Magnetic core-shell MnFe2O4@TiO2 nanoparticles decorated on reduced graphene oxide as a novel adsorbent for the removal of ciprofloxacin and Cu(II) from water

An efficient nanocomposite adsorbent of magnetic core-shell MnFe2O4@TiO2 nanoparticles loaded on reduced graphene oxide (MnFe2O4@TiO2-rGO) was successfully synthesized via a hydrothermal followed by sol-gel route. By using the ciprofloxacin (CIP) and Cu2+ as target pollutants, the adsorption properties of MnFe2O4@TiO2-rGO were systematically learned as well as the factors dependance on the adsorption properties, such as temperature, adsorption time, initial pollutant concentration and pH. The adsorption thermodynamics and kinetics for CIP and Cu2+ were also explored. According to the experimental results, the maximum adsorption capacities for CIP and Cu2+ are 122.87 and 225.99 mg/g, respectively. Their adsorption behaviors conform to the Langmuir isotherm and follow a pseudo-second-order kinetic model at all temperature. It is proposed that adsorption is spontaneous and endothermic chemisorption. Furthermore, the MnFe2O4@TiO2-rGO adsorbent can be easily recycled from polluted solution by external magnetic field. After the adsorbent recycled 6 times, the adsorption capacities for CIP and Cu2+ could still reach up to 76.56 and 118.45 mg/g, respectively. Based on the excellent adsorption performance, magnetic separation and recycling performance, therefore, it is highly believed that our MnFe2O4@TiO2-rGO adsorbent has huge potential applications in the field of water purification.