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: 0932872
• 负责人: Jaehong Kim
• 金额: $ 15.97万
• 依托单位: Georgia Tech Research Corporation
• 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 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0932872&HistoricalAwards=false
• 关键词: Collaborative; Research; Developing; Novel; Surface

0933219/0932872 Alvarez/Kim It 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（Buckminsterfullerene）及其某些功能化衍生物可以光化学上产生活力的活性氧，例如单线氧和超氧化物。光能向氧化能力的转化已得到广泛研究，并用于光催化有机合成和光动力疗法。尽管基于富勒烯的光催化也是水处理的有前途的可持续方法，但这种水相应用受到使C60在水中使用C60的困难的限制，因为原始C60实际上是不可填充的。即使将C60溶解（例如，通过功能性衍生化），防止C60释放到产品水并将其回收以进行长时间使用，这是一项挑战。拟议的研究的总体目标是克服上述局限性，并开发出基于C60的环保光催化剂，用于水和废水处理和再利用。他们计划通过将C60的光活性形式固定在可恢复的支持材料上，以实现这一目标。特定的研究目标包括：1）开发新的和增强现有方法，以将C60固定并选定的功能化C60固定在支持材料表面上； 2）量化其光化学反应性，主要与1O2产生有关，这是支持底物和水化学的函数； 3）评估这些新型的光敏剂，以降解选定的有机污染物和代表性微生物的失活。他们假设：1）可以实现C60和C60衍生物在聚合物表面的化学附着，而没有任何源自C60S笼式结构的1O2产生的光化学活性的显着损失； 2）基于C60的催化剂将由于C60的化学稳定性而长时间使用后，光催化活性的降低最少，3）通过共价键合固定将最大程度地减少对环境的催化剂释放并增强回收。这些假设的有效性为开发创新的基于C60的光催化过程构成了基础。这是一种两机构的合作，它汇集了光活性纳米材料合成，基本光化学和光催化剂的氧化降解和微生物失活的氧化降解的应用。他们最初将使用羧基，羟基和胺基部分采用选定的均质和固定形式的四基甲基和六基木C60加合物。特定任务包括：1）水溶性功能化的C60，C60（或衍生化的C60）涂层珠的合成和C60（或衍生化的C60）合并的聚合物； 2）使用湿化学方法，电子自旋共振（ESR）捕获技术和激光闪光照射（LFP），使用这些材料的光化学特性，侧重于1O2生产的动力学和机制； 3）关于选定有机污染物的光催化氧化以及代表性微生物（细菌和病毒）失活的动力学和机械研究。这是在环境工程中应用基于富勒烯的光催化的首批尝试之一。它们是由C60的独特特性的动机，包括1）特殊的光催化活性，2）使用可见光进行光激发和3）化学稳定性的能力。 C60的固定化有利于预防继发污染并促进回收和再利用，这将鼓励对基于富勒烯的光催化应用的进一步研究。例如，固定的C60表面可用于抗菌表面合成或空气纯化。关于在依恋和杀菌机制时如何变化的光催化特性如何获得的基本理解对于为生态毒理学风险评估提供信息也很重要。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。纳米技术提供了机会，可以超越传统的基础设施密集型技术，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，这些光催化剂仅需要阳光以进行水修复和再利用。结果将在出版物中广泛传播，并融入本科和研究生课程中。他们还将在新兴领域培训学生，那里有合格的专业人员供不应求。这些学生将在纳米化学，光化学和环境工程的应用中获得跨学科和协作的经验。