Design and syntheses of functionalized copper-based MOFs and its adsorption behavior for Pb(II)

A novel copper-based MOFs adsorbent (Cu-BTC-Th) was prepared using an one-step method by introducing a new organic ligand of 4-thioureidobenzoicacid (Th) with active groups for selectively adsorbing Pb(II) from aqueous solutions. The chemical composition and structure of the prepared MOFs materials were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Brunner-Emmet-Teller (BET) analysis, and zeta potential measurements. The adsorption capability of the prepared Cu-MOFs was significantly enhanced by introducing the new organic ligand of Th in the materials. The maximum adsorption capacity of the Cu-BTC-Th for Pb(II) attains 732.86 mg/g under the optimal conditions. In addition, the adsorption kinetics and adsorption isotherm analysis showed that the adsorption process followed the pseudo-second-order kinetic model and Langmuir adsorption model, indicating that the adsorption of Pb(II) by Cu-BTC-Th was a monolayer chemisorption. The adsorption mechanism of Cu-BTC-Th for Pb(II) was discussed and revealed. On one hand, the adsorption of Pb(II) is mainly through ion exchange with the Cu(II). On the other hand, the - NH2 and - C=S functional groups introduced in the Cu-BTC-Th materials have stronger coordination ability with the Pb(II) ions to enhance the adsorption capability. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

A novel copper-based MOFs adsorbent (Cu-BTC-Th) was prepared by introducing a new organic ligand of 4-thioureidobenzoic acid (Th) to enhance the selective adsorption of Pb(II) from aqueous solutions. The adsorption capacity of Cu-BTC-Th for Pb(II) was significantly enhanced, reaching a maximum of 732.86 mg/g under optimal conditions. The adsorption mechanism was discussed, involving ion exchange with Cu(II) and coordination of functional groups in Cu-BTC-Th with Pb(II) ions.