Tailoring thin-film nanocomposite membranes for water reuse applications

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CBET 1336532 Orlando Coronell (PI), Howard Weinberg (co-PI)The University of North Carolina at Chapel HillWith increasing stress placed on the quality of drinking water by contamination and demand, alternatives to traditional water sources and treatment need to be evaluated. A promising option for supplementing the drinking water supply is the use of high quality recycled waters produced from the advanced treatment of impaired surface waters or secondary wastewater effluent. Advanced water treatment plants often use high-pressure membranes because they can remove most contaminants in one step through a combination of size exclusion, electrostatic repulsion, and low permeability to contaminants. Zeolite thin film nanocomposites (TFNs) are a new type of high-pressure membrane that can reduce the energy costs of membrane treatment by increasing water permeability without compromising contaminant rejection and in some cases even improving upon it. While the energy saving benefits of TFNs are much greater for the treatment of low salinity waters, there is no evidence in the literature that TFNs have been optimized for these applications nor has their rejection of organic contaminants been evaluated. Accordingly, the objectives of this project are to: (1) optimize zeolite TFNs for water reuse applications, specifically by increasing water permeability and rejection of contaminants of emerging concern (CECs), (2) understand how membrane performance is correlated to the physico-chemical properties of membranes, and (3) elucidate the relationship between the physico-chemical properties of contaminants and their rejection efficiency by TFNs. The contaminants that this project will evaluate were selected because of their potential harm to human and ecological health, are of high occurrence in the waters of interest, and are indicators of overall water quality. The contaminants selected include regulated and unregulated disinfection byproducts, chemicals on the latest contaminant candidate list of the U.S. Environmental Protection Agency, and other CECs. This interdisciplinary project will decrease the cost of water reuse through the development and evaluation of more efficient and effective membranes for treatment of low quality water and certain wastewaters. This technology will be beneficial not just in water treatment applications but also in fields using membrane separations such as artificial organs, fuel cells, gas separations, and other industrial separations. The research and educational activities of this project will also have the following additional broader and societal impacts: (1) enhancement of secondary education through the development and dissemination of scientific educational materials, (2) encouragement of science and engineering career paths through dissemination of interactive educational materials, and (3) interdisciplinary and collaborative research experience provided to graduate and undergraduate students, including underrepresented groups in chemistry and engineering (women and minorities) through intensive training in the development and application of membranes to protect public health.