Synthetic Manganese Oxides for Oxidative and Catalytic Removal of Contaminants of Emerging Concern

该奖项由化学系环境化学科学项目资助。凯斯西储大学的张惠春教授和Daniel Lks教授及其学生研究了氧化锰(MnOx)与新兴污染物(ECs)的反应。新出现的污染物种类繁多--由于人类进入废水流，我们的溪流、河流、湖泊和海洋中的化合物正在增加。新出现的关注污染物包括药品和个人护理产品、阻燃剂和杀虫剂。需要研究以确定这些化合物是否对人类、动物和/或植物生命有害。传统的水处理工艺并不是为去除ECs而设计的，它们的去除效率往往不足。在先进的处理技术中，MnOx的使用是有前景的，因为这些化合物是天然的氧化剂。许多人工合成的MnOx在能源生产和化学合成等应用中具有很高的实用价值。只有一小部分天然丰富的MnOx化合物被检测出它们在分解内皮细胞方面的反应活性。这个项目考察了各种合成的MnOx化合物在去除ECs方面的反应活性。这项研究的结果可能会使更具成本效益的水处理技术针对受污染地点的ECS去除。研究工作与教育和推广计划相结合，旨在让代表性不足的研究生、本科生和高中生参与研究。项目结果被纳入本科生和研究生课程，并广泛传播给具有不同背景的社区，包括专业人员和普通公众。本研究对保障人类和动植物的生命和健康具有重要意义。本研究采用实验和计算相结合的多方面方法，研究了高锰酸盐直接氧化和高锰酸盐和高锰酸盐催化氧化内皮细胞。首先合成了一系列具有不同结构、不同锰氧化态、不同孔隙率和不同掺杂的MnOx。然后，对MnOx的各种性质进行了实验表征，包括形态、结构、表面、电化学、组成和热力学性质。其中一些化合物是从理论上设计的。根据观察到的MnOx作为氧化剂或催化剂的反应活性，建立了作为MnOx性质的函数的定量结构-活性关系。最后，用多管齐下的方法阐明了MnOx反应的机理。其中包括研究Mn(III)物种、晶格氧、Mn-O键和Lewis酸位的作用，并进行动力学建模。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。

This award is supported by the Environmental Chemical Sciences Program of the Division of Chemistry. Professors Huichun Zhang and Daniel Lacks of Case Western Reserve University and their students study the reactions of manganese oxide (MnOx) with emerging contaminants (ECs). There is a large variety of emerging contaminants - compounds that are increasing in our streams, rivers, lakes and oceans due to human inputs into wastewater streams. Contaminants of emerging concern include pharmaceutical and personal care products, fire retardants, and pesticides. Research is needed to determine if these compounds are harmful to human, animal and/or plant life. Conventional water treatment processes were not designed to remove ECs and their removal efficiencies are often insufficient. Among advanced treatment technologies, the use of MnOx is promising because these compounds are natural oxidants. Numerous synthetic MnOx are highly useful in applications such as energy production and chemical synthesis. Only a small subset of naturally abundant MnOx compounds have been examined for their reactivity in breaking down ECs. This project examines the reactivity of a variety of synthetic MnOx compounds in removing ECs. The results of this research may enable more cost-effective water treatment technologies targeting ECs removal at contaminated sites. The research efforts are coupled with an educational and outreach plan designed to involve underrepresented graduate, undergraduate, and high school students in research. Project findings are integrated into the undergraduate and graduate curriculum, and broadly disseminated to communities with diverse backgrounds, including professionals as well as the general public. This research has important implications for safe-guarding human, animal and plant life and health.This research employs a multi-faceted approach combining experimental and computational tools to investigate oxidation of ECs either directly by MnOx or catalytically using permanganate with MnOx. A range of MnOx are first synthesized to have different structures, Mn oxidation states, porosity, and dopants. Then, a variety of MnOx properties are characterized experimentally, including morphological, structural, surface, electrochemical, compositional, and thermodynamic properties. Some of these compounds are designed theoretically. Based on the observed reactivity of MnOx as either an oxidant or a catalyst, quantitative structure-activity relationships are developed as a function of MnOx properties. Finally, MnOx reaction mechanisms are elucidated using multipronged approaches. These include examining the role of Mn(III) species, lattice oxygen, Mn-O bond, and Lewis acid sites, and conducting kinetic modeling.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.