Collaborative Research: Transformation, interaction and toxicity of emerging 2D nanomaterials free-standing and embedded onto nanocomposite membranes for PFAS degradation

全氟烷基和多氟烷基物质(PFAS)是一类含有强碳氟键的化合物，自20世纪40年代以来一直用于公共和工业用途。在各种环境基质和活体(包括人类)中检测到这些化学物质，以及它们的高度稳定性和致毒潜力，已经引起了重大的公共卫生问题。由于这些化学物质高度稳定的碳氟键以及不同的疏水性和极性，传统的水和废水处理工艺在去除和降解这些化学物质方面效率低下。这项拟议项目的目标是设计一种新型的反应性纳米复合膜过滤器，可以同时将这些化合物从水中分离出来，并将它们降解为毒性较低或无害的副产品。为了实现这一目标，主要研究人员将结合纳米材料、膜分离和生态毒性方面的专业知识，使用新型平面二维纳米材料来制备具有高水流量、稳定性和抗污染性能的催化纳滤膜。这将使作为优先污染物的这些化学品以及这类化合物中的其他新兴化学品得以去除和降解。同时，将测试2D纳米材料和由此产生的副产品对模型生物的毒性，以确定这一新处理过程的可持续性和有效性。该项目的成功完成将通过发展有关新的2D纳米材料及其与这些含氟化合物的相互作用的基本知识来造福社会，从而开发一个集成膜反应器系统，该系统既可以作为集中式水处理系统，也可以作为处理被这些化合物污染的水的使用点过滤器。该项目将通过对人数不足的本科生和研究生进行教育和培训，进一步造福社会。该项目由CBET纳米尺度相互作用计划和已建立的促进竞争研究计划(EPSCoR)共同资助。该项目的目标是为有效降解新出现的优先关注的持久性污染物--全氟烷基和多氟烷基物质--的2D无机光催化膜的可持续设计奠定基础。将使用具有不同电子和物理化学性质的新型2D纳米材料，非金属磷烯和类金属六方氮化硼，这些材料已显示出这些化合物的降解证据。本研究项目旨在解决关于这些性质如何影响水介质中独立形式的二维六方氮化硼和磷烯纳米片以及将它们结合到纳米复合膜上后的转化、稳定性和毒性的知识空白。研究小组将研究2D纳米材料的降解潜力及其与这些化合物的相互作用机制，识别分解产物，并使用模式生物秀丽线虫评估其降解产物的毒性，以验证分解产物的毒性低于最初的化学品。为了实现这一点，将使用最先进的纳米表征技术、分子和热力学建模、分析化学和分子生物学技术。这些发现将提供有关非碳2D纳米材料的潜在转变和2D纳米材料的整体稳定性的知识，这将有助于理解其他具有不同电子和物理化学性质的非碳2D材料。此外，虽然将非碳2D纳米材料混合到聚合物膜上以去除和销毁新出现的水污染物的化学是这里的重点，但同样的化学可以用于制造能够潜在地捕获和摧毁空气传播的毒素，如病毒的空气滤膜。该项目还将通过整合研究和教育、指导本科生和研究生、与社区组织接触以及在科学、技术和经济管理领域吸引代表性不足的学生，来加强主要调查人员正在进行的教育和外联活动。向最终用户传播技术将通过同行评议的手稿和会议发言来完成。该项目由CBET纳米尺度互动计划和既定的激励竞争研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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 a class of chemical compounds containing strong carbon-fluorine bonds and have been produced for public and industrial usage since the 1940s. The detection of these chemicals in various environmental matrices and living organisms (including humans) along with their high stability and toxicogenic potential have raised significant public health concerns. Conventional water and wastewater treatment processes are ineffective at removing and degrading these chemicals due to their highly stable carbon-fluorine bonds along with varying hydrophobicity and polarity. The goal of this proposed project is to design a new class of reactive nanocomposite membrane filters that will simultaneously separate these compounds from water and degrade them to less- or non-toxic byproducts. To achieve this goal, the principal investigators will combine expertise from nanomaterials, membrane separations, and ecotoxicity using novel planar two-dimensional nanomaterials to fabricate catalytic nanofiltration membranes with high water flow rate, stability, and antifouling properties. This will enable removal and degradation of these chemicals which are priority pollutants as well as other emerging chemicals in this family of compounds. At the same time, the 2D nanomaterials and resulting byproducts will be tested for their toxicity to model organisms to determine the sustainability and effectiveness of this new treatment process. The successful completion of this project will benefit society through the development of fundamental knowledge about the new 2D nanomaterials and their interactions with these fluorinated compounds for the development of an integrated membrane reactor system that could serve both as a centralized water treatment system and a point-of-use filter for the treatment of water contaminated with these compounds. This project will further benefit society through education and training of underrepresented undergraduate and graduate students. This project is jointly funded by the CBET Nanoscale Interactions Program and the Established Program to Stimulate Competitive Research (EPSCoR).The goal of this project is to develop a fundamental understanding for the sustainable design of 2D inorganic photocatalytic membranes for effective degradation of the priority persistent pollutants of emerging concern, Per- and polyfluoroalkyl substances. Novel 2D nanomaterials with differing electronic and physicochemical properties, non-metallic phosphorene and metalloid hexagonal boron nitride that have shown evidence for degradation of these compounds, will be employed. This research project aims to address the knowledge gap on how these properties affect transformation, stability, and toxicity of the 2D hexagonal boron nitride and phosphorene nanosheets in free-standing form in aqueous media and after incorporating them onto nanocomposite membranes. The research team will examine the degradation potential of the 2D nanomaterials and their mechanisms of interactions with these compounds, identify breakdown products, and evaluate toxicity of their degradation products using a model organism, Caenorhabditis elegans, to verify that the breakdown products are less toxic than the initial chemicals. To achieve this, state-of-the-art nanoscale characterization techniques, molecular and thermodynamic modeling, analytical chemistry, and molecular biology techniques will be employed. Findings will provide knowledge about the potential transformation of non-carbon 2D nanomaterials and the overall stability of 2D nanomaterials which will be useful to understanding other non-carbon 2D materials with varied electronic and physicochemical properties. Furthermore, while the chemistry of blending non-carbon 2D nanomaterials onto polymeric membranes for the removal and destruction of emerging water pollutants is the focus here, the same chemistry can be used to fabricate air filtration membranes that would be able to potentially capture and destroy airborne toxins, such as viruses. This project will also strengthen the ongoing educational and outreach activities of the principal investigators by integrating research and education, mentoring undergraduate and graduate students, reaching out to community organizations, and engaging underrepresented students in STEM fields. Technology dissemination to end users will be accomplished through peer-reviewed manuscripts and conference presentations. This project is jointly funded by the CBET Nanoscale Interactions Program and the Established Program to Stimulate Competitive Research (EPSCoR).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.