Metal-catechol group modified Zr-based MOFs for efficient SO2 trapping: GCMC and DFT study

Sulfur dioxide (SO2) is a polluting gas that poses a significant threat to the environment and human health. Adsorption and removal of SO2 is an effective means in its control process, and MOFs have garnered widespread attention due to their immense potential in the field of gas adsorption. In this paper, the adsorption process of SO2 in the pore structures of three Zr-based MOF materials, UiO-66, MFM-601, and HBU-20, was firstly simulated based on MD and GCMC. The ability of different pore structures to adsorb SO2 gas at varying temperatures and pressures was analyzed with emphasis. Subsequently, the three MOFs were modified by introducing metal-catechol into each of them. The effect of Cat(M) (M = Cr, Mn, Fe, Ni, Cu, Zn) on the SO2 adsorption properties of the MOF materials was deeply analyzed based on DFT. The results indicated that the introduction of Cat(M) significantly enhanced the adsorption capacity of UiO-66 and MFM-601 for SO2. Notably, UiO-66-Cat(Cu) and MFM-601-Cat(Cu) exhibited the most significant enhancement effects, reaching 30.8 % and 102.7 %, at room temperature and pressure. Furthermore, Cat(M) enhanced the thermal stability of UiO-66 and MFM-601. These findings hold guiding significance for the study of MOF modification for the removal of SO2 gas.