%0 PDF %T Emulsion-Based Delivery of Alkalinity for Subsurface pH Control %A Muller, Katherine. %8 2017-04-19 %R http://localhost/files/vh53x706k %X Abstract: Emulsions are widely utilized to encapsulate, deliver, and release active ingredients and are routinely used in environmental applications. Alkalinity-releasing particles can be encapsulated within emulsions to provide long term pH control as alkalinity slowly releases from the oil droplets retained in the subsurface. Through a combination of laboratory experiments and mathematical modeling, this work addresses: (i) emulsion transport and retention in porous media; (ii) alkalinity release from particles encapsulated in emulsion oil droplets; and (iii) the ability of emulsions to provide passive, yet sustained, pH treatment. Concentrated emulsion transport and deposition behavior was predicted from particle transport models adapted and parameterized using data from transport of dilute emulsion. Dispersivity was found to increase with decreasing water saturation (i.e., from mass retention) in emulsion systems, but also more broadly in partially saturated air-water and NAPL-water systems as a whole. Encapsulation of alkalinity-releasing particles within the emulsion oil droplets was able to control the rate of alkalinity release through the increased resistance to mass transfer via the oil-water interface (orders of magnitude reduction in rates of release). Results illustrate how emulsions containing only limited loadings of MgO and CaCO3 particle are able to provide long-term pH treatment in columns containing sandy porous media. Models developed and employed herein provide a tool that may aid in designing treatments employing oil-in-water emulsions, as well as providing insight into how to best reach or maintain site specific pH requirements.; Thesis (Ph.D.)--Tufts University, 2016.; Submitted to the Dept. of Civil Engineering.; Advisor: C. Andrew Ramsburg.; Committee: Steven Chapra, Robert Viseca, Hyunmin Yi, and Brent Sleep.; Keyword: Environmental engineering. %[ 2022-10-11 %9 Text %~ Tufts Digital Library %W Institution