CAREER: 3D Printed Carbon-Metal Nanohybrid Aerogels for Highly Efficient Adsorptive/Catalytic Removal of PFASs

全氟烷基和多氟烷基物质（PFAS）是自20世纪40年代以来在众多消费品和工业应用中生产和使用的含氟有机化学品。在过去的二十年中，在地表水、地下水、土壤、污泥和生物固体中越来越多地检测到PFAS，这引起了人们对它们的持久性、稳定性和对环境的不利影响（包括对生物和人类的毒性）的极大关注。由于PFAS在污染水源中的浓度较低，以及其独特的化学特性，包括强C-F键、疏水碳尾和亲水末端头基的组合，传统的水处理技术无法有效去除和破坏PFAS。CAREER项目的总体目标是为开发一种新型综合过滤/催化反应器系统奠定基础，该系统可以从受污染的水源中提取和破坏PFAS。为了实现这一目标，首席研究员建议使用3D打印技术来探索吸附/催化石墨烯-金属纳米混合气凝胶的制造，这种气凝胶具有高表面积、可调表面化学、分层和相互连接的孔隙，用于快速水/质量传输，从而能够有效地从受污染的水源中提取和降解PFAS。该项目的成功完成将通过开发新的功能材料和基础知识来促进综合过滤和催化系统的开发，从而造福社会，该系统可以作为处理PFAS污染水的使用点（POU）过滤器。通过学生教育和培训，包括布法罗大学的一名研究生和布法罗公立学校的四名中学教师的指导，将进一步为社会带来好处。基于石墨烯的气凝胶由于其独特的结构特性，包括具有高表面积的分层/互连孔隙，可实现快速的水/质量传输，以及高效的材料再生和再利用，已成为有前途的水处理平台。将光催化和/或氧化还原活性金属纳米材料集成到石墨烯基气凝胶中，有可能为设计和构建新一代集成过滤/催化系统提供新的机会，以高效和经济地处理PFAS污染的水。作为实现这一目标的第一步，该CAREER项目的首席研究员（PI）建议利用PI实验室开发的独特3D打印方法，探索可调、自立、水稳定、多功能光/氧化还原催化石墨烯-金属纳米混合气凝胶的制造，作为PFAS处理和降解的安全有效平台。该研究的具体目标是：(1)开发一种催化石墨烯-金属纳米混合气凝胶的3D打印方法，并使用最先进的技术（包括纳米级分辨率的x射线计算机断层扫描）表征气凝胶的性质；(2)研究PFAS吸附和催化降解程度、石墨烯气凝胶尺寸和孔隙度以及水化学（包括pH、离子强度和天然有机物对材料性能的影响）之间的关系；(3)利用统计建模和傅立叶变换红外（FT-IR）光谱、x射线光电子能谱（XPS）、电子顺磁共振（EPR）光谱、液相色谱-高分辨率质谱（LC-HRMS）和离子色谱（IC）等分析工具的结合，阐明3D打印石墨烯气凝胶对PFAS的吸附和降解机制。该项目的成功完成有可能通过开发新的吸附/催化材料和产生新的基础知识来推动集成过滤/催化系统的开发，这些系统可以作为处理PFAS污染水的使用点（POU）过滤器。为了实现这个职业项目的教育和培训目标，PI将在布法罗大学开发一门新的本科/研究生课程，重点是纳米材料的合成、加工和环境修复应用。此外，PI计划与布法罗公立学校（BPS）系统的教师合作，制定课程计划，向初高中学生讲授环境污染和补救措施。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Per- and polyfluoroalkyl substances (PFAS) are fluorinated organic chemicals that have been manufactured and used in numerous consumer products and industrial applications since the 1940s. During the last two decades, increasing detection of PFAS in surface water, groundwater, soils, sludges, and biosolids has raised significant concerns about their persistence, stability, and adverse impact in the environment including toxicity to living organisms and humans. Conventional water treatment technologies cannot effectively remove and destroy PFAS due to their dilute concentration in contaminated water sources and unique chemical features, including a combination of strong C-F bonds, hydrophobic carbon tails, and hydrophilic terminal head groups. The overarching goal of this CAREER project is to lay the foundation for the development of a novel and integrated filtration/catalytic reactor system that can extract and destroy PFAS from contaminated water sources. To advance this goal, the Principal Investigator proposes to use 3D printing to explore the fabrication of adsorptive/catalytic graphene-metal nanohybrid aerogels with high surface area, tunable surface chemistry, and hierarchical and interconnected pores for fast water/mass transport to enable efficient extraction and degradation of PFAS from contaminated water sources. The successful completion of this project will benefit society through the development of new functional materials and fundamental knowledge to advance the development of an integrated filtration and catalytic system that could serve a point-of-use (POU) filter for the treatment of PFAS contaminated water. Further benefits to society will be achieved through student education and training including the mentoring of a graduate student at the University at Buffalo and four middle/school teachers from the Buffalo public schools.Graphene-based aerogels have emerged as promising water treatment platforms due to their unique structural properties including hierarchical/interconnected pores with high surface area that enable fast water/mass transport, and efficient material regeneration and reuse. The integration of photocatalytic and/or redox-active metallic nanomaterials into graphene-based aerogels have the potential to open new opportunities to design and build a new generation of integrated filtration/catalytic systems for the efficient and cost-effective treatment of PFAS contaminated water. As a first step toward this goal, the Principal Investigator (PI) of this CAREER project proposes to leverage a unique 3D printing approach developed in the PI’s laboratory to explore the fabrication of tunable, self-standing, water-stable, and multifunctional photo/redox-catalytic graphene-metal nanohybrid aerogels as safe and effective platform for PFAS treatment and degradation. The specific objectives of the research are to: (1) Develop a 3D printing approach for catalytic graphene-metal nanohybrid aerogels and characterize the aerogel properties using state-of-the-art techniques including X-ray computed tomography with nanoscale resolution; (2) Investigate the relationships between the extents of PFAS sorption and catalytic degradation, graphene aerogel size and porosity, and water chemistry including the effects of pH, ionic strength, and natural organic matter on material performance; and (3) Elucidate the mechanisms of adsorption and degradation of PFAS by the 3D printed graphene aerogels using statistical modeling and a combination of analytical tools including Fourier transformed infrared (FT-IR) spectroscopy, X-Ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy, liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS), and ion chromatography (IC). The successful completion of this project has the potential for transformative impact through the development of new adsorptive/catalytic materials and the generation of new fundamental knowledge to advance the development of integrated filtration/catalytic systems that could serve as point-of-use (POU) filters for the treatment of PFAS contaminated water. To implement the educational and training goals of this CAREER project, the PI will develop a new undergraduate/graduate course at the University at Buffalo that will focus on nanomaterial synthesis, processing, and applications to environmental remediation. In addition, the PI plans to collaborate with teachers from the Buffalo Public Schools (BPS) system to develop lesson plans to teach middle/high school students about environmental pollution and remediation.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.