Tuning Activated Carbon Nanofiber Nonwoven Membranes for Selective Sorption of Micropollutants.

1438518VADAS用于选择性吸附微污染物的活性碳纳米纤维非织造薄膜调谐面对日益增长的水需求，面对可获得的高质量水源，已导致替代来源的发展，例如含有低水平污染物或微污染物的再生废水。许多微污染物不能通过常规的水和废水处理系统去除。针对微污染物特性的现有三级处理具有高能量需求、较差的可伸缩性和/或副产品形成。生产活性碳纳米纤维非织造材料的材料加工技术的进步，加上化学合成技术的创新，为开发基于吸附过程的创新水处理技术提供了机会，这些过程：(I)不受传质动力学的限制；(Ii)针对极性和/或离子微污染物的物理化学性质；以及(Iii)具有高单位质量的吸附能力，并且对目标污染物具有选择性。活性碳纳米纤维非织造布材料具有高比表面积，克服了传质限制，同时其大孔隙率使高水通量成为可能。此外，该材料还可以表面功能化，以增强对中性、阳离子或阴离子有机或无机微污染物的吸附。这项研究的最终目标是确定用于水处理的具有可调表面化学的新型高比表面积吸附剂的途径。PIS将为参加康涅狄格大学达芬奇方案的初中和高中教师开发一个关于水处理的教学模块。教师将继续在课堂上向学生传播这些概念。PIS将继续吸引学生研究人员，因为他们指导研究生和本科生研究人员。学生们将有一个独特的机会与具有环境工程、化学工程和合成化学专业知识的PI指导团队合作。这项工作将产生一种具有高比表面积、高通量和可调表面化学的吸附剂。对制造和活化过程的系统研究将指导基于孔分布的特定吸着剂应用的材料设计。这里探索的表面改性方法使新的方案能够使具有特定物理化学性质的纳米纤维碳功能化，同时保持材料的结构完整性。此外，由于定义了孔结构和连接的相邻官能团，污染物的专一性得到了增强。这为开发低调的使用点处理设备打开了大门，该设备具有针对多种污染物的模块化组装。为实现这一目标，将开展三项主要研究活动。任务1：优化ACNFN实验材料制备条件以提高力学性能。通过电子显微镜、透气仪、氮气吸附、拉伸强度和弹性模数等测试手段，研究了ACNFN材料的制备工艺参数，包括用于增强纤维粘结的溶剂蒸汽暴露和压延，以及热解温度和活化工艺对材料孔隙率和强度的影响。任务2：通过使用新的衍生化方法(如渗透或臭氧化)，使ACNFN的表面具有针对不同物理化学性质的微污染物的基团(例如，阴离子有机化合物的季铵盐或阳离子无机化合物的螯合基团)。任务3：表征我们新生成的ACNFN吸附剂在合成水和真实水中的平衡容量和吸附动力学。重点是两种具有代表性的微污染物，布洛芬和CD，基于对污染物的关注，在工作pH(6-8)下的电离状态，易于定量，以及与潜在吸附位置的主要相互作用机制。

1438518VadasTuning Activated Carbon Nanofiber Nonwoven Membranes for Selective Sorption of MicropollutantsThe increasing demand for water, in the face of declining high quality source availability, has led to the development of alternative sources, such as reclaimed wastewater, that contain low-levels of contaminants, or micropollutants. Many micropollutants are not amenable to removal by conventional water and wastewater treatment systems. Available tertiary treatments that target micropollutant properties have high energy requirements, poor scalability, and/or byproduct formation. Advances in material processing to produce activated carbon nanofiber nonwoven materials, coupled with innovations in chemical synthesis techniques, provide opportunities to develop innovative water treatment technologies that are based on sorptive processes that: (i) are not limited by mass transfer kinetics; (ii) are targeted to the physico-chemical properties of polar and/or ionic micropollutants, and (iii) have high sorptive capacity per unit mass and are selective towards target contaminants. The activated carbon nanofiber nonwoven material has a high specific surface area externally available which overcomes mass transfer limitations, while its macroporosity enables high fluxes of water. In addition, the material can be surface-functionalized to enhance sorption of neutral, cationic, or anionic organic or inorganic micropollutants. The ultimate goal of this research is to identify pathways to the creation of a novel high surface area sorbent with tunable surface chemistry for use in water treatment. The PIs will develop a teaching module on water treatment for middle- and high-school teachers participating in the University of Connecticut daVinci Program. Teachers will continue to disseminate these concepts with students in their classes. PIs will continue engaging student researchers as they mentor graduate and undergraduate researchers. Students will have a unique opportunity to work with a guiding PI team with expertise in environmental engineering, chemical engineering, and synthetic chemistry.This work will generate a sorbent with high surface area, high flux and tunable surface chemistry. Systematic studies of fabrication and activation procedures will guide design of materials for specific sorbent applications based on pore distributions. The approach to surface modification explored here enables new protocols to functionalize nanofibrous carbons with specific physico-chemical properties, while maintaining the structural integrity of the material. In addition, contaminant specificity is enhanced due to the defined pore structure and adjacent functional groups attached. This opens the door to developing low-profile point-of-use treatment devices with modular assembly to target multiple contaminants. Three major research activities will be pursued to achieve the objective. Task 1: Optimize the conditions of experimental ACNFN material fabrication to enhance mechanical properties. Fabrication parameters, including solvent vapor exposure and calendaring to reinforce fiber bonding, and pyrolysis temperature and activation technique on ACNFN material porosity and strength will be examined using electron microscopy, porosimetry, nitrogen adsorption, tensile strength and elastic modulus. Task 2: Functionalize the surface of ACNFN with groups targeted to micropollutants of differing physico-chemical properties (e.g. quaternary ammonium for anionic organic compounds or chelating groups for cationic inorganic compounds) through the use of novel derivatization methodologies (e.g. osmylation or ozonation). Task 3: Characterize both the equilibrium capacity and sorption kinetics of our newly generated ACNFN sorbent in synthetic and real waters. The focus is on two representative micropollutants, ibuprofen and Cd, selected based on contaminant concern, the ionization state at the working pH (6-8), the ease of quantification, and the primary interaction mechanism with potential sorption sites.