Conformational change of oil contaminants adhered onto crystalline alpha-alumina surface in aqueous solution

WK Xie and YZ Sun and HT Liu and HY Fu and YC Liang, APPLIED SURFACE SCIENCE, 360, 184-191 (2016).

DOI: 10.1016/j.apsusc.2015.10.168

Microscopic conformational change of oil contaminants adhered onto perfect alpha-Al2O3 (0001) surface in the aqueous solution was simulated by means of detailed fully atomistic molecular dynamics simulations. The main driving forces of the conformation change process of the oil contaminants were explored. The simulation results indicate that with submerging of the contaminated alpha-Al2O3 (0001) surface into the aqueous solution, the oil contaminants undertake an evident conformational change process. The dynamic process can be divided into several stages, including early penetration of water molecules, formation and widening of water channel, and generation of molecularly adsorbed hydration layers. Moreover, the oil contaminants on the alpha- Al2O3 surface are not fully removed from solid surface after a 10 ns relaxation, while a relatively stable oil/water/solid three-phase interface is gradually formed. Further, the residual oil contaminants are finally divided into several new ordered molecular adsorption layers. In addition, by systemically analyzing the driving forces for the conformational change of the oil contaminants, the penetration of water molecules is found to be the most important driving force. With penetrating of the water molecules, the dominating interactions controlling the conformational change of the oil contaminants have been changing over the whole simulation. (C) 2015 Elsevier B.V. All rights reserved.

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