Collaborative Research: Organic Cation Interactions with Soil Aluminosilicates: Structure-Sorption Relationships

Bowdoin College, Brunswick ME

Investigators

Abstract

This project, funded by the Environmental Chemical Sciences Program in the Division of Chemistry at the National Science Foundation, addresses the need for more robust predictors of organic cation interactions with aluminosilicate minerals. Professors Allison MacKay and José Gascon (University of Connecticut) and Dharni Vasudevan (Bowdoin College) in their collaboration will work closely with high school students and teachers to introduce cutting-edge chemistry concepts into public education. Their research activities provide two exciting and coupled avenues to facilitate increased K-12 chemistry literacy: Environmental issues, which are hot topics, and computer-based tools, which permeate our daily lives. The PIs will mentor post-doctoral, graduate and undergraduate researchers through the processes of experimental design, manuscript preparation, and presentations at national professional societies. The PIs will continue their committed record of engaging student researchers from groups underrepresented in the sciences and engineering. The integrated team expertise in engineering (MacKay), chemistry (Vasudevan), molecular modeling (Gascon) and geochemistry (Collaborator Bourg) will enable research team members to develop broader perspectives of their individual research projects. The collaborators will adapt computational biochemistry tools to the prediction of charged organic compound sorption, an important determinant of mobility, reactivity, and bioavailability of pesticides and pharmaceuticals following environmental release to soils. The application of computational tools to environmental chemistry will advance our understanding of structure-sorption effects that are difficult to extract solely from experimental observations. This project examines application of the Linear Interaction Energy (LIE) approximation, a molecular dynamics approach with significant computational cost reductions, to identify contributions of van der Waals and electrostatic energies to overall sorption free energies for test sorbates on the representative soil aluminosilicate, montmorillonite. Results from this research will include mechanistic insights into sorption of environmental contaminants categorized as cationic amines to aluminosilicate minerals. This will advance the development of sorption models, allow the evaluation of LIE approximation methods for environmental chemistry applications, and provide integrated training for a research team of students from Primarily Undergraduate and Research 1 institutions.