UNS: Engineered Nanomaterial Impact on Long-Term Stability of MSW Landfill and Leachate Treatment Pond Geomembrane Liners

University Of South Carolina At Columbia, Columbia SC

Investigators

Abstract

1510869 Berge As engineered nanomaterial-containing products reach the end of their useful life, they will likely reside in municipal solid waste landfills. Work conducted in the principal investigator's (PI's) laboratory at the University of South Carolina suggests that the mobility of carbon nanotubes, examples of engineered nanomaterials, may be significant in waste environments containing "mature" leachate (consisting primarily of humic acid). The main goal of this research is to conduct experiments and perform molecular modeling simulations to understand the implications associated with engineered nanomaterial-geomembrane interactions in municipal solid waste landfills. Engineered nanomaterial production continues to increase: therefore it is inevitable that engineered nanomaterial-containing products/wastes will end up in landfills. Unfortunately, there are no processes or research to evaluate whether currently designed and operating landfills and leachate treatment/storage ponds can adequately manage/contain these materials. Of particular importance is the understanding of how engineered nanomaterials may interact with the geosynthetics present in the liners. This work will elucidate the impact of engineered nanomaterials on high-density polyethylene geomembranes and importantly, how they may influence geomembrane durability/service lives. This research is transformative in that it is the first study in which engineered nanomaterial-high-density polyethylene liner interactions will be explored. Results will provide necessary information to assess whether current solid waste management processes are adequate to safely manage/contain such wastes. The research results will be widely disseminated via presentations and publications. This project is guided by the hypothesis that engineered nanomaterials will influence long-term stability of geomembranes by increasing antioxidant release/depletion. The nature of engineered nanomaterial influences on geomembranes are dependent on material application (e.g., landfill bottom liner or leachate storage pond) and environmental conditions (e.g., oxygen presence). The specific objectives of this work are: (1) Elucidate how selected engineered nanomaterials influence polymer oxidation, antioxidant diffusion, and subsequent changes in mechanical behavior of high-density polyethylene liners; (2) Understand how engineered nanomaterial surface chemistry influences polymer oxidation and antioxidant diffusion; and, (3) Perform molecular level simulations to calculate adsorption/partitioning coefficients, quantify diffusion coefficients, and calculate reaction kinetics for oxidation reactions, and develop a process model to quantify the effects of engineered nanomaterials on antioxidant depletion in high-density polyethylene liners. The PI is committed to promoting teaching, training, and learning while conducting this research. The broader impacts plan is comprised of three components: (1) K-12 outreach; (2) undergraduate research experiences for underrepresented populations in engineering; and, (3) doctoral student mentoring. It is anticipated that a large population of potential future engineers and scientists can be reached through these planned activities.