Plasmon-Enhanced Catalytic Ozonation for Water Treatment and Reuse

1606117 Wu人口快速增长、淡水资源短缺、气候变化以及工业化和城市化导致的水源受损等压力对水处理技术提出了重大挑战。为了更好地确保高质量的饮用水，需要新的，创新的和具有成本效益的工艺。该项目可能是一个变革性的步骤，以加强催化臭氧化，销毁新出现的令人关切的污染物。高级氧化过程通常涉及羟基自由基的产生，并且可用于去除水和废水中的难降解有机污染物。然而，目前的高级氧化工艺通常是能量密集型的，并且可能形成不期望的副产物。该项目将研究一种增强的高级氧化工艺作为替代解决方案。本项目旨在研究一种创新的先进水处理工艺，包括等离子体增强催化臭氧化，以规避目前先进氧化工艺的局限性，这些工艺缺乏高能源效率和低副产物形成。当光子的频率（即照射光的波长）与表面电子的自然频率匹配时，发生局部表面等离子体共振，导致表面电子相对于正核背景的强烈振荡。等离子体金属（例如Ag、Au和Cu）支持表面等离子体激元极化激元，其中电磁波耦合到价电子的集体振荡。它通过增强半导体（例如TiO 2）中的光吸收并将等离子体激元能量从金属直接转移到金属氧化物载体以诱导电荷分离来提高太阳能转换效率。拟议的多学科研究代表了系统研究和利用先进的水/废水处理等离子体效应的第一次尝试之一。潜在的假设是，通过使用金属氧化物载体上的铜基催化剂（地球丰富的金属）的等离子体效应，可以以高得多的效率实现柠檬酸盐有机化合物的催化臭氧化，同时形成最少的副产物。用等离子体频率的光照射具有目标几何和等离子体性质的等离子体纳米颗粒将促进通过臭氧分解产生自由基物质，并导致有机污染物的更完全氧化（低有机副产物形成）。拟议的工作的结果将提供深入了解新的处理技术，工艺性能的数据，催化剂设计和合成的指导方针，以及通过先进的处理工艺的代表性新兴污染物的命运和转化的信息。使用LED（发光二极管）作为光源，这一创新过程可以很容易地在水处理中实施，特别是在臭氧用于消毒的情况下。它还可用于废水的深度处理，以直接/间接饮用水再利用。首要的假设是，通过使用金属氧化物载体上的铜基催化剂（地球丰富的金属）的等离子体效应，可以以高得多的效率以最少的副产物形成实现柠檬酸盐有机化合物的催化臭氧化。为了验证这一假设，PI将：（1）使用胶体化学合成和原子层沉积设计和合成具有目标几何结构和等离子体性质的铜基催化剂;（2）测试实验室等离子体增强催化臭氧化过程中的催化剂，重点关注矿化度、对溴酸盐形成的抑制以及催化剂的可重复使用性和稳定性;（3）确定催化剂的活性位点，研究反应机理;（4）将等离子体增强催化臭氧化应用于各种水基质，包括地表水、二级出水和水回用过程中产生的反渗透（RO）浓缩物。PI还制定了一个详细而全面的教育计划，涉及研究生和本科生，以及在实验室工作的高中生。

1606117WuThe stress of rapid population growth, shortage of fresh water sources, a changing climate, and impaired water sources due to industrialization and urbanization presents a major challenge to water treatment technologies. To better insure high quality drinking water, new, innovative, and cost effective processes are needed. This project is potentially a transformative step to enhance catalytic ozonation for the destruction of emerging contaminants of concern. Advanced oxidation processes usually involve generation of hydroxyl radicals and can be used to remove recalcitrant organic contaminants in water and wastewater. However, the current advanced oxidation processes are usually energy intensive and may form undesired byproducts. This project will examine an enhanced advanced oxidation process as an alternative solution. This project seeks to investigate an innovative advanced water treatment process involving plasmon-enhanced catalytic ozonation to circumvent the limitations of current advanced oxidation processes which fall short of high energy efficiency and low by-product formation. When the frequency of photons (i.e. wavelength of the irradiating light) matches the natural frequency of surface electrons, localized surface plasmon resonance occurs, resulting in strong oscillations of the surface electrons against the positive nuclei background. Plasmonic metals (e.g. Ag, Au, and Cu) support surface plasmon polariton where electromagnetic waves couple to the collective oscillations of valance electrons. It improves solar energy conversion efficiency by enhancing the light absorption in the semiconductor (e.g. TiO2) and directly transferring the plasmonic energy from the metal to the metal oxide support to induce the charge separation. The proposed multidisciplinary research represents one of the first attempts to systematically investigate and utilize the plasmonic effect in advanced water/wastewater treatment. The underlying hypothesis is that the catalytic ozonation of recalcitrant organic compounds can be achieved at a much higher efficiency with minimum by-products formation by using plasmonic effects of copper-based catalysts (earth abundant metal) on metal oxide supports. Irradiating plasmonic nanoparticles with targeted geometric and plasmonic properties with light at their plasmon frequency will facilitate the generation of radical species via ozone decomposition and lead to more complete oxidation of organic contaminants (low organic byproducts formation). The results of the proposed work will provide insights into the novel treatment technology, data for process performance, guidelines for catalyst design and synthesis, and information of fate and transformation of representative emerging contaminants through advanced treatment processes. With LEDs (light emitting diodes) as the light source, this innovative process can be easily implemented in water treatment especially where ozone is used for disinfection. It can also be used in advanced treatment of wastewater for direct/indirect potable reuse. The overarching hypothesis is, that the catalytic ozonation of recalcitrant organic compounds can be achieved at a much higher efficiency with minimum byproducts formation by using plasmonic effects of copper-based catalysts (earth abundant metal) on metal oxide supports. To test this hypothesis the PIs will: (1) Design and synthesize Cu-based catalysts with targeted geometric structure and plasmonic properties using colloidal chemical synthesis as well as atomic layer deposition; (2) Test the catalysts in laboratory plasmon-enhanced catalytic ozonation process focusing on the degree of mineralization, inhibition of bromate formation, and catalyst reusability and stability; (3) Identify the active sites of the catalysts investigate the reaction mechanisms; and, (4) Apply plasmon-enhanced catalytic ozonation in various water matrices including surface water, secondary effluent and reverse osmosis (RO) concentrate produced during water reuse. The PIs have also developed a detailed and comprehensive educational plan that involves graduate and undergraduate students, and high school students working in their laboratories.