Adsorption dynamics and intrinsic mechanism of POPs on corrole-based COF: A computational study

Abstract

Highly efficient removal of persistent organic pollutants (POPs) by novel porous materials such as covalent organic frameworks (COFs) has aroused widespread attention in environmental remediation. A thorough understanding on the removal mechanism lays a foundation for the material design. In the present work, the adsorption process of POPs on corrole-based COF (TPAPC) and their intrinsic interaction mechanism have been systematically investigated at the molecular level utilizing molecular dynamics (MD) simulations and density functional theory (DFT) calculations. A dynamic three-step adsorption pathway for POPs molecules, involving irregular movement, surface adsorption and interlayer transferring was vividly presented through the analysis of MD trajectory. TPAPC, especially its corrole moieties, exhibited tremendous adsorption capacity for POPs and the van der Waals (vdW) interaction played a dominant role during the adsorption process. Polychlorinated biphenyl (PCB) molecules (−2.15 ∼ −5.62 kcal/mol) exhibited much higher adsorption free energies than biphenyl (−0.68 kcal/mol), indicating their stronger binding capacities with TPAPC. Based on DFT calculations, the negative vdW potentials of corrole moiety and PCB molecules endowed them to become the preferable adsorption site and adsorbate, respectively. Our findings not only demonstrated that the corrole-based COF can be considered as a promising adsorbent for removing POPs but also provided a theoretical basis for designing novel COFs materials with specific functional groups such as corrole moiety in the field of environmental remediation.