Developed magnetic Fe3O4–MoO3-AC nanocomposite for effective removal of ciprofloxacin from water

Abstract The presence of residual antibiotics or their intermediates as wastes in aquatic systems has motivated more research studies toward exploring new effective antibiotics removal technologies from their waste matrices. Therefore, the present study is devoted to fabricate novel magnetic adsorbents, Fe3O4–MoO3 and Fe3O4–MoO3-AC, by simple coprecipitation method and cross linkage via formaldehyde. The characterization of magnetic adsorbents were confirmed by different techniques such as scanning electron microscope (SEM), transmission electron microspore (TEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET). The characterized specific surface areas and pore volumes of Fe3O4–MoO3 and Fe3O4–MoO3-AC were (39.510 m2 g−1 and 0.1238 cm3 g−1) and (99.063 m2 g−1 and 0.1963 cm3 g−1), respectively. The TGA of Fe3O4–MoO3 showed two degradation steps with 0.684 and 0.834% percentage losses in the temperature range 25–800 °C, while the TGA of Fe3O4–MoO3-AC produced four dissimilar steps with percentage losses corresponding to 4.736, 3.596, 3.849 and 14.019%. The study showed that the modification of Fe3O4–MoO3 by activated carbon enhanced the removal of ciprofloxacin molecule (CPF). Various factors that impacted on the adsorption process were utilized and optimized for example pH, dosage, CPF concentration, shaking time and interfering ions. Four models of adsorption isotherm as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) were investigated for removal of CPF onto magnetic adsorbents. The obtained coefficients (R2) by Langmuir model were (R2 = 0.990 by Fe3O4–MoO3 & R2 = 0.993 by Fe3O4–MoO3-AC) greater than the other models. The thermodynamics studies were appraised and stated that the removal process is endothermic and spontaneous. Pseudo-second-order was shown as the best fit model based on the obtained values R2 in case of Fe3O4–MoO3 and Fe3O4–MoO3-AC as 0.983 and 0.990, respectively.