Highly efficient ZIF-based adsorbents for the removal of Congo red dye and atorvastatin pharmaceutical pollutant: A study using molecular simulations and DFT calculations

This study presents an innovative strategy to develop high-efficiency adsorbents by functionalizing Zeolitic Imidazolate Framework-8 (ZIF-8) with tetrakis(4-carboxyphenyl)porphyrin (TCPP), targeting the removal of challenging water pollutants"”specifically, Congo Red (CONRED) dye and Atorvastatin (ATORTN) drug residues"”through advanced molecular simulation techniques. Density functional theory (DFT) was applied to analyze the electronic properties of both pollutants and adsorbents, focusing on electrostatic potential, ionization energy, density of states, sigma profile, and Frontier molecular orbitals to provide a detailed picture of molecular reactivity. The properties of the adsorbents were assessed using the dipole autocorrelation function (DACF), isometric heat capacity (Cv), radius of gyration (Rg), density, and bulk and shear viscosity to establish their performance profiles. Molecular dynamics (MD) and Monte Carlo (MC) simulations further explored adsorption behaviors, revealing high adsorption capacities for both pollutants, with ZIF-8/TCPP demonstrating superior adsorption capacity and selectivity, especially for ATORTN over CONRED. These findings underscore the potential of combining molecular simulations with quantum mechanical insights to advance the design of next-generation adsorbents for sustainable environmental remediation.