Collaborative Research: Degradation Mechanism of Cyanotoxins Using Novel Visible Light-Activated Titania (TiO2) Photocatlysts

合作研究：利用新型可见光激活二氧化钛 (TiO2) 光催化剂降解蓝藻毒素的机制

• 批准号: 1033458
• 负责人: Kevin O'Shea
• 金额: $ 15万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1033458&HistoricalAwards=false
• 关键词: Collaborative; Research; Degradation; Mechanism; Cyanotoxins

Collaborative Research: Degradation Mechanism of Cyanotoxins UsingNovel Visible Light-Activated Titania (TiO2) PhotocatalystsIntellectual merit: The increase of harmful algal blooms by cyanobacteria (Cyano-HABs) in estuaries and freshwater aquatic systems around the world is a major global problem. Cyano-HABs produce and release a variety of cyanobacterial toxins (cyanotoxins) (i.e., hepatotoxins, dermatotoxins, neurotoxins)with extremely high toxicity. The presence of high concentrations of harmful cyanotoxins in aquatic systems that serve or could potentially serve as sources of drinking water supply is a serious threat to human andenvironmental health. Conventional water treatment technologies are not wholly effective for the removal of these highly toxic naturally occurring toxic organic compounds and there is a critical need to develop new technologies which can effectively remove cyanotoxins from water. This proposal, submitted under the USIreland R&D initiative, aims to develop a solar driven advanced oxidation technology (AOT) as a viable solution to the problem of cyanotoxin contamination in water. Photocatalysis is an AOT which utilizes light-activatedsemiconductors to drive redox processes in water, leading to the destruction of organic pollutants and the inactivation of microorganisms. Titanium dioxide (TiO2) is the most suitable photocatalyst for water treatment; however, it requires UV excitation meaning that only 4% of the solar spectrum can be utilized.The development of visible light active (VLA) photocatalyst materials would be a major step forward towards the effective utilization of solar energy for the treatment of polluted water. Non-metal doped visible light activated (VLA) TiO2 materials are especially promising because they are strong visible-light absorbers and readily sensitize the formation of reactive oxygen species (ROS), which are known to degrade toxic organic pollutants. At present, the chemistry of organic substrates in the presence of irradiated VLA TiO2 is not well understood. This gap in the knowledge base is a critical problem, because it prevents the optimization of these systems for water treatment applications. The objective of this United States-Ireland trans-nationalcollaborative study, involving scientists and engineers from two universities in the United States (one being a minority institution), one University from Northern Ireland and one Institute of Technology from the Republic of Ireland, is to elucidate the mechanism of cyanotoxin degradation in water catalyzed by VLA TiO2 activated by visible light radiation or solar light. The central hypothesis is that irradiation of VLA TiO2 produces ROS that degrade cyanotoxins and that this reactivity can be readily modulated by varying the properties of the materials and the photocatalysis conditions. Guided by strong preliminary evidence and the extensive experience of the assembled researchers, this hypothesis will be tested by pursuing three specific objectives:(1) Synthesize, characterize and optimize new VLA TiO2 photocatalysts that will be evaluated for the destruction of cyanotoxins in water, (2) Investigate the photoelectrochemical response of VLA TiO2 photocatalysts, and (3) Determine the formation, fate, and reactivity of ROS generated during irradiation of VLA TiO2 in the presence of cyanotoxins, determine kinetics of cyanotoxin degradation, evaluate the biological activity of the oxidation products, and determine reaction intermediates and reaction pathways ofcyanotoxin degradation using VLA TiO2 photocatalyst activated by visible light radiation or solar light. The proposed work is original because it focuses on the preparation and photochemistry of new materials whose properties are readily modified. The proposed research is significant because it is expected to provide the mechanistic knowledge that is necessary for the development of rational strategies for optimizing solar-driven photocatalytic processes for water treatment.Broader impact: The research activities will directly advance discovery and understanding while promoting teaching, training and learning by bringing together a research team composed of undergraduate students, graduate students, postdoctoral researchers and the PIs. The research plan emphasizes participation of under-represented groups in scientific projects of international dimensions. In addition,undergraduate and graduate students will benefit from rigorous cross-disciplinary rotational laboratory training, thereby enriching the curriculum. The project will also offer opportunities to the student researchers to receive scientific training overseas, thereby facilitating exchange of ideas between the collaborating laboratories. In addition to this, the results of the research will be utilized for undergraduate and postgraduate taught courses (e.g. module in nanotechnology) in UC, FIU, UU, and CREST-DIT. Overall, the proposed activities are expected to strengthen co-operation between the institutes involved, and therefore,these activities are well aligned with the NSF?s international collaboration research objectives and the recent nanotechnology innovation agreement between the U.S., Republic of Ireland and Northern Ireland. The broader societal impacts of this research include enhancing sustainable development and shrinking the human ecological footprint. The knowledge obtained from these studies will guide the development of new water treatment methodologies using renewable energy. Application of these insights will accelerate the implementation of related nanotechnologies in addressing environmental problems, as well as advance the development of photoelectrochemical systems for solar energy harvesting and photocatalytic materials in other environmental applications such as air purification, disinfection and sensing.

合作研究：利用新型可见光活化二氧化钛（TiO 2）光催化剂降解蓝藻毒素的机理知识价值：在世界各地的河口和淡水水生系统中，蓝藻（Cyano-HABs）引起的有害藻华的增加是一个主要的全球性问题。蓝-有害藻酸盐产生和释放多种蓝细菌毒素（蓝毒素）（即，肝毒素、皮肤毒素、神经毒素）。作为或可能作为饮用水供应来源的水生系统中存在高浓度的有害蓝藻毒素，这对人类和环境的精神健康构成严重威胁。传统的水处理技术对于去除这些高毒性的天然存在的有毒有机化合物并不完全有效，并且迫切需要开发能够有效地从水中去除蓝藻毒素的新技术。该提案是在美国研发计划下提交的，旨在开发一种太阳能驱动的高级氧化技术（AOT），作为解决水中氰毒素污染问题的可行方案。光催化是一种AOT，它利用光激活的半导体来驱动水中的氧化还原过程，导致有机污染物的破坏和微生物的灭活。二氧化钛（TiO 2）是最适合用于水处理的光催化剂;然而，它需要紫外激发，这意味着只能利用4%的太阳光谱。可见光活性（VLA）光催化剂材料的开发将是有效利用太阳能处理污染水的重要一步。非金属掺杂的可见光激活（VLA）TiO 2材料特别有前途，因为它们是强可见光吸收剂并且容易敏化活性氧（ROS）的形成，已知活性氧（ROS）降解有毒有机污染物。目前，在辐照的VLA TiO 2的存在下的有机基板的化学没有很好地理解。知识库中的这种差距是一个关键问题，因为它阻止了这些系统在水处理应用中的优化。这项美国-爱尔兰跨国合作研究的目标是阐明可见光辐射或太阳光激活的VLA TiO 2催化水中蓝藻毒素降解的机制，研究涉及美国两所大学（其中一所为少数族裔机构）、北方爱尔兰一所大学和爱尔兰共和国一所理工学院的科学家和工程师。中心假设是VLA TiO 2的照射会产生可降解蓝藻的活性氧，并且这种反应性可以通过改变材料的性质和光催化条件来轻松调节。在强有力的初步证据和集合的研究人员的广泛经验的指导下，这一假设将通过追求三个具体目标进行测试：（1）合成、表征和优化新的VLA TiO 2光催化剂，其将被评估用于破坏水中的蓝藻毒素，（2）研究VLA TiO 2光催化剂的光电化学响应，以及（3）确定在蓝藻毒素存在下照射VLA TiO 2期间产生的ROS的形成、去向和反应性，确定蓝藻毒素降解的动力学，评估氧化产物的生物活性，并确定了可见光或太阳光活化VLA TiO 2光催化降解蓝藻毒素的反应中间体和反应途径。拟议的工作是原创的，因为它侧重于新材料的制备和光化学，其性质很容易修改。这项研究具有重要意义，因为它有望为优化太阳能光催化水处理工艺的合理策略提供必要的机理知识。研究活动将直接推进发现和理解，同时通过汇集由本科生，研究生，博士后研究人员和私家侦探。研究计划强调代表性不足的群体参与国际层面的科学项目。此外，本科生和研究生将受益于严格的跨学科旋转实验室培训，从而丰富了课程。该计划亦会为研究生提供机会，让他们到海外接受科学训练，从而促进合作实验室之间的意见交流。除此之外，研究结果还将用于UC，FIU，UU和CREST-DIT的本科和研究生课程（例如纳米技术模块）。总体而言，拟议的活动预计将加强有关机构之间的合作，因此，这些活动是很好地与国家科学基金？的国际合作研究目标以及美国、爱尔兰共和国和北方爱尔兰。这项研究的更广泛的社会影响包括加强可持续发展和缩小人类生态足迹。从这些研究中获得的知识将指导开发使用可再生能源的新水处理方法。这些见解的应用将加速相关纳米技术在解决环境问题方面的实施，并推动用于太阳能收集的光电化学系统和光催化材料在其他环境应用中的发展，如空气净化，消毒和传感。