Adsorption of 2-4-6.trichlorophenol on montmorillonite surface: ONIOM study

Abstract

The wastewater contains several chemicals, organic and inorganic molecules, among themolecules, 2.4.6-trichlorophenol, which is a source of contamination. The main aim of this work is to distinguish the process of 2.4.6-trichlorophenol retention with montmorillonite using QM: MM-ONIOM approach and applying local and global reactivity parametersthatare an excellent key for identifying adsorption sites. A weak hydrogen bond between the hydroxyl proton of 2,4,6-trichlorophenol molecule and oxygen atom on the montmorillonite surface, with a specific distance, Hb = 2.66 Å using M06-2X functional) has proved the physical adsorption. Thermochemical analysis reveals the exothermic nature of adsorption process. Negative ΔH values signify heat release and negative ΔG values indicating spontaneity under standard conditions.Theobtained results have proved an agreement with other experimental and theoretical data.