ERASE-PFAS: Bottom-up synthesis of polymeric membranes for PFAS sequestration

防腐和防污渍涂层越来越多地出现在我们的日常生活中，有助于清洁物体和/或材料，减缓材料的变质，并保护它们免受化学或热应力的影响。当然，随着这些涂料性能的提高，它们对公众日益增长的需求变得更具吸引力，从而推动了它们的生产。构成这些涂料一部分的一大类分子是全氟烷基物质和多氟烷基物质(PFAS)。已经确定了数千种全氟化肥，其中一些是大规模生产的。全氟辛烷磺酸固有的化学性质使它们在泄漏到生态系统中时基本上牢不可破。不幸的是，美国各地饮用水中全氟辛烷磺酸的存在已经有了很好的记录，人类摄入全氟辛烷磺酸已与许多疾病和癌症有关。摆在我们面前的重大挑战是找到从环境中去除全氟辛烷磺酸的方法，特别是在这些物质污染饮用水水源的情况下。该项目的目标是开发能够过滤水的合成膜，将大部分全氟辛烷磺酸去除到远低于美国环境保护局设定的百万分之70的门槛以下。拟议研究的成功完成将开发化学途径和基本认识，以创造高性能的膜来去除水中的全氟辛烷磺酸，最终达到保护公众健康的目标。还将通过教育和培训为社会带来其他好处，包括对莱斯大学的两名研究生进行指导。聚氟烷基物质(PFAS)是通常由1)阴离子头基、羧酸盐或磺酸盐组成的分子，以及2)氟化主链，它们对环境退化具有令人难以置信的抵抗力。它们的化学和热稳定性使其成为保护材料免受降解或火灾等事件影响的理想物质。在与健康相关的影响在世纪之交左右开始禁止某些物种之前，人们生产了大量的FPA。然而，其产生的大量污染物，加上其对环境的持久性，导致了对环境的广泛污染，特别是饮用水水源。已记录的全氟辛烷磺酸对人类的健康风险包括孕妇的严重畸形、成人的癌症、肝脏功能障碍、甲状腺疾病、生育力下降、高胆固醇和肥胖。鉴于全氟辛烷磺酸对大多数化学吸附剂的亲和力和结合力较弱，未来的挑战是设计能够将其从受污染的水中去除的膜。该项目的总体目标是为阴离子全氟辛烷磺酸设计识别部位，稍后将开发这种识别位点，并将其并入用于过滤水的膜中，以隔离长链和短链全氟辛烷磺酸。为了实现这一中心目标，该项目将1)设计嵌入在超分子支架中的识别位点；2)合成、表征和确定最有希望的支架的阴离子结合性能；以及3)通过在超分子支架中加入烯烃和/或环氧化物官能团来聚合最有希望的结构，并测试它们在水样中的PFAS固定性能。该项目的成功完成将建立加强分子支架内全氟辛烷磺酸结合的基本参数，以便以后将这些知识转化为聚合物过滤材料的设计。教育和外展活动包括为高中生和本科生创建研讨会和动手工作坊。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。

Anti-corrosion and anti-stain coatings have been increasingly present in our daily lives facilitating the cleaning of objects and/or materials, slowing down material’s deterioration, and protecting them against chemical or thermal stress. Naturally, as these coatings increase in performance, they become more attractive to the public increasing demand, and thus driving forward their manufacture. One large class of molecules forming part of these coatings are the per- and polyfluoroalkyl substances (PFAS). Several thousands of PFAS have been identified, some of which are made in a very large scale. The inherent chemical properties of PFAS makes them essentially unbreakable when they leak into ecosystems. Unfortunately, the presence of PFAS in drinking water across the U.S. is now well-documented and human ingestion of PFAS has been associated with a number of diseases and cancer. The grand challenge ahead of us is to find ways of removing PFAS from the environment, especially when these substances contaminate drinking water sources. The goal of this project is to develop synthetic membranes capable of filtering water to remove the majority of the PFAS to well below the threshold of 70 parts-per-trillion, as established by the U.S. Environmental Protection Agency. Successful completion of the proposed research will develop the chemical pathways and basic understanding to create high-performing membranes to remove PFAS from water, ultimately with the goal of protecting public health. Additional benefits to society will be accomplished through education and training including the mentoring of two graduate students at Rice University.Per- and polyfluoroalkyl substances (PFAS) are molecules generally composed of 1) an anionic head group, carboxylate or sulfonate; and 2) a fluorinated backbone, which are incredibly resistant to environmental degradation. Their chemical and thermal stability made them ideal substances to use to protect materials from degrading or from events such as fires. Enormous quantities of FPAS were produced until health-related effects initiated the ban of certain species around the turn of the century. However, the large quantity that was produced coupled with their environmental persistence has resulted in widespread contamination of the environment, especially drinking water sources. Documented health risks posed by PFAS to humans include severe malformations in pregnant women, cancer in adults, liver malfunction, thyroid disease, decreased fertility, high cholesterol, and obesity. Given that PFAS have weak affinity and binding towards most chemical adsorbents, the challenge ahead is to design membranes capable of removing them from contaminated water. The overarching goal of this project is to design recognition sites for anionic PFAS, which will be later developed and incorporated into membranes used to filter water that would sequester long- and short-chain PFAS. To accomplish this central objective, the project will 1) design recognition sites embedded within supramolecular scaffolds; 2) synthesize, characterize, and determine the anion binding properties of the most promising scaffolds; and 3) polymerize the most promising architectures via olefinic and/or epoxide functional groups incorporated into the supramolecular scaffold, and test their PFAS sequestration properties in aqueous samples. The successful completion of this project will establish the fundamental parameters to enhance PFAS binding within molecular scaffolds to later translate this knowledge into the design of polymeric filtration materials. Education and outreach activities include creating seminars and hands-on workshops for high school and undergraduate students.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.