

@mastersthesis {6651,
	title = {Removal of inorganic and trace organic contaminants by electrodialysis},
	year = {2010},
	note = {U571614},
	school = {The University of Edinburgh (United Kingdom)},
	type = {phdPh.{D}.},
	address = {Ann Arbor},
	abstract = {\&lt;P class=MsoNormal style=\&quot;MARGIN: 0in 0in 10pt\&quot;\&gt;\&lt;FONT face=Calibri\&gt;The purpose of this study was to elucidate the mechanisms of inorganic and trace organic contaminant removal by electrodialysis (ED). The inorganic contaminants fluoride, nitrate and boron were selected due to their ubiquitous nature in the environment and public health concerns resulting from longterm exposure. The hydrated radius and strength of hydration shells played a significant role in ionic transport, whereby nitrate with a smaller hydrated radius was removed more effectively (94.1 \%) than fluoride (68.3 \%) with a larger hydrated radius. While fluoride and nitrate removal was pH independent, the pH dependent speciation of boron enhanced its removal with increasing pH. Territorial binding and/or complexation of the inorganics with organic matter enhanced removal. The removal of a range of trace inorganics (e.g. arsenic, calcium, magnesium, uranium) from a brackish groundwater from a remote Australian community was investigated. Undissociated inorganics were not transported through the membranes, whereas dissociated inorganics were due to electrostatic attraction. At acidic-neutral conditions ionic transport was the dominant removal mechanism. At neutral to alkaline conditions insoluble carbonate species precipitated and deposited as a membrane scaling layer (60 {\textquestiondown}m). This has serious implications for the long-term practical applicability of ED to treat real waters as scaling increased ED stack resistance (pH 3: 27.5 4, pH 11: 50 4) and decreased total dissolved solids removal (pH 3: 99 \%, pH 11: 89.5 \%). While the treatment of trace organics by other membrane processes has been widely studied, their fate in ED and interaction with ED membranes is relatively unknown. Trace contaminant-membrane interaction studies were undertaken to quantify the partitioning of trace organics; namely steroidal hormones and the pesticide endosulfan, to ED membranes by measuring membrane-water partition coefficients (log KM). The extremely high sorption capacity of the membranes was attributed to hydrogen bonding between the trace organic and membrane functional groups. Hormone sorption during ED was influenced by solution pH and organic matter. In the case of estrone, membrane sorption decreased at pH 11 (487 {\textquestiondown}g/cm3) compared to pH 7 (591 {\textquestiondown}g/cm3) due to dissociation and membrane electrostatic repulsion .At pH 11, repulsion between dissociated estrone and HA coupled with membrane electrostatic attraction resulted in increased sorption. The findings from this study highlight that the transport of trace contaminants will depend largely on the characteristics of the membranes used in the ED process as well as the physicochemical characteristics of the contaminants, their interaction with the ED membranes and the presence of other inorganic and/or organic compounds. \&lt;/FONT\&gt;\&lt;/P\&gt;},
	keywords = {(UMI)AAIU571614, 0554:Civil engineering, Applied sciences, Bibliographies, Civil engineering, http://hdl.handle.net/1842/3998, Psychology{\textendash}Abstracting, Statistics},
	url = {http://search.proquest.com/docview/1033191129?accountid=14270},
	author = {Banasiak, Laura Joan}
}
