title: Molecular dynamics simulation of TCDD adsorption on organo-montmorillonite.
abstract: In this work, molecular dynamics simulation was applied to investigate the adsorption of Tetrachlorodibenzo-p-Dioxin (TCDD) on tetramethylammonium (TMA) and tetrapropylammonium (TPA) modified montmorillonite, with the aim of providing novel information for understanding the adsorptive characteristics of organo-montmorillonite toward organic contaminants. The simulation results showed that on both outer surface and interlayer space of TPA modified montmorillonite (TPA-mont), TCDD was adsorbed between the TPA cations with the molecular edge facing siloxane surface. Similar result was observed for the adsorption on the outer surface of TMA modified montmorillonite (TMA-mont). These results indicated that TCDD had stronger interaction with organic cation than with siloxane surface. While in the interlayer space of TMA-mont, TCDD showed a coplanar orientation with the siloxane surfaces, which could be ascribed to the limited gallery height within TMA-mont interlayer. Comparing with TMA-mont, TPA-mont had larger adsorption energy toward TCDD but smaller interlayer space to accommodate TCDD. Our results indicated that molecular dynamics simulation can be a powerful tool in characterizing the adsorptive characteristics of organoclays and provided additional proof that for the organo-montmorillonite synthesized with small organic cations, the available interlayer space rather than the attractive force plays the dominant role for their adsorption capacity toward HOCs.
authors.affiliation: Department of Environmental Science and Engineering, Xiangtan University, Xiangtan 411105, China. zhurunliang@gmail.com
authors.forename: Runliang
authors.initials: R
authors.lastname: Zhu
authors.forename: Wenhao
authors.initials: W
authors.lastname: Hu
authors.forename: Zhimin
authors.initials: Z
authors.lastname: You
authors.forename: Fei
authors.initials: F
authors.lastname: Ge
authors.forename: Kaixun
authors.initials: K
authors.lastname: Tian
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D000072317:Polychlorinated Dibenzodioxins / Q000737:chemistry*
chemical_list: D000072317:Polychlorinated Dibenzodioxins; D001546:Bentonite