UiO-66-NHC(S)NHMe/Three-Dimensional Macroporous Carbon for Removal and Electrochemical Detection of Cd<sup>2+</sup>, Pb<sup>2+</sup>, Cu<sup>2+</sup>, and Hg<sup>2+</sup>
Longsheng Pei, Hanlun Yang, Chen Sh, Li Wang
Abstract
The metal–organic framework (MOF) UiO-66-NH2 was synthesized and attached to kenaf stem-derived three-dimensional macroporous carbon (3D-KSC) simultaneously, and then, the isothiocyanate functional group was introduced into UiO-66-NH2 MOFs to prepare UiO-66-NHC(S)NHMe/3D-KSC nanocomposites. The amount of UiO-66-NHC(S)NHMe MOFs on 3D-KSC can be controlled easily by the monomer concentration. There were three adsorption sites (two nitrogen atoms and one sulfur atom) on each structural unit of UiO-66-NHC(S)NHMe for adsorption toward heavy metal ions (HMIs) and well-regulated pores and 3D macropores of 3D-KSC to promote the transfer of HMIs. Therefore, UiO-66-NHC(S)NHMe/3D-KSC nanocomposites can be applied for the removal and electrochemical detection of Cd2+, Pb2+, Cu2+, and Hg2+. The detection limits of Cd2+, Pb2+, Cu2+, and Hg2+ were 0.0125, 0.0124, 0.0111, and 0.0094 μM, respectively. The sensitivities were 879.1, 887.6, 992.5, and 1160.7 μA μM–1 cm–2, respectively. UiO-66-NHC(S)NHMe/3D-KSC showed fine reproducibility and stability as well as strong anti-interference ability. In addition, the HMIs can be removed effectively by UiO-66-NHC(S)NHMe/3D-KSC with the maximum adsorption capacity of 88, 391, 223, and 935 mg·g–1 for Cd2+, Pb2+, Cu2+, and Hg2+, respectively. The results show that UiO-66-NHC(S)NHMe/3D-KSC has great potential for the adsorption and detection of HMIs.