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

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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.