RUI: CAS-MNP: Molecular Behavior at Colloidal/Aqueous Interfaces of Heterogeneous Nano- and Micro-Plastics - Binding Interactions and Effect of Aging

在化学系环境化学科学项目的支持下，Mahamud Subir和他在鲍尔州立大学的研究生和本科生团队将进行表面选择性二次谐波发生（SHG）光谱和石英晶体微天平技术，目的是确定与各种类型的微和纳米塑料（MNP）有关的吸附参数。 塑料污染已成为一个主要的环境问题。在水生环境中，塑料可以分解并形成尺寸从几纳米到数百微米的小碎片。这些微米和纳米塑料（MNP）颗粒提供了大的表面积，这使得溶解在水中的其他有机污染物能够与MNP表面相互作用。 了解这些结合的相互作用是很重要的，因为它们决定了MNP和有机污染物的命运和运输特性。此外，阐明MNP的表面亲和力对于开发有效的吸附技术以去除微塑料至关重要。在本项目中，将研究不同类型的有机化合物与各种组成和表面性质的MNP的表面相互作用。该项目不仅将产生关于MNP在有机分子存在下的结合行为的新知识，还将培训未来的科学家应对与塑料污染相关的持续挑战。 MNP是多相的，它们的界面化学是复杂的。因此，使用表面选择性二次谐波发生（SHG）光谱和石英晶体微天平技术进行系统的调查，以确定有关的吸附热力学和动力学参数的各种类型的MNP。将使用带电和中性SHG探针分子进行吸附研究。温度依赖性的吸附研究，预计将揭示其与MNP/水界面的相互作用的结合强度和机制。总之，这些实验有可能帮助建立MNP的表面官能团和结合相互作用之间的关系。将检查非特异性与特异性结合相互作用的作用。其他目标包括调查MNP老化及其大小和形状对分子结合的影响。确定有机化合物的吸附强度和MNP的化学特性之间的相关性有潜力，从长远来看，预计将提供一个基础，为改善建模的命运和运输这些新兴的水生污染物。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

With support from the Environmental Chemical Sciences Program in the Division of Chemistry, Mahamud Subir and his team of graduate and undergraduate students at Ball State University will perform surface-selective second harmonic generation (SHG) spectroscopy and quartz crystal microbalance technology with the aim of determining the adsorption parameters pertaining to various types of micro- and nano-plastics (MNPs). Plastic pollution has become a major environmental concern. In the aquatic environment, plastics can break down and form small fragments ranging from a few nanometers to hundreds of micrometers in size. These micro- and nano-plastic (MNP) particles offer a large surface area, which allows other organic contaminants dissolved in water, to interact with the MNP surfaces. Understanding these binding interactions is important as they determine the fate and transport properties of both MNPs and organic pollutants. Moreover, elucidating the surface affinities of MNPs is critical in developing effective adsorption techniques to remove microplastics. In this project, surface interactions of different types of organic compounds with MNPs of various compositions and surface properties will be investigated. The project will not only generate new knowledge on the binding behavior of MNPs in the presence of organic molecules, but also train future scientists in tackling persistent challenges associated with plastics pollution. MNPs are heterogeneous and their interfacial chemistry is complex. Therefore, a systematic investigation using surface-selective second harmonic generation (SHG) spectroscopy and quartz crystal microbalance technology will be performed to determine the adsorption thermodynamic and kinetic parameters pertaining to various types of MNPs. The adsorption studies will be conducted using charged and neutral SHG probe molecules. Temperature-dependent adsorption studies are expected to reveal the binding strengths and mechanisms of their interaction with MNP/aqueous interfaces. Together, these experiments have the potential to help establish relationships between surface functional groups of MNPs and binding interactions. The role of non-specific vs. specific binding interactions will be examined. Additional objectives include investigating the impact of MNP ageing and of their size and shape on molecular binding. Determining a correlation between organic compound adsorption strength and chemical characteristics of MNPs has the potential, in the longer term, is expected to provide a foundation for improved modeling of the fate and transport of these emerging aquatic contaminants.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.