Nickel nanoparticles encapsulated in porous carbon and carbon nanotube hybrids from bimetallic metal-organic-frameworks for highly efficient adsorption of dyes

Nickel nanoparticles encapsulated in porous carbon/carbon nanotube hybrids (Ni/PC-CNT) were successfully prepared by a facile carbonization process using Ni/Zn-MOF as the precursor. Distinct from previous studies, Ni/Zn-MOF precursors were prepared via a direct precipitation method at room temperature for only 5 min. After the carbonization, magnetic Ni nanoparticles were well embedded in the porous carbon and carbon nanotube. The obtained Ni/PC-CNT composites had a high surface area (999 m2 g−1), large pore volume (0.86 cm3 g−1) and well-developed graphitized wall. The Ni/PC-CNT composites showed excellent adsorption capacity for removal of malachite green (MG), congo red (CR), rhodamine B (Rh B), methylene blue (MB) and methyl orange (MO) from aqueous solution. The maximum adsorption capacity of Ni/PC-CNT composites were about 898, 818, 395, 312 and 271 mg/g for MG, CR, RB, MB and MO dyes, respectively, which were much higher than most of the previously reported adsorbents. Moreover, the Ni/PC-CNT composites could be easily regenerated by washing it with ethanol and easy magnetic separation.

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