Ion adsorption at mineral-electrolyte interfaces: from atomic scale AFM imaging to macroscopic wetting alteration

Description

The distribution of ions and charge at solid-water interfaces plays an essential role in a wide range of processes in nature, science, and technology, including amongst many others the recovery of crude oil from geological reservoirs. While theoretical models of the solid-electrolyte interface date back to the early 20th century, experimental techniques largely rely on macroscopic averaging and therefore lack the spatial resolution to test key predictions. Making use of recent advances in high-resolution Atomic Force Microscopy (AFM) we show with atomic level precision how cations common in natural environments adsorb to heterogeneous mineral-electrolyte interfaces and thereby alter the electrostatic and chemical properties of the surface. In combination with density functional theory calculations, the experiments reveal a detailed picture of the formation of surface phases by templated adsorption of ions under the influence of electrostatic and hydration forces. These changes of the microscopic surface chemistry have dramatic consequences for the affinity of organic solutes and amongst others for the macroscopic wettability of the surfaces: mica surfaces immersed in ambient decane, display a transition from complete water wetting to partial wetting depending on the affinity of preferentially multivalent cations to the solid-electrolyte interface. This phenomenon is believed to play a major role for the success of modern technologies of enhanced oil recovery, in particular so-called Low Salinity Water Flooding

Period	22 May 2018 → 25 May 2018
Event title	16th Conference of the International Association of Colloid and Interface Scientists 2018
Event type	Conference
Conference number	16
Location	Rotterdam, Netherlands
Degree of Recognition	International