Co-adsorption and sequential adsorption of the co-existence four heavy metal ions and three fluoroquinolones on the functionalized ferromagnetic 3D NiFe2O4 porous hollow microsphere.

Functionalized magnetic microsphere NiFe2O4 (MS-NiFe2O4) with a 3D hierarchical porous hollow structure was fabricated using urea as the modifier and soft templates by a simple one-pot solvothermal method. The constructed MS-NiFe2O4 shows excellent dual functions which can not only undergo simultaneous rapid removal of the co-existence metal ions (Cu2+, Cd2+, Cr3+ and Zn2+ ions), but also availably adsorb fluoroquinolone (FQs) (ciprofloxacin (CIP), enrofloxacin (ENR) and norfloxacin (NOR)), and is easily recycled using an external magnetic field. The removal efficiency of eight targets could all reach up to 80% within 60min at pH 5. The independent adsorption of single contaminants, the competitive adsorption of multiple heavy metal ions/organic contaminants, the simultaneous and sequential adsorption of the co-existence of inorganic and organic contaminants onto MS-NiFe2O4 were explored in detail. Competition adsorption occurred between the same type of contaminants. For different types of contaminants, four metal ions did not affect the adsorption of the other three FQs in the sequential and simultaneously adsorption system, and vice versa. The possible adsorption mechanism between targets and MS-NiFe2O4 was revealed.