture of seven antibiotics, namely piperacillin (PIP), tazobactam (TAZ), sulfamethoxazole (SUL), tetracycline (TET), trimethoprim (TRI), ampicillin (AMP) and erythromycin (ERY) from aqueous media. Fe3O4 NPs were prepared through an environmentally friendly, facile and economical synthetic route which uses aqueous peel extracts of lemon (Citrus limon), black grapes (Vitis vinifera) and cucumber (Cucumis sativus), and were denoted as Fe3O4(lem), Fe3O4(grp) and Fe3O4(cum), respectively. The magnetic nanoparticles were characterized by XRD, FTIR, SEM, TEM, BET, XPS, and VSM techniques. A Box-Behnken design approach was employed in order to identify the optimum conditions for removal of selected antibiotics. The concentration of antibiotics was determined using high-performance liquid chromatography coupled with diode array detector and mass spectrometer (HPLC-DAD-MS) analysis. The Langmuir, Freundlich and Temkin adsorption isotherm models were used for description of the adsorption equilibrium of studied antibiotics and kinetic studies were conducted. Overall, Fe3O4 NPs synthesized with extracts exhibited high removal (>90%) of studied antibiotics, excepting SUL and TRI, and likewise demonstrated higher efficiency for the purpose of antibiotics removal than Fe3O4 NPs synthesized by a previously reported conventional method.