Collaborative Research: Developing Novel Surface Immobilized Photocatalysts Using Functionalized C60

合作研究：使用功能化 C60 开发新型表面固定光催化剂

• 批准号: 0933219
• 负责人: Pedro Alvarez
• 金额: $ 20.02万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0933219&HistoricalAwards=false
• 关键词: Collaborative; Research; Developing; Novel; Surface

0933219/0932872Alvarez/KimIt is well known that C60 (buckminsterfullerene) and some of its functionalized derivatives can photochemically produce reactive oxygen species such as singlet oxygen and superoxide. This conversion of light energy to oxidizing power has been extensively studied and applied for photocatalytic organic synthesis and photodynamic therapy. Although fullerene-based photocatalysis is also a promising sustainable approach for water treatment, such aqueous phase applications have been limited by the difficulty to make C60 accessible to target pollutants in water, since pristine C60 is virtually nonwettable. Even if C60 is rendered water soluble (for example, by functional derivatization), it is challenging to prevent C60 release to product water and recycle it for prolonged use. The overarching objective of the proposed research is to overcome the above limitations and develop environmentally benign C60-based photocatalysts for water and wastewater treatment and reuse. They plan to achieve this goal by immobilizing photoactive form of C60 onto easily recoverable support materials via covalent bonding. Specific research objectives include: 1) developing new and enhancing existing methods to immobilize C60 and selected functionalized C60 onto support material surfaces; 2) quantifying their photochemical reactivity, mainly related to 1O2 production, as a function of support substrate and water chemistry; and 3) evaluating these novel photosensitizers for degradation of selected organic contaminants and inactivation of a representative microorganism. They hypothesize that: 1) chemical attachment of C60 and C60 derivatives to polymeric surface is achievable without any significant loss in photochemical activity for 1O2 production which originates from C60s cage structure; 2) C60 based catalyst will exhibit minimal reduction of photocatalytic activity after prolonged use due to the chemical stability of C60, and 3) immobilization via covalent bonding will minimize catalyst release to environment and enhance recycling. Validity of these hypotheses forms a foundation for developing an innovative C60-based photocatalysis process. This is a two-institution collaboration that brings together expertise in photoactive nanomaterial synthesis, fundamental photochemistry, and photocatalyst application for oxidative degradation of organic contaminants and inactivation of microorganisms. They will initially employ selected homogenized and immobilized forms of tetrakis- and hexakis-C60 adducts with carboxylic, hydroxyl, and amine moieties. Specific tasks include: 1) syntheses of water-soluble functionalized C60, C60(or derivatized C60)-coated beads, and C60 (or derivatized C60)-incorporated polymer; 2) characterization of photochemical properties of these materials with focus on kinetics and mechanisms of 1O2 production using wet-chemical method, electron spin resonance (ESR) trapping technique, and laser flash photolysis (LFP); and 3) kinetics and mechanistic studies on photocatalytic oxidation of selected organic pollutants and inactivation of representative microorganisms (bacteria and virus). This is one of the first attempts to apply fullerene-based photocatalysis in environmental engineering. They are motivated by the unique properties of C60, including 1) exceptional photocatalytic activity, 2) ability to use visible light for photoexcitation, and 3) chemical stability. Immobilization of C60 is conducive to prevention of secondary contamination and facilitating recycle and reuse, which will encourage further research on applications of fullerene-based photocatalysis. For example, surface immobilized C60 could be applied for antibacterial surface synthesis or air purification. Fundamental understanding gained on how the photocatalytic properties of fullerenes change upon attachment and bactericidal mechanisms will also be important to inform ecotoxicological risk assessment. Ensuring access to inexpensive and clean sources of water is one of the greatest global challenges of this century. Nanotechnology offers opportunities to leapfrog over traditional infrastructure-intensive technologies to develop more sustainable approaches for water management. This project has a great potential to develop safe, easy to implement, and reusable C60-based photocatalysts that require only sunlight for water remediation and reuse. Results will be broadly disseminated in publications and integrated into undergraduate and graduate courses. They will also train students in an emerging area where qualified professionals are in short supply. These students will gain interdisciplinary and collaborative experience with applications of nanochemistry, photochemistry and environmental engineering.

0933219/0932872 Alvarez/Kim众所周知，C60（巴克敏斯特富勒烯）及其一些官能化衍生物可以光化学地产生活性氧物质，例如单线态氧和超氧化物。这种将光能转化为氧化能力的过程已经被广泛研究并应用于光催化有机合成和光动力治疗。虽然基于富勒烯的C60也是一种有前途的水处理可持续方法，但这种水相应用受到难以使C60接近水中目标污染物的限制，因为原始C60几乎是不可降解的。即使C60是水溶性的（例如，通过功能性衍生化），也难以防止C60释放到产物水中并将其再循环用于长期使用。拟议研究的总体目标是克服上述限制，并开发环境友好的C60基光催化剂用于水和废水处理和再利用。他们计划通过共价键将光活性形式的C60固定在易于回收的载体材料上来实现这一目标。具体的研究目标包括：1）开发新的和增强现有的方法，以将C60和选择的官能化C60吸附到载体材料表面上; 2）量化它们的光化学反应性，主要与1 O2产生有关，作为载体基质和水化学的函数;和3）评价这些新型光敏剂对所选有机污染物的降解和对代表性微生物的灭活。他们假设：1）可实现C60和C60衍生物与聚合物表面的化学连接，而不会显著损失源自C60笼状结构的1 O2产生的光化学活性; 2）由于C60的化学稳定性，C60基催化剂在长期使用后将表现出最小的光催化活性降低，和3）通过共价键合的固定化将使催化剂释放到环境中最小化并提高再循环。这些假设的有效性形成了一个创新的C60为基础的加氢裂化过程的基础。这是一个两个机构的合作，汇集了光活性纳米材料合成，基础光化学和光催化剂应用的专业知识，用于有机污染物的氧化降解和微生物的灭活。他们将首先采用选定的均质化和固定化形式的四和六-C60加合物与羧基，羟基和胺部分。具体任务包括：1）水溶性官能化C60、C60（或衍生的C60）-包被的珠，和C60（或衍生的C60）-掺入的聚合物; 2）表征这些材料的光化学性质，重点是使用湿化学方法、电子自旋共振（ESR）捕获技术和激光闪光光解（LFP）产生1 O2的动力学和机制;（3）光催化氧化部分有机污染物的动力学和机理研究以及典型微生物（细菌和病毒）的灭活研究。这是首次尝试将富勒烯基纳米材料应用于环境工程。它们的动机是C60的独特性质，包括1）卓越的光催化活性，2）使用可见光进行光激发的能力，以及3）化学稳定性。C60的固定化有利于防止二次污染，有利于回收和再利用，这将鼓励进一步研究富勒烯基碳纳米管的应用。例如，表面固定化的C60可用于抗菌表面合成或空气净化。对富勒烯的光催化性能如何在附着和杀菌机制上发生变化的基本理解对于生态毒理学风险评估也很重要。确保获得廉价和清洁的水源是本世纪最大的全球挑战之一。纳米技术提供了超越传统基础设施密集型技术的机会，以开发更可持续的水管理方法。该项目具有开发安全，易于实施和可重复使用的基于C60的光催化剂的巨大潜力，这些光催化剂只需要阳光即可用于水的修复和再利用。研究结果将在出版物中广泛传播，并纳入本科生和研究生课程。他们还将在一个合格专业人员短缺的新兴领域培训学生。这些学生将获得纳米化学，光化学和环境工程应用的跨学科和协作经验。