Boosting adsorption of ciprofloxacin on Fe3O4 nanoparticles modified sepiolite composite synthesized via a vacuum-filtration assisted coprecipitation strategy

Treatment of antibiotics-containing wastewater is imperative for ensuring environmental and public health. However, effectively removing antibiotics in environment is still a great challenge. Fabrication of sepiolite-supported iron oxide nanomaterials with large specific surface area and high reactivity is a promising solution for efficient antibiotics removal. In this work, a highly dispersed Fe 3 O 4 nanoparticle modified sepiolite composite (Fe 3 O 4 -sep-vacuum) was synthesized in-situ by employing a novel vacuum-filtration assisted coprecipitation strategy for the first time. Fe 3 O 4 -sep-vacuum exhibited the highest adsorption capacity to ciprofloxacin compared with those of pure Fe 3 O 4 nanoparticles, sepiolite, and those composites obtained by traditional coprecipitation methods. Approximately 93 % of CIP (20 mg/L) could be removed by Fe 3 O 4 -sep-vacuum within 20 min at initial pH 6.0. The kinetic and adsorption isotherms followed pseudo-second-order and Temkin models, respectively. The maximum adsorption capacity (q m ) of Fe 3 O 4 -sep-vacuum for CIP was 18.4 mg/g at initial pH 6.0. The solution pH, temperature, coexisting divalent cations, and HA concentration were demonstrated to play substantial roles in the adsorption processes of ciprofloxacin on Fe 3 O 4 -sep-vacuum surface. The Fe 3 O 4 -sep-vacuum maintained excellent stability and reusability during CIP adsorption process. Electrostatic interactions play a decisive role in the adsorption process of ciprofloxacin by Fe 3 O 4 -sep-vacuum. Hydrogen bonds and hydroxyl groups on the Fe 3 O 4 -sep-vacuum surface also play important roles in the adsorption process of ciprofloxacin. Fe 3 O 4 -sep-vacuum also exhibited excellent adsorption capacity to ofloxacin. These results indicate that the vacuum-filtration assisted coprecipitation strategy could be used to fabricate monodispersed nanoparticles modified sepiolite composites, which could be acted as promising materials for highly efficient remediating antibiotics contaminated wastewater.