Collaborative Research: Overlooked Oxidation of Aqueous Alcohols: Kinetics, Mechanism, and Relevance to Water Reuse

在化学系环境化学科学项目的支持下，犹他大学的Emily Marron和南加州大学的Daniel McCurry及其学生将研究废水处理中发生的化学过程，特别是在水中添加氯以去除有害细菌和病毒时。然而，向废水中添加氯也会导致产生可能有毒的意外化学副产品。这个项目将描述氯与废水中存在的醇(如甲醇(木醇)和乙醇)反应生成甲醛和乙醛的反应，这些活性化合物可能具有有害的生物学特性，特别是在引入包括核酸和蛋白质在内的生物分子方面。了解醇和氯生产乙醛的化学过程对于最大限度地减少废水处理过程中这些化学物质的形成非常重要。面对气候变化和干旱，美国各地的社区缺乏可靠的饮用水来源。废水(污水)再利用是增加面临水资源紧张地区供水的一种选择。废水再利用涉及许多处理步骤，以确保水可以安全饮用。来自两所大学的本科生研究人员将为这项工作做出贡献，并通过社交媒体向科学界通报该项目的成果。在废水回用过程中，用臭氧或氯氧化来灭活病原体并转化化学污染物会形成有毒的低分子化合物，包括醛。虽然废水臭氧氧化产生的醛是众所周知的，但在氯化过程中的动力学、形成机理和潜在的前体在很大程度上是未知的。这个项目将研究一组被忽视的前体：醇的氯化反应生成醛的过程。初步实验表明，在与水处理相关的条件下，氯气可以将甲醇氧化为甲醛。在常规废水处理中，甲醇和乙醇等醇经常被用作补充碳源，并且很可能存在于水回用操作中。此外，醇通常用于环境化学研究中的原料溶液制备，假设它们相对于氯是惰性的。该项目的目标包括确定氯氧化水乙醇的动力学、产物和机理，开发一种新的定量复杂水基质中微量醇的方法，并将其应用于定量废水中的醇及其对观察到的醛形成的贡献。该奖项反映了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 in the Division of Chemistry, Emily Marron at the University of Utah and Daniel McCurry at the University of Southern California and their students will study chemical processes occurring in wastewater treatment, specifically, when chlorine is added to water to remove harmful bacteria and viruses. However, the addition of chlorine to wastewater also results in the production of unintended chemical byproducts that may be toxic. This project will characterize the reaction of chlorine with alcohols, such as methanol (wood alcohol) and ethanol, which are present in wastewater, to produce aldehydes, such as formaldehyde and acetaldehyde, reactive compounds that can have deleterious biological properties, particularly in adducting biomolecules, including nucleic acids and proteins. Understanding the chemistry of aldehyde production from alcohols and chlorine is important to minimize the formation of these chemicals during wastewater treatment. In the face of climate change and drought, communities across the United States lack reliable sources of drinking water. Re-using wastewater (sewage) is an option to increase water supply in areas facing water stress. Wastewater reuse involves many treatment steps to ensure the water is safe to drink. Undergraduate researchers from both institutions will contribute to the work and inform the scientific community about the project findings through social media.During wastewater reuse, oxidation with ozone or chlorine to inactivate pathogens and transform chemical contaminants can form toxic low molecular weight compounds including aldehydes. While aldehyde generation from ozonation of wastewater is well understood, the kinetics, mechanism of formation, and potential precursors during chlorination are largely unknown. This project will investigate the formation of aldehydes from the chlorination of an overlooked group of precursors: alcohols. Preliminary experiments have demonstrated that methanol can be oxidized to formaldehyde by chlorine under conditions relevant to water treatment. Alcohols such as methanol and ethanol are frequently used as a supplemental carbon source during conventional wastewater treatment, and are likely present in water reuse operations. Additionally, alcohols are routinely used in environmental chemical research for stock solution preparation under the assumption that they are inert with respect to chlorine. The goals of this project include determining the kinetics, products, and mechanism of aqueous alcohol oxidation by chlorine, the development of a new method for quantifying trace alcohols in complex aqueous matrices, and its application to quantify alcohols in wastewater effluent and their contribution to observed aldehyde formation.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.