Competitive Adsorption of a Multifunctional Amine and Phenol Surfactant with Ethanol on Hematite from Nonaqueous Solution.

Surfactants, which contain phenol and amine groups, are commonly used in industries to protect metallic surfaces, and their efficiency depends strongly on factors such as pressure and temperature, solvent properties, and the presence of other surfactants in the system. In this work, we present a molecular simulation study of the competitive adsorption between a multifunctional phenol and amine surfactant model and ethanol at the oil/solid interface formed between iso-octane and a model hematite (α-FeO) slab. We show that the surfactant strongly adsorbs at the iso-octane/hematite interface in the absence of ethanol at moderate temperatures.

Liquid Adsorption of Organic Compounds on Hematite α-FeO Using ReaxFF.

ReaxFF-based molecular dynamics simulations are used in this work to study the effect of the polarity of adsorbed molecules in the liquid phase on the structure and polarization of hematite (α-FeO). We compared the adsorption of organic molecules with different polarities on a rigid hematite surface and on a flexible and polarizable surface. We show that the displacements of surface atoms and surface polarization in a flexible hematite model are proportional to the adsorbed molecule's polarity.