RUI: Adsorption and Surface Mediated Photo-Degradation Rate of Contaminants on Colloidal Natural Organic Matter

在化学系环境化学科学项目的支持下，鲍尔州立大学的马哈穆德·苏比尔博士和他的学生探索了天然有机物(NOM)对新兴污染物(ECs)的迁移和去向的影响。ECS，如药物和内分泌干扰物，通常在水环境中被检测到。NOM是悬浮在环境水域中的颗粒，由碳基分子组成。NOM在水污染物的分布和转化中发挥作用，但具体如何以及在多大程度上仍不清楚。这项研究的重点是发现NOM颗粒大小和表面成分对有机污染物的吸收和光化学分解的影响。这些项目为本科生提供了一个进行动手实验的独特机会。这项研究创建了关于污染物分子和NOM的结合强度的信息，以及由NOM表面介导的反应速率。这些发现有助于解释ECs对我们的生态系统和我们的健康的影响。这项研究在纳米、表面和环境化学领域使用了传统和先进的激光光谱工具。二次谐波产生(SHG)和其他分析技术将有机污染物的表面效应从整体溶液相光化学中分离出来。该项目使用不同组成的腐殖质物质开发模型胶体名称。测量了不同ECs与模型表面的结合亲和力。测定了化学吸附分子和物理吸附分子在非水界面上的光解速率。此外，该项目还调查了NOM大小、溶液酸度和反应性羟基自由基的存在对感兴趣的过程的影响。这些结果有望产生一个广泛的吸附平衡和光动力学参数目录。它们还提供了对特定EC-NOM表面相互作用的性质的基本洞察。这些知识可能有助于制定补救方法。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Environmental Chemical Sciences Program of the Chemistry Division, Dr. Mahamud Subir and his students at Ball State University explore the influence of Natural Organic Matter (NOM) on the transport and fate of emerging contaminants (ECs). ECs, such as pharmaceuticals and endocrine disruptors, are commonly detected in aquatic environments. NOM are particles suspended in environmental waters that consist of carbon-based molecules. NOM plays a role in aquatic pollutant distribution and transformation, but exactly how and to what extent remains unclear. This study focuses on finding the effect of NOM particle size and surface constituents on the uptake and photochemical breakdown of organic contaminants. The projects provide undergraduate students with a unique opportunity to perform hands-on experiments. The study creates information about binding strength of the contaminant molecules and NOM, and the rates of reactions that are mediated by the NOM surfaces. These findings help to explain the impact of ECs on our ecosystem and our health. This study uses both traditional and advanced laser spectroscopic tools in the areas of nano-, surface, and environmental chemistry. Second Harmonic Generation (SHG) and other analysis techniques isolate the surface effect from the bulk solution phase photochemistry of organic pollutants. The project develops model colloidal NOM using humic substances of distinct composition. The binding affinities of various ECs to the model NOM surfaces are measured. The rate of photolysis of both chemi- and physi-sorbed molecules at the NOM-aqueous interface is determined. In addition, the project investigates the influence of NOM size, solution acidity, and presence of reactive hydroxyl radicals on the processes of interest. These results are expected to yield an extensive catalogue of adsorption equilibrium and photo-kinetic parameters. They also provide fundamental insight into the nature of specific EC-NOM surface interactions. This knowledge can potentially assist in developing remediation methodologies.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.