Three-dimensional macroporous Carbon/Zr-2,5-dimercaptoterephthalic acid metal-organic frameworks nanocomposites for removal and detection of Hg(II)

Mercury ion (Hg(II)) has serious destructive effects on organisms and environments even at extremely low concentration. Therefore, effective removal and highly sensitive determination of trace Hg(II) is very important. Herein, mercaptan functionalized metal-organic frameworks (MOFs) were prepared by the coordination between Zr (IV) and 2,5-dimercaptoterephthalic acid (Zr-DMBD MOFs) and attached to three-dimensional kenaf stem-derived carbon (3D-KSC) to form a novel nanocomposite for removal and electrochemical detection of Hg(II). The sensitivity of Hg(II) detection was 324.58 μA μM−1 cm-2, the linear range was 0.25 μM–3.5 μM and the detection limit was 0.05 μM. The good performances were because lots of Zr-DMBD MOFs were uniformly dispersed on 3D-KSC and the porous Zr-DMBD MOFs had a large number of mercaptan groups to enrich Hg(II) significantly on the electrode. The Hg(II) detection would not be interfered by other co-existing heavy metal ions, and the Zr-DMBD MOFs/3D-KSC also showed excellent stability and reproducibility. Furthermore, the Zr-DMBD MOFs/3D-KSC could effectively remove Hg(II) in real wastewater. The residues were lower than national discharge standard of industrial wastewater (GB30770-2014).