Postsynthetic modification of copper terephthalate metal-organic frameworks and their new application in preparation of samples containing heavy metal ions

In this paper, a novel thiol-functionalized porous metal-organic frameworks (MOFs), namely thiol-functionalized [Cu4O(BDC)](n) (BDC = Terephthalic acid), was synthesized: The successful modification was certified by Fourier transform infrared spectroscopy and X-ray powder diffraction. The modified MOFs were further characterized by scanning electron microscopy and thermogravimetric measurements. The adsorption of the modified MOFs for both common and heavy metals was investigated. The modified MOFs showed remarkable and selective adsorption for four heavy metals (Hg2+, Cr6+, Pb2+, Cd2+), especially for Hg2+. The dynamic and static adsorption tests showed that the modified MOFs exhibited high adsorption capacity and selectivity for Hg2+, and offered a fast kinetics for the adsorption of Hg2+. The as-synthesized modified MOFs were successfully used as adsorbents to selectively enrich the above four heavy metals in preparation of a tea sample. The results indicate that functionalized MOFs by postsynthetic modification have a promising potential in preparation of samples containing heavy metal ions. (c) 2015 Elsevier Inc. All rights reserved.