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

•A good dispersion of the swelling black sheer was observed to affix onto the surface of kaolinate.•A complete core–shell structure may protect the iron oxide from more hydration.•Kaolinite–nZVI showed a better adsorption capacity than nZVI, kaolinite and ZVI.

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.

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