A first principle evaluation of the adsorption mechanism and stability of volatile organic compounds into NaY zeolite

Abstract

Removal of volatile organic compounds (VOCs) from indoor or outdoor environments is an urgent challenge for the protection of human populations. Inorganic sorbents such as zeolites are a promising solution to tackle this issue. Using dispersion corrected periodic DFT calculations, we have studied the interaction between sodium-exchanged faujasite zeolite and a large set of VOCs including aromatics, oxygenates and chlorinated compounds. The computed interaction energies range from about −25 (methane) to −130 kJ/mol (styrene). Methane is by far the less interacting specie with the NaY zeolite. All other VOCs present interaction energies higher in absolute value than 69 kJ/mol. Most of them show a similar adsorption strength, between −70 and −100 kJ/mol. While the electrostatic interactions are important in the case of oxygenates and acrylonitrile, van der Waals interactions predominate in hydrocarbons and chlorides. By monitoring the variation of molecular bond lengths of the different VOCs before and after adsorption, we have then evaluated the tendency of adsorbate to react and form by-products, since a significant stretching would evidently lead to the activation of the bond. While hydrocarbons, tetrachloroethylene and acrylonitrile seem to be not activated upon adsorption, all oxygenates and 1,1,2-trichloroethane could possibly react once adsorbed.

Leaching and Reactivity at the Sodium Aluminosilicate Glass–Water Interface: Insights from a ReaxFF Molecular Dynamics Study

“…The distance between water and Na + ions shows both the solvation of Na + ions and the adsorption and penetration of water into the first layers of the glass surface. This adsorption distance between O W and Na is in good agreement with the previous density functional theory (DFT) calculations. − As in the nonhydrated NAS model, oxygen atoms from water molecules are bound to the glass in the following order: Si–O W < Al–O W < Na–O W . In the same context, some oxygen atoms from water molecules did not immediately move in which the O W stuck to the surface.…”

Biofuel purification: Coupling experimental and theoretical investigations for efficient separation of phenol from aromatics by zeolites

“…The Kohn-Sham equations have been iteratively solved until the energy difference between the cycles becomes lower than 10 −6 eV. Previous investigations [37,[48][49][50][51] have demonstrated the need to consider van der Waals (vdW) interactions to accurately describe the adsorption of molecules in zeolites, Herein, we have used the very recent FI/MDB dispersive correction method. [52] As in the original MDB method, [53,54] the FI/ MDB oversees a simple pairwise correction taking into account the many-body interactions while taking fully account for the ionicity of atoms.…”

Atomic Insights into the Events Governing the Borosilicate Glass–Water Interface

“…To take into account van der Waals interactions in our calculations, we used the semiempirical scheme D2 developed by Grimme . This level of theory has been proven to deal with silica-based materials and water adsorption. , Herein, the adsorption phenomena were studied by determining the interaction energy Δ E int , which is calculated by combining three energy terms, − as follows where E G is the energy of the clean NBS glass surface, E W is the energy of the single molecule, and E G+W is the energy of NBS and the water molecule. To assess the contribution of each atom to the water adsorption and the possible charge transfers between water and the NBS glass surface, we have calculated the difference in electronic density (Δρ) and the difference in charge (Δ Q ) using Bader charge analysis.…”