Surface charge characterization of gibbsite nanoparticles: An atomic force microscope study

Aram Harold Klaassen

Research output: ThesisPhD Thesis - Research UT, graduation UT

66 Downloads (Pure)

Abstract

The interaction of water with mineral surfaces, silica and alumina, is one of the most important chemical reactions occurring in nature. Interfacial water, surface charge and hydration properties play a major role in dissolution, CO2 sequestration, precipitation and sorption processes affecting the composition and quality of natural waters. Mapping the mineral nanoparticles effective surface charge and hydration structure is therefore essential for (geo)chemists and environmental scientists to understand the molecular processes at play.

Currently, the chemical modeling of relatively simple surfaces fails when incorporating for a wide range of salt concentrations and pH values. This is further hampered by the lack of systematic studies that probe a wide range of electrolyte solutions. But also questions like how water molecules form self organized layers at the interface, how these layers depend on the surface crystallinity, whether they are surface charge dependent and the origin of the monotonic hydration are still largely unanswered. In this thesis, I will address some of those questions.

I demonstrate that Atomic Force Microscopy is a useful tool for surface charge characterization of the solid liquid interface with high lateral resolution. This technique provides unprecedented insight into the complex processes involved in the formation of the electric double layer on mineral surfaces. It can resolve the internal structure of the Stern layer, but it can also be used to measure hydration forces of diverse surfaces while simultaneously measuring electric double layer forces. Using these techniques, more materials can be studied in a more systematic fashion. I also demonstrated that our current understanding of the solid liquid interface is far from complete and that the involvement of hydration forces, water ions (like OH–) and surface defects have been underestimated in the past and are not properly taken into account in standard DLVO theory.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • University of Twente
Supervisors/Advisors
  • Mugele, Frieder G., Supervisor
  • Sîretanu, Igor, Co-Supervisor
Award date11 Nov 2020
Place of PublicationEnschede
Publisher
Print ISBNs978-90-365-5071-0
DOIs
Publication statusPublished - 11 Nov 2020

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