Magnetic NiAl-mixed metal oxide with hierarchical structure for dye adsorption

Hierarchical NiAl-layered double hydroxide (LDH) microspheres with flower-like structure were synthesized by a facile and cost-effective ionic liquid assisted hydrothermal method. The magnetic mixed metal oxide (MMO) was obtained by calcinations of hierarchical NiAl-LDH, which demonstrated excellent sorption capacity for rhodamine B.XRD pattern, scanning and transmission electron microscopy images revealed that the obtained MMO microspheres displayed a three-dimensional architecture with flower-like structure. The N₂ adsorption-desorption isotherms illustrated that the MMO sample displayed large specific surfacearea. Prepared MMO as adsorbent exhibited significantly sorption capacity for rhodamine B, much larger than conventional LDHs powdered samples. MMO exhibited excellent sorption-regeneration performances compared with previous reported sample. This will facilitate its repeatable and cyclic usage over a long period, including high activity, long-term durability and cycling stability, owing to excellent magnetic behavior of NiAl-MMO. Therefore, this work provides a promising approach for the design and synthesis of flower-like structured materials with large surface area and high magnetic behavior, which can be potentially used in water treatment, catalysis and even water splitting into hydrogen.