SGER: Zone Refining of Aqueous Solutions

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Abstract Proposal Title: SGER Zone Refining of Aqueous Solutions Proposal Number: CTS-0553056 Principal Investigator: Philip J. Parker, Institution: University of Wisconsin - PlattevilleZone refining is a freeze concentration technique that has been used extensively to obtain extremely high purity crystals in a variety of industrial settings. The process involves moving a heating zone along a crystalline material. The temperature of the heating zone is higher than the crystalline material's melting temperature; thus the heating zone induces a freezing front to move along the solid crystal. Like nearly all freezing fronts, this freezing front pushes impurities ahead of itself. The moving freezing front segregates the impurities at one end of the sample; repeated passes by the heating zone results in a high purity solid. There are no reports in the literature on applying zone refining to frozen aqueous solutions. Given the ubiquity of aqueous solutions, the process could have far reaching consequences in fields as disparate as drinking water treatment, food processing, or industrial wastewater purification. Indeed, virtually any field of study that needs to either remove contaminants from an aqueous solution, or to concentrate contaminants in an aqueous solution, may be impacted by the results of this exploratory study. The proposed work will explore the impact of three variables on the zone refining process for aqueous solutions: zone travel speed; type of contaminant; and the number of zone passes. Four types of contaminants will be used, representative of an inorganic salt; an organic compound; suspended solids; and a heavy metal. The intellectual merit of the proposed work is evident in many ways. First, the work will increase the understanding of the freeze concentration process and how freeze concentration can be harnessed using zone refining. Second, the PI has extensive experience in research associated with freezing, including fundamental studies of ice crystallography and applied studies on the impact of freeze/thaw conditioning on water and wastewater treatment residuals. Third, the proposed work will be readily supported by the facilities at the PI's institution (the University of Wisconsin-Platteville, or UWP). Finally, the proposed work is highly innovative in that no published information demonstrates the effectiveness of zone refining on aqueous solutions.From a broader impacts perspective, this study will have a positive influence on undergraduate engineering students. The undergraduate research assistants will benefit from the inquiry and discovery that takes place in engineering research, and the exposure to research will introduce them to the possibility of attending graduate school, something often missing at a Primarily Undergraduate Institution such as UWP. Also, all students enrolled in Introduction to Environmental Engineering will have an opportunity to use the apparatus in a laboratory setting. Finally, if the results are promising, the work will most likely lead to productive and innovative partnerships between fields such as water treatment and crystal growth.