Preparationof Magnetic Composite Hollow Microsphereand Its Adsorption Capacity for Basic Dyes.

Magneticmicrospheres with an Fe3O4coreand a SiO2–TiO2hybrid shell were preparedby a surfactant-assisted aerosol process and subsequent etching treatment.The core–shell spheres with robust and chemically stable Ti–O–Sishells exhibit excellent adsorption performance toward basic dyes.The maximum adsorption capacities were obtained at 147 mg/g for methyleneblue (MB) and 124.6 mg/g for basic fuchsin. MB with an initial concentrationof 20 mg/L can be completely removed in 5 min at a dosage of 0.5 mg/L,and the equilibrium time is 90 min in the MB concentration range 20–250mg/L. The adsorption kinetics follows the pseudo-second-order model.Furthermore, the dye saturated microspheres can be easily recycledby an external magnetic field and regenerated using 1–3 wt% NaOH aqueous solution. After six recycle runs, 98% of the adsorptioncapacity was still retained. The low-cost magnetic hollow sphereswith good adsorption capacity are a promising candidate for watertreatment. [ABSTRACT FROM AUTHOR]