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

该奖项由化学部环境化学科学计划支持。凯斯西储大学的张惠春教授和丹尼尔·拉克斯教授及其学生研究了氧化锰（MnOx）与新兴污染物（EC）的反应。由于人类对废水流的投入，我们的溪流、河流、湖泊和海洋中出现了各种各样的新污染物--化合物。 新出现的令人担忧的污染物包括药品和个人护理产品、阻燃剂和杀虫剂。 需要进行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了去除EC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的使用是有希望的，因为这些化合物是天然氧化剂。许多合成MnOx在诸如能源生产和化学合成的应用中非常有用。只有一小部分天然丰富的MnOx化合物已被检查其在分解EC中的反应性。该项目研究了各种合成MnOx化合物在去除EC中的反应性。这项研究的结果可能会使更具成本效益的水处理技术，目标是在受污染的场地去除EC。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。项目研究结果被纳入本科和研究生课程，并广泛传播到不同背景的社区，包括专业人士以及公众。 本研究采用实验和计算相结合的方法，研究了MnOx直接氧化ECs和MnOx催化高锰酸盐氧化ECs的机理。首先合成一系列具有不同结构、Mn氧化态、孔隙率和掺杂剂的MnOx。然后，各种MnOx性能的实验，其特征在于，包括形态，结构，表面，电化学，组成和热力学性质。 其中一些化合物是理论上设计的。基于所观察到的MnOx作为氧化剂或催化剂的反应性，定量结构-活性关系被开发为MnOx性质的函数。最后，MnOx反应机制阐明使用多管齐下的方法。其中包括研究Mn（III）物种、晶格氧、Mn-O键和刘易斯酸位点的作用，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 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.