Rational Design of High-Purity Carbon Nanotube Dispersions Through Acute and Full Life-CycleToxicity Studies

提案题目：通过急性和全生命周期毒性研究的高纯度碳纳米管分散体的合理设计首席研究员：Kirk Ziegler机构：佛罗里达大学提案号：CBET- 0853347该奖项由2009年美国复苏和再投资法案（公法111-5）资助。单壁碳纳米管（SWNTs）产量的急剧增加以及SWNTs在商业和工业应用中的广泛应用表明，这些制造的纳米材料将不可避免地进入包括生物圈在内的环境。此外，由于目前尚不清楚swnt对环境和人类健康的影响，人们越来越关注。除了所有纳米材料共同的毒性问题外，swcnts的环境和人类健康影响还因杂质的存在而变得复杂，例如过渡金属催化剂和聚集状态。这些问题也是大多数SWNT应用程序中需要解决的重要问题。在不影响碳纳米管独特的尺寸相关特性（如强度、弹性、高吸附容量和可控电导率）的情况下，净化和分散碳纳米管仍然存在挑战。未来纳米管的应用将受到限制，除非开发出新的方法来克服这些问题，而不影响纳米管的独特性质。他们的长期目标是开发稳定的、高纯度的、基于大规模工艺的SWNT分散体，最大限度地减少对环境和人类健康的风险。他们假设，通过在生产过程中进行毒性测试和制造的密切耦合，可以减少或消除工程swnt对环境和人类健康的影响。无害环境的制造是新兴纳米材料工业的一个重要目标，确保对人类健康和环境的风险降到最低。事实上，纳米管加工有巨大的机会发展成为一个“绿色”的过程，受益于以往工业企业的经验。为了验证这一假设，工程学、化学和毒理学将被整合到一个先发制人的实验方法中。如有必要，毒性评估将要求改进SWNT净化和分散过程，以减少其潜在危害。这种新颖的反馈特征与在以下每个关键生产步骤后评估所生产的swcnts的毒性测试密切相关：(1)合成和干粉生产（基线毒性）；(2)净化;(3)分散。这项工作可能提供一种净化工艺，可以实现高纯度和高产量的单壁碳纳米管，而不会对管状结构造成损害，同时最大限度地降低对环境的风险。除了开发环境友好型制造工艺的好处之外，这项工作将使纳米管应用能够影响能源技术、材料科学、纳米电子、生物纳米技术和医疗领域，并加速纳米管的应用。杜邦公司和美国环境保护协会最近建立了一个框架，鼓励在纳米材料的设计阶段对毒性效应进行评估，以便开发新的、对环境友好的工艺。这一项目的成功完成将有助于确定SWNT扩散影响水生生物的机制。预计这些基本信息将有助于减少/消除碳纳米管的潜在负面影响。该项目的另一个目标是传播从这项研究中吸取的经验教训，并制定针对本科生的教育计划，特别是来自代表性不足的群体的教育计划。纳米技术是21世纪科学家和工程师研究的新领域。NSF估计将需要200万工人来支持未来纳米技术工业的需求。然而，科学、技术、工程和数学（STEM）学位的美国学生人数不断减少，这使得准备所需的劳动力变得具有挑战性。项目主管部门目前正在为一系列两门本科课程开发模块，旨在将纳米技术及其环境、社会和健康影响纳入当前的本科课程。因此，这些课程将被用作一种工具，将他们令人兴奋的研究成果整合到新的教育材料中。

Proposal Title: Rational Design of High-Purity Carbon Nanotube Dispersions through Acute and Full Life-Cycle Toxicity Studies Principal Investigator: Kirk Ziegler Institution: University of FloridaProposal No: CBET- 0853347 This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The dramatic increase in production rates of single-walled carbon nanotubes (SWNTs) and the anticipated widespread use of SWNTs in commercial and industrial applications suggest that these manufactured nanomaterials will inevitably enter the environment including the biosphere. In addition, there is a growing concern because of the currently unknown environmental and human health impacts of SWNTs. Besides the toxicity issues common to all nanomaterials, the environmental and human health implications of SWNTs are complicated by the presence of impurities, such as the transition metal catalyst, and aggregation state. These issues are also important problems to resolve in most SWNT applications. Challenges still remain in purifying and dispersing SWNTs without detrimentally affecting the unique size-related characteristics such as strength, elasticity, high adsorption capacity, and controllable conductivity. Future applications of nanotubes will be limited unless new approaches are developed to overcome these issues without impacting the unique properties of SWNTs. Their long term goal is to develop stable, high-purity, SWNT dispersions based on large-scale processes that minimize the risks to the environment and human health. They hypothesize that the environmental and human health impacts of engineered SWNTs can be reduced or eliminated through intimate coupling of toxicity testing and manufacturing during the production process. Environmentally benign manufacturing is an important goal for the emerging nanomaterial industries, ensuring that risks to human health and the environment are minimal. Indeed, nanotube processing has a tremendous opportunity to evolve as a "green" process, benefiting from the experience of previous industrial enterprises. To test the hypothesis, engineering, chemistry, and toxicology will be integrated into a preemptive experimental approach. If necessary, toxicity assessments will dictate refinement of the SWNT purification and dispersion processes to reduce their potential hazard. This novel feedback feature intimately couples manufacturing with toxicity tests of produced SWNTs evaluated after each of the following key production steps: (1) synthesis and dry powder production (baseline toxicity); (2) purification; and (3) dispersion. This work may provide a purification process which can achieve high purities and high yields of SWNTs without causing damage to the tubular structures while simultaneously minimizing risks to the environment. Aside from the benefits of developing an environmental-friendly manufacturing process, this work will enable and accelerate nanotube applications impacting energy technologies, materials science, nanoelectronic, bionanotechnology, and medical fields.A recent framework established by DuPont and Environmental Defense encourages the evaluation of toxicity effects at the design stage of nanomaterials so new, environmental-friendly processes can be developed. The successful completion of this project will help identify the mechanisms by which SWNT dispersions affect aquatic organisms. It is expected that this fundamental information will help reduce/eliminate the potential negative impacts of SWNTs. An additional objective of this project is to disseminate the lessons learned from this research and develop an educational program targeting undergraduate students, especially from underrepresented groups. Nanotechnology is a new frontier for the scientists and engineers of the 21st century. NSF estimates that 2 million workers will be needed to support future nanotechnology industry needs. However, the decreasing enrollment of U.S. students in science, technology, engineering, and mathematics (STEM) degrees make it challenging to prepare the needed workforce. The PIs are currently developing modules for a sequence of two undergraduate courses aimed at integrating nanotechnology and its environmental, societal, and health implications into the current undergraduate curricula. These courses will, therefore, be used as a vehicle to integrate their exciting research findings into new educational materials.