Collaborative Research: A Bioinspired Approach towards Sustainable Membranes for Resilient Brine Treatment

许多水处理和工业过程产生大量的高盐度盐水，包括海水淡化，内陆咸水淡化以及通过水力压裂法生产石油和天然气。来自水淡化厂和石油/天然气生产威尔斯井的危险高盐度盐水的管理已成为全球环境挑战。膜蒸馏（MD）是一种用于处理高盐度盐水的有前途的技术，其可以减少需要处理的盐水的量，同时产生纯化的水渗透物以支持工业和农业用途。在过去的十年中，已经取得了显着的进展，朝着更有效的MD膜具有高润湿性和抗结垢性的高盐度盐水处理的发展。然而，这些膜通常通过用长链全氟烷基和多氟烷基物质（PFAS）改性它们的表面来制备，由于人们越来越关注它们在环境中的持久性、稳定性以及对人类和生物体的毒性，PFAS已成为优先污染物。该项目的总体目标是探索设计和制造的润湿和防垢MD膜盐水处理不使用PFAS。受跳虫对低表面张力液体的独特排斥性的启发，主要研究人员提出测试以下假设：具有高润湿性和高抗结垢性的有效MD膜可以通过将跳虫激发的supracolloidal结构共价连接到疏水平板膜的表面上来制造。该项目的成功完成将通过开发新的基础知识来指导无PFAS膜材料的设计和制造，以实现强大而高效的盐水处理，从而造福社会。将通过外联和教育活动，包括指导田纳西大学的一名研究生，诺克斯维尔和一名科罗拉多州立大学的研究生。膜蒸馏作为一种盐水处理技术的有效性受到盐水侵入膜孔（膜孔润湿）和矿物在膜表面上的沉淀（膜结垢）。该项目的目标是设计和制造一个新的仿生润湿和防垢MD膜家族，而不使用PFAS构建块。为了推进这一目标，主要研究者（PI）建议探索新的策略，通过共价连接supracolloidal结构来修改市售疏水平板膜的表面，该结构模仿弹尾的悬垂纹理及其独特的排斥低表面张力液体的能力。这些超胶体结构将通过较小胶体在较大胶体表面上的受控组装而形成，所述较大胶体具有负曲率的悬垂结构和非氟化配体。研究的具体目标是：1）阐明抗润湿膜的超胶体结构的设计标准，2）表征和解开新的仿生MD膜的抗结垢的机制，和3）使用模型盐水混合物和来自科罗拉多的石油和天然气生产领域的高盐度采出水的新MD膜的处理效果进行评估。该项目的成功完成具有潜在的变革性影响，通过产生新的基础知识和功能材料，推动无PFAS MD膜的开发，以有效和经济高效地处理高盐度盐水。为了实现本项目的教育和培训目标，主要研究者（PI）计划将本研究的结果整合到田纳西大学诺克斯维尔（UTK）和科罗拉多州立大学（CSU）的现有本科和研究生课程中。此外，PI建议利用UTK和CSU的现有项目开展外展活动，以招募和吸引来自代表性不足的群体的高中生和中学生，重点是利用生物启发材料来提高水的可持续性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many water treatment and industrial processes generate significant amounts of high-salinity brines including seawater desalination, inland brackish water desalination, and oil and gas production by fracking. The management of hazardous high-salinity brines from water desalination plants and oil/gas production wells has emerged as a global environmental challenge. Membrane distillation (MD) is a promising technology for the treatment of high-salinity brines that could reduce the amounts of brine that need to be disposed of while generating a purified water permeate to support industrial and agricultural usages. During the last decade, significant progress has been made toward the development of more efficient MD membranes with high wetting and scaling resistance for high-salinity brine treatment. However, these membranes are typically prepared by modifying their surfaces with long-chain per- and polyfluoroalkyl substances (PFAS), which have become priority pollutants due to increasing concerns about their persistence in the environment, stability, and toxicity to humans and living organisms. The overarching goal of this project is to explore the design and fabrication of wetting- and scaling-resistant MD membranes for brine treatment without the use of PFAS. Inspired by the unique repellency of springtails towards low surface tension liquids, the Principal Investigators propose to test the hypothesis that efficient MD membranes, with both high wetting resistance and high scaling resistance, can be fabricated by covalent attachment of springtail-inspired supracolloidal structures onto the surface of a hydrophobic flat sheet membrane. The successful completion of this project will benefit society through the development of new fundamental knowledge to guide the design and fabrication of PFAS-free membrane materials for robust and efficient brine treatment. Additional benefits to society will be achieved through outreach and educational activities including the mentoring of one graduate student at the University of Tennessee, Knoxville and one graduate student at Colorado State University.The effectiveness of membrane distillation (MD) as a brine treatment technology is limited by both the intrusion of brines into membrane pores (membrane pore wetting) and the precipitation of minerals on the membrane surfaces (membrane scaling). The goal of this project is to design and fabricate a new family of biomimetic wetting- and scaling-resistant MD membranes without using PFAS building blocks. To advance this goal, the Principal Investigators (PIs) proposal to explore new strategies to modify the surface of a commercially available hydrophobic flat sheet membrane by covalent attachment of supracolloidal structures that mimic the overhang texture of springtails and their unique capability to repel low surface tension liquids. These supracolloidal structures will be formed through controlled assembly of smaller colloids onto the surfaces of larger colloids that have overhang structures with negative curvature and non-fluorinated ligands. The specific objectives of the research are to: 1) Elucidate the design criteria of supracolloidal structures for wetting resistant membranes, 2) Characterize and unravel the mechanisms of scaling resistance of the new biomimetic MD membranes, and 3) Evaluate the treatment effectiveness of the new MD membranes using model brine mixtures and a high salinity produced water from an oil and gas production field in Colorado. The successful completion of this project has the potential for transformative impact through the generation of new fundamental knowledge and functional materials to advance the development of PFAS-free MD membranes for efficient and cost-effective treatment of high salinity brines. To implement the educational and training goals of this project, the Principal Investigators (PIs) plan to integrate the findings from this research into existing undergraduate and graduate courses at the University of Tennessee, Knoxville (UTK) and Colorado State University (CSU). In addition, the PIs propose to leverage existing programs at UTK and CSU to launch outreach activities to recruit and engage high and middle school students from underrepresented groups with a focus on the utilization of bioinspired materials to improve water sustainability.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.