Capture of pure toxic gases through porous materials from molecular simulations

In the last three decades, the air pollution is the main problem to affect human health and the environment in China and its contaminants include SO_2, NH_3, H₂S, NO₂, NO and CO. In this work, we employed grand canonical Monte Carlo simulations to investigate the adsorption capability of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for these toxic gases. Eighty-nine MOFs and COFs were studied, and top-10 adsorption materials were screened for each toxic gas at room temperature. Dependence of the adsorption performance on the geometry and constructed element of MOFs/COFs was determined and the adsorption conditions were optimised. The open metal sites have mainly influenced the adsorption of NH₃, H₂S, NO₂ and NO. Especially, the X-DOBDC and XMOF-74 (X = Mg, Co, Ni, Zn) series of materials containing open metal sites are all best performance for adsorption of NH₃ to illustrate the importance of electrostatic interaction. Our simulation results also showed that ZnBDC and IRMOF-13 are good candidates to capture the toxic gases NH_3, H₂S, NO₂, NO and CO. This work provides important insights in screening MOF and COF materials with satisfactory performance for toxic gas removal.