Synthesis, characterization and aging study of kaolinite-supported zero-valent iron nanoparticles and its application for Ni(II) adsorption

Kaolinite-supported zero-valent iron nanoparticles (kaolinite-nZVI) were prepared by a liquid-phase reduction under ambient atmosphere. The synthesized kaolinite-nZVI particles exist on the surface of clays or form a chain independently. A good dispersion of the swelling black sheer was observed to affix to the surface of kaolinate, and a complete core-shell structure may protect the iron oxide from more hydration. Synthesized nanoparticles were used to adsorb Ni(II) from aqueous solution. It was found that the adsorption of Ni(II) on kaolinite-nZVI was highly pH-dependent, following pseudo second-order kinetics model. The Langmuir isotherm model fits well with the Ni(II) adsorption on kaolinite-nZVI. Kaolinite-nZVI was more times useful, and showed a better adsorption capacity (9.24 mg/g) than nZVI (8.69 mg/g), kaolinite(1.61 mg/g) and ZVI (4.58 mg/g). These works promote the granulation, storage and transportation of nZVI, greatly enhancing the promising in environmental applications. (C) 2014 Elsevier Ltd. All rights reserved.