EAGER: CAS-MNP: Understanding the Dispersibility of Aging Micro/Nanoplastics

点击翻译按钮获取中文摘要

This award from the NSF Chemistry Division supports Professor Bhuvnesh Bharti and Professor Kalliat T. Valsaraj of Louisiana State University to study micro/nanoplastics. Micro/nanoplastics have become very common in the environment because of the gradual aging and weathering of discarded plastic waste. They can move up the food chain and potentially impact both aquatic and terrestrial species. In order to assess the potential health risks of micro/nanoplastics, it is critical to understand how they interact with an aqueous environment. The team studies the effect of sunlight-induced oxidation and aging of micro/nanoplastics which increases their wettability and ability to disperse in water. This project is exploratory with risk but the knowledge gained helps guide future in-depth studies of the environmental transport and fate of microplastics. The project provides opportunities for graduate students to develop new skills in an emerging field and actively engages undergraduate students from Baton Rouge Community College in the proposed research. This project addresses the question: Do micro/nanoplastics exist as micro or nanosized particles or do they aggregate into larger structures? This question is critical because any biological, environmental, and atmospheric impact of the micro/nanoplastics will be governed by their dispersed/aggregated state. Photooxidation processes lead to the formation of hydrophilic chemical functional groups on the surface of a degrading polymer, which increases the water wettability and dispersibility of the micro/nanoplastics. The team investigates the effect of photooxidation and solvent pH/ionic strength on the dispersibility of spherical shaped model micro/nanoplastics made from polyethylene, polypropylene, and polystyrene. These model plastics are photooxidized under controlled laboratory conditions and characterized for their dispersed state using a combination of small angle scattering, light microscopy, and spectroscopic techniques. This is important for understanding the potential of micro/nanoplastics to be transported into the atmosphere by incorporation into aqueous aerosol droplets such as fog, smog, and mist.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.