Strategy to improve Cu-BTC metal-organic frameworks performance in removal of Rhodamine B: MD and WT-MtD simulations assessment

Abstract

AbstractWith industry progress, environmental problems have begun to threaten human health. Among them, water pollution is closely related to human life and has attracted researchers’ attention. Hence, coping strategies for these pollutants have become a priority nowadays. Here, we carried out the molecular dynamics (MD) and well-tempered metadynamics simulations to evaluate the interaction of Rhodamine B (Rh B) with a copper (II)-benzene-1,3,5-tricarboxylate metal-organic framework (Cu-BTC/MOF). To design a more efficient dye removal platform, the effect of the -NH2, -OH, and -NO2 functional groups on the efficiency of Cu-BTC/MOF in the adsorption of Rh B is investigated. It is found that the interaction energy of Rh B with -NH2-MOF, -OH-MOF, and -NO2-MOF is about −79.98, −121.87, and −365.55 kJ mol−1, respectively, more than the pristine case. This observation confirms that the functionalization strategy can enhance the Cu-BTC/MOF efficiency. The obtained free energy (FE) values from the metadynamics simulation indicated that for adsorption of Rh B on pristine, -NH2-MOF, -OH-MOF, and -NO2-MOF, the global minimums are located about at −220.47, −234.75, −236.09, and −259.01 kJ mol−1, respectively. The obtained results show that in the two-dimensional FE surfaces, the most stable complex with Rh B belongs to the MOF-NO2 system.