Atomistic modeling of the sorption free energy of dioxins at clay-water interfaces

Thomas V. Shapley, Marco Molinari, Runliang Zhu, Stephen C. Parker

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We employed dispersion corrected DFT and classical methods to identify the factors controlling the adsorption and intercalation of dioxins at water-clay mineral interfaces including sodium and organo-montmorillonites (Na-, TMA-, and HDTMA-Mont) and pyrophyllite. To evaluate the intrinsic sorptive capacity of the clay minerals, the sorption free energies of dioxins at the clay {001} surfaces were calculated, and this showed that the hydrophobicity of the surface is a factor controlling the adsorption. The intercalation of dioxins from the external solvent into the interlayer space of clays was also evaluated, showing the importance of the presence of organic cations. We found that organoclays have sufficient hydrophobicity with large organic cations, and this coupled with the swelling properties of montmorillonite ensures effective adsorption from an aqueous environment. HDTMA-Mont is shown to have these features and that the dioxins were immobilized within the long alkyl chains of the counterions.

Original languageEnglish
Pages (from-to)24975-24984
Number of pages10
JournalJournal of Physical Chemistry C
Volume117
Issue number47
DOIs
Publication statusPublished - 27 Nov 2013
Externally publishedYes

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