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

作者：Jingping Zhong; Jian Zhou; Minsi Xiao; Jun Liu; Jili Shen; Juan Liu; Sili Ren^*

来源：Chinese Chemical Letters, 2022, 33(02): 973-978.

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.