Research School for Socio-Economic and
Natural Sciences of the Environment
Research School for Socio-Economic and
Natural Sciences of the Environment

Bastiaan Molleman

Date: 11 October 2019
Time: 11:00 - 12:30
Location: Aula, building 362, Gen. Foulkesweg 1, Wageningen

Dissertation title: 

Skimming the surface - A surface structural approch to understanding silver ion release from silver nanoparticles

Group: Wageningen University, Soil Chemistry and Chemical Soil Quality
Promotor: Prof.dr. R.N.J. Comans
Co-promotor: T. Hiemstra

Extra information:


Silver nanoparticles are used in a variety of consumer products and may end up in our environment. In the environment, silver nanoparticles can negatively affect microorganisms, plants, microfauna, and macrofauna due to release of toxic silver ions. However, the process of silver ion release is poorly understood hindering predictions of environmental impact. In this thesis, silver ion release is studied from a surface structural perspective. A hypothetical surface structure is presented based on crystallographic and spectroscopic data and first principles calculations. Based on the proposed structure, a chemical model for the release of silver ions is developed and evaluated experimentally. Both dissolution kinetics and equilibrium concentrations are in excellent agreement with model calculations. Additionally, the model reveals the vital role of surface energy in determining the size dependency of silver ion release. This phenomenon is further studied in detail from a thermodynamic and from an atomic perspective.