Engineered Applications of Carbon Nanotubes in Reverse Osmosis Membranes

水的数量和质量的下降加速了海水淡化作为一种可靠的饮用水来源的采用。然而，基于膜的海水淡化技术的广泛实施受到高能量需求的限制。一个基本的重新设计的反渗透（RO）膜将需要在一个能源有限的环境中满足水资源的需求。提出的研究的总体目标是通过增加膜渗透性和减少污染来减少膜基脱盐的能源需求。本项目利用碳纳米管（CNTs）的独特特性，设计具有高通量和抗生物污染的新型反渗透膜。第一个目标是通过在薄膜屏障中加入单壁碳纳米管（SWNTs）来提高传统薄膜复合材料（TFC）反渗透膜的渗透性并减少生物污染。他们假设单壁碳纳米管会扰乱薄膜聚酰胺层的聚合物填充结构，从而提高传统TFC膜的渗透性。单壁碳纳米管的抗菌特性也为防止膜生物污染提供了新的策略。本研究将优化SWNT在TFC反渗透膜中的掺入，评估SWNT对膜通透性和选择性的影响，量化SWNT-TFC膜表面的微生物失活，并阐明其通透性增强和细菌细胞毒性的机制途径。提出的研究的第二个目标是制造一个排列的SWNT膜。理论预测通过排列的碳纳米管膜具有高通量和高阻盐性，但目前的制造技术无法通过尺寸排斥机制生产出符合脱盐理论要求的膜。用液晶剂对单壁碳纳米管进行合成后排列，将得到一种直径足够小的膜，可以拒绝水合盐离子。他们的研究将涉及SWNT的制备和表征，液晶系统的优化和表征，SWNT排列的演示，排列的SWNT膜的表征以及膜孔隙率的优化。该研究将为制备具有高渗透性和低生物污染倾向的坚固反渗透膜奠定科学基础。这些下一代反渗透膜将大大减少海水淡化的能源使用和成本，从而为通过海水淡化增加和多样化全球供水提供了可行的途径。从这项研究中获得的知识可以很容易地应用于高选择性碳纳米管超滤和纳滤膜的开发，这些超滤和纳滤膜可用于生物医学，化学，分析和环境分离过程。申请的大部分资金将用于培养一个新兴的跨学科研究课题的博士生。学生将有机会担任新开发的聚合物物理课程的助教，该课程以实验技术为特色，在拟议的工作中大量使用实验技术。此外，两名本科生将进行他们的高级论文研究作为这个项目的一部分。PI和co-PI都致力于招募科学界代表性不足的群体，并将在本项目中进一步实现这一目标。这项工作将作为高中科学项目设计和实施的基础，作为纽黑文学生科学博览会和科学教师研究经验（REScT）计划的一部分。至关重要的是，这些推广工作促进了K-12科学教育，提高了人们对水质和环境问题的认识。除了研究和教育效益之外，拟议的工作还具有深远、切实的社会影响的潜力，因为它直接涉及科学的进步和技术的发展，以解决一个紧迫的问题。

PI: Chinedum OsujiProposal Number: 1133484Decline in water quantity and quality has accelerated the adoption of desalination as a reliable source of potable water. Widespread implementation of membrane-based desalination technologies, however, is constrained by the high energy requirement. A fundamental redesign of reverse osmosis (RO) membranes will be needed to meet water resource needs in an energy constrained environment. The overarching aim of the proposed research is to reduce the energy demands of membrane-based desalination by increasing membrane permeability and reducing fouling. This project exploits the unique properties of carbon nanotubes (CNTs) in the design of novel RO membranes with high flux and resistance to biofouling. The first objective is to improve permeability and reduce biofouling of conventional thin-film composite (TFC) RO membranes by incorporating single-walled carbon nanotubes (SWNTs) into the thin-film barrier. They hypothesize that SWNTs will perturb the polymer packing structure of the thin-film polyamide layer, thereby enhancing the permeability of conventional TFC membranes. The antimicrobial characteristics of SWNTs also offer novel strategies for the prevention of membrane biofouling. The proposed research will optimize SWNT incorporation into TFC RO membranes, evaluate the impact of SWNTs on membrane permeability and selectivity, quantify microbial inactivation at the SWNT-TFC membrane surface, and elucidate the mechanistic pathways for permeability enhancement and bacterial cytotoxicity. The second objective of the proposed research is to fabricate an aligned SWNT membrane. Theory predicts high flux and high salt rejection through aligned CNT membranes, but current fabrication techniques cannot produce membranes that meet theoretical requirements for desalination through a size exclusion mechanism. Post-synthesis alignment of SWNTs using liquid crystalline agents will yield a membrane with SWNT diameters small enough to reject hydrated salt ions. Their research will involve the preparation and characterization of SWNTs, optimization and characterization of the liquid crystalline system, demonstration of SWNT alignment, characterization of aligned SWNT membranes, and optimization of membrane porosity.The proposed research will develop the scientific base for the fabrication of robust RO membranes with high permeability and reduced biofouling propensity. These next generation RO membranes will substantially reduce the energy use and cost of desalination, thereby providing a viable avenue for augmenting and diversifying global water supplies via seawater desalination. Knowledge gained from this research can be readily applied to the development of highly selective carbon nanotube-based ultrafiltration and nanofiltration membranes that can be used in biomedical, chemical, analytical, and environmental separation processes.The majority of requested funds will be applied toward the training of a doctoral student on an emerging and interdisciplinary research topic. The student will have the opportunity to serve as a TA on a newly developed Polymer Physics course that features a lab module on experimental techniques heavily utilized in the proposed work. Additionally, two undergraduate students will carry out their senior theses research as part of this project. Both the PI and co-PI are committed to recruitment of underrepresented groups in science and will further that goal in this project. The proposed work will be used as the basis for the design and implementation of high school science projects, as part of the New Haven Science Fair for students and a Research Experience for Science Teachers (REScT) program. Critically, these outreach efforts advance K-12 science education and increase awareness of water quality and environmental issues. Beyond the research and educational benefits, the proposed work has the potential for profound, tangible societal impact, as it directly addresses the advancement of science and development of technology to tackle a pressing concern.