Chemistry
Presenter(s): Abby Kim
Advisor(s): Dr. Christopher Kim
Iron oxyhydroxide nanoscale particles are naturally occurring and ubiquitous in aquatic environments. Nanoparticles have high surface charges and react with a wide range of dissolved ions and contaminants. Furthermore, the mobility and aggregation state of nanoparticles are highly dependent on geochemical changes such as pH fluctuation, concentrations of organic matter, and salinity. Because of the many variables that pertain to the adsorption and retention of the nanoparticles, we concentrated on the effects of organic matter on the aggregation of the nanoparticles and the nanoparticle aggregates’ retention properties at varying organic matter concentrations. The goals of this project are to observe, characterize, and classify the changes and reactions occurring between the nanoparticle aggregates, organic matter, and metal contaminants using dynamic light scattering (DLS) analysis to measure the average size of the aggregates and inductively coupled plasma – optical emission spectrometry instrument (ICP-OES) to measure the adsorption and retention of a contaminant metal to the aggregates. The DLS analysis of the nanoparticle aggregates at varying concentrations of organic matter yielded an increasing trend in size as the organic matter concentration increased. The ICP-OES analysis also showed an increasing trend of adsorption and retention of Zn(II) ions as the organic matter concentration increased. With these results, the adsorption and retention properties of the nanoparticles and their aggregates can be optimized using an increasing amount of organic matter. Additionally, the aggregation of the nanoparticles may affect the efficacy of the aggregates’ adsorption and retention properties.