Collaborative Research: CAS-MNP: Understand and Predict the Adsorption of Organic Contaminants by Aging Microplastics

该奖项由化学系环境化学科学项目颁发，支持亚利桑那州立大学的Francois Perreault教授和Jay Oswald教授以及缅因大学的Onur Apul教授对微塑料的研究。这些小塑料颗粒是在废塑料分解过程中形成的。由于它们的体积小，微塑料比大塑料片在表面积累了更多的有机污染物。微塑料在环境中由于阳光或微生物的作用而老化，这改变了它们的表面特性。为了预测微塑料对环境的影响，了解微塑料在阳光或微生物作用下的老化如何影响污染物的吸附是很重要的。这个项目的重点是低密度聚乙烯的老化，这是最丰富的塑料之一。该项目的探索性范围为未来深入研究微塑料老化的性质及其在复杂自然系统中的影响提供了见解。两所院校的研究生和本科生都有机会学习跨学科研究，包括实验和理论工作。该团队还在其社区为K-12学生开展适合年龄的塑料污染主题外展活动。本项目结合实验和理论方法，以确定有机污染物在原始和老化低密度聚乙烯微塑料上吸附的分子水平机制。基于实验室的老化程序，模拟阳光或表面生物膜的影响，用于生产具有良好特征的低密度聚乙烯微颗粒，代表环境微塑料。利用这些模型微塑料，测量了一系列模型有机污染物的吸附等温线，以确定生物膜或表面化学的变化如何影响不同类别污染物的吸附。在老化微塑料表征的基础上，利用分子动力学模拟来识别环境老化过程中发生的表面化学分子水平的变化。这种多学科的方法提供了一个机制的见解，如何通过阳光或生物膜的环境老化影响微塑料在环境中作为有机污染物载体的作用。本项目开发的实验框架可以应用于广泛的微塑料材料或环境老化机制，以全面了解有机污染物如何随着时间的推移与环境中的微塑料相互作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award from the Environmental Chemical Sciences Program in the Division of Chemistry supports Professors Francois Perreault and Jay Oswald at Arizona State University and Professor Onur Apul at the University of Maine for research on microplastics. These small plastic particles form during the breakdown of waste plastic. Because of their small size, microplastics accumulate more organic contaminants on their surface than larger plastic pieces. Microplastics age in the environment due to the action of sunlight or microorganisms, which changes their surface characteristics. To predict the environmental effects of microplastics, it is important to understand how aging of microplastics by sunlight or microorganisms affect contaminant adsorption. This project focuses on the aging of low-density polyethylene, one of the most abundant plastics. The exploratory scope of this project leads to insights for future in-depth studies of the nature of microplastics aging and their effect in complex natural systems. Graduate and undergraduate students at the two institutions have the opportunity to learn about interdisciplinary research, including experimental and theoretical work. The team also engages in age-appropriate outreach activities on the topic of plastic pollution for K-12 students in their communities. This project combines experimental and theoretical approaches to identify the molecular-level mechanisms involved in organic contaminant adsorption on pristine and aged low-density polyethylene microplastics. Laboratory-based aging procedures, simulating the effect of sunlight or surface biofilms, are used to produce well-characterized low-density polyethylene microparticles representative of environmental microplastics. Using these model microplastics, adsorption isotherms are measured for a range of model organic contaminants to determine how biofilms or the change in surface chemistry affect the adsorption of different classes of contaminant. Molecular dynamics simulations are used to identify, based on the aged microplastics characterization, the molecular-level changes in surface chemistry that occur during environmental aging. This multidisciplinary approach provides a mechanistic insight into how environmental aging by sunlight or biofilms affect the role of microplastics as vectors of organic contaminants in the environment. The experimental framework developed in this project can be applied to a wide range of microplastic materials or mechanism of environmental aging to provide a comprehensive understanding of how organic contaminants will interact with microplastics in the environment over time.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.