Colloids and Surfaces A: Physicochem. Eng. Aspects 520 (2017) 324–334 Contents lists available at ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects j ourna l h om epa ge: www.elsevier.com/locate/colsurfa Change of organobentonite interlayer microstructure induced by sorption of aromatic and petroleum hydrocarbons—A combined study of laboratory characterization and molecular dynamics simulations Mohammad Ghavami a , Qian Zhao a,∗ , Sadra Javadi a , John Samuel Dilip Jangam b , Jacek B. Jasinski c , Nina Saraei d a Department of Civil and Environmental Engineering, University of Louisville, Louisville, KY, 40292, USA b Rapid Prototyping Center and Department of Industrial Engineering, University of Louisville, Louisville, KY, 40292, USA c Conn Center for Renewable Energy and Department of Chemical Engineering, University of Louisville, Louisville, KY, 40292, USA d Department of Chemistry, University of Louisville, KY, 40292, USA h i g h l i g h t s • Lab tests were conducted to quantify the change of microstructure of ben- tonite due to successive intercalation. • The XRD and TEM results confirmed the interlayer expansion of bentonite due to primary and secondary sorp- tion. • Molecular simulations were con- ducted to study the microstructure of clay/surfactant/sorbate hybrids. • FT-IR results indicated a rearrange- ment mechanism of surfactant chains within the organoclay interlayers after secondary sorption. • Both experimental and simula- tion results yield insights into the engineering behaviors of organic-modified clays. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Received 9 November 2016 Received in revised form 12 January 2017 Accepted 13 January 2017 Available online 28 January 2017 Keywords: Montmorillonite Organic surfactant Microstructure Interlayer expansion Hydrocarbon sorption a b s t r a c t In this study, the impact of secondary sorption of hydrocarbons on the interlayer morphology of organic surfactant modified montmorillonites was studied. Montmorillonites intercalated with two quaternary ammonium surfactants, hexadecyltrimethylammonium (HDTMA + ) and bis (hydrogenated tallow alkyl) dimethyl ammonium were chosen as the soil sorbents to uptake naphthalene and gasoline. Labora- tory characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) were carried out, and molecular dynamics (MD) simulations were performed. The successive interlayer expansion of montmorillonites due to the intercalation of surfactants and hydrocarbons were measured by XRD and TEM. FT-IR was employed to verify the interca- lation of organic surfactants and sorbates. Additionally, the MD modeling was conducted to demonstrate the interlayer microstructure of organoclays and to quantify interactions between minerals, surfactants, ∗ Corresponding author at: University of Louisville, WS Speed 119, 2301 S 3rd St., Louisville, KY, 40292, USA. E-mail addresses: m.ghavami@louisville.edu (M. Ghavami), qzgeotech@gmail.com (Q. Zhao), sadra.javadi@louisville.edu (S. Javadi), djjang01@louisville.edu (J.S.D. Jangam), j0jasi01@louisville.edu (J.B. Jasinski), n0sara01@louisville.edu (N. Saraei). http://dx.doi.org/10.1016/j.colsurfa.2017.01.038 0927-7757/© 2017 Elsevier B.V. All rights reserved.