Characterization of Arsenic Adsorption on Metal Oxide Nanoparticles By Nanoimpact Electrochemistry

Metal oxide nanoparticles (MNP) such as titania (TiO2), Ceria (CeO2) and Iron Oxide (Fe3O4) are heavily used in consumer products and discarded in the environment with little regulation. Although these NPs are found to be relatively non-toxic, when released in the environment they can undergo transformation and interact with existing contaminants such as heavy metals which can drastically change their properties and toxicity profile. This presentation will discuss electrochemical studies to investigate the interaction of MNPs with inorganic arsenic species and characterize surface processes (e.g. oxidation, adsorption) at the level of individual particles. Examples of NP systems and studies to assess the effect of particle type, surface coatings and environmental composition will be provided along with the parameters controlling adsorption/desorption of toxicants, using electrochemical methods and a suite of spectroscopic procedures. We demonstrate the use of electrochemistry as a powerful tool to quantifying heavy metal adsorption and determining mechanisms that can be used to predict the interaction of NPs in the environment.