Superior adsorption performance of metal-organic-frameworks derived magnetic cobalt-embedded carbon microrods for triphenylmethane dyes

In this work, magnetic Co/C microrods were successfully synthesized using direct carbonization of [Co-3(BTC)(2)(H2O)(12)] precursors. After the carbonization, the original shape of the precursors was well maintained, while the magnetic Co nanoparticles were well dispersed in the carbon matrix. The Co/C microrods were used as adsorbents for the adsorption of methyl blue (MB), acid fuchsin (AF), malachite green (MG), rhodamine B (Rh B), methyl orange (MO) and methylene blue (MTB) from their aqueous solutions. The results show that Co/C microrods can selectively adsorb triphenylmethane (TPM) dyes, while the adsorption capacities are about 13960, 11,610 and 4893 mg/g for MB, AF and MG dyes, respectively. The adsorption mechanism can be attributed to pi-pi interaction forces between the sp(2) graphitic carbon in Co/C microrods and the triphenyl structure of dyes. In addition, the synthesized magnetic Co/C micro rods can be easily removed from water using magnetic separation, and subsequently, regenerated using ethanol treatment. (C) 2018 Published by Elsevier Inc.