CAS-MNP: Evaluating Degradation Products and Changes in Colloidal Properties of Microplastics During Photochemical Weathering

该奖项由美国国家科学基金会化学部的环境化学科学（ECS）项目支持。威斯康星大学密尔沃基分校淡水科学学院的郭老东教授和他的学生将研究微塑料/微纤维在水生环境中的风化。动力学，产品和这些降解过程的机制将被确定。微塑料和纳米塑料在水生环境中普遍存在，具有持久性和毒性，是公认的新兴污染物。纳米塑料被认为对生物体具有更高的毒性。该项目将通过研究生和本科生，特别是代表性不足的学生和本科生研究人员的参与，将研究、教育和推广结合起来，促进多学科合作研究，并加强对环境化学和淡水科学研究生和本科生的培训。微塑料是五大湖地区的一个重要问题，受到地方和州法规的越来越多的监管。项目团队将与相关的联邦/州机构、利益相关者和公众（包括K12学生）合作，分享关于微塑料在水生环境中的命运和运输及其对生态系统和人类健康的潜在影响的研究成果。尽管它们很重要，但人们对微纳米塑料（MNP）的基本环境化学、光化学反应、表面和胶体性质的变化以及风化过程和风化后的环境行为知之甚少。为了填补知识空白，项目团队将利用有代表性的微塑料和微纤维进行受控的实验室实验进行研究。微塑料的降解产物，包括溶解的有机分子和纳米塑料，将使用总有机碳分析仪和紫外可见和荧光光谱来表征化学和光学性质。利用动态光散射技术和不对称流场-流分选耦合多角度光散射检测器，将确定表面和胶体性质的变化，如ζ势和流体动力学尺寸分布。此外，傅里叶变换红外光谱和微拉曼光谱将用于表征塑料聚合物和官能团。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 is supported by the Environmental Chemical Sciences (ECS) Program in the NSF Division of Chemistry. Professor Laodong Guo and his students in the School of Freshwater Sciences at University of Wisconsin-Milwaukee will study the weathering of microplastics / microfibers in aquatic environments. The kinetics, products, and mechanisms of these degradation processes will be determined. Microplastics and nanoplastics are ubiquitous, persistent, and toxic in aquatic environments and have been recognized as emerging contaminants. Nanoplastics are believed to have higher toxicity to organisms. The project will integrate research, education, and outreach through the participation of graduate and undergraduate students, especially underrepresented students and undergraduate research fellows, promote multidisciplinary collaborative research, and augment the training of graduate and undergraduate students in environmental chemistry and freshwater sciences. Microplastics are an important issue in the Great Lakes Region and subject increasing regulation by local and state ordinances. The project team will work with relevant federal/state agencies, stakeholders, and the general public, including K12 students, to share research findings on the fate and transport of microplastics in aquatic environments and their potential impacts on ecosystem and human health.Despite their importance, little is known about the fundamental environmental chemistry of micro- and nano-plastics (MNP), photochemical reactivities, and changes in their surface and colloidal properties and environmental behavior during and after weathering. To fill the knowledge gap, the project team will conduct research using controlled laboratory experiments on representative microplastics and microfibers. The degradation products from microplasics, including dissolved organic molecules and nanoplastics, will be characterized for chemical and optical properties using total organic carbon analyzer and ultraviolet-visible and fluorescence spectroscopy. Changes in surface and colloidal properties, such as zeta-potential and hydrodynamic size-distribution, will be determined using dynamic light scattering technique and asymmetrical flow field-flow fractionation coupled with multiple angles light scattering detectors. In addition, Fourier-transform infrared spectroscopy and Micro-Raman spectroscopy will be used to characterize plastic polymers and functional groups.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.