Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0760. Adviser: Joseph W. Stucki. Includes bibliographical references (leaves 151-170). Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--Indiana University, Dept. of Geological Sciences, 2004. / Title from PDF t.p. (viewed Dec. 1, 2008). Source: Dissertation Abstracts International, Volume: 66-01, Section: B, page: 0166. Chair: Lisa M. Pratt.

Tetraalkylammonium cation intercalation into smectites was found to be a useful tool for the study of many aspects of smectite chemistry, including the determination of their internal surface areas and the identification of the mineral composition of Alberta oil sands bitumen. The adsorption of aromatic molecules to these organoclays has given useful insights about the nature of the interlamellar pore systems of these compounds. The grafting of organic moieties to the interlayer surface of montmorillonite was achieved by the reaction of the acidified clay with 3-chloropropyltrimethoxysilane. Nucleophilic substitution of the Cl for chelating functionalities (SH and SCH$\sb2$CH$\sb2$SH) has resulted in highly effective heavy metal adsorbents, particularly for Pb and Hg. The adsorbents could be easily regenerated by leaching out the metal with HCl. Similar materials were prepared using the layered silicates magadiite and kenyaite, but were found to be ineffective for the removal of metal ions from solution because of the congestion of the interlamellar region of these minerals by the organic functionalities which has prevented the access of the metal ions to the chelating sites. Alcohols and diols were found to condense onto the the interlamellar silanols of H-magadiite and H-kenyaite upon thermal treatment. The techniques used to characterize these compounds provided strong evidence of the formation of Si-O-C linkages between the mineral template and the organic groups. The nanocomposites thus formed were found to be stable to well beyond 400$\sp\circ$C, but did not show appreciable microporosity. The grafting interlamellar region of these silicates, whose crystal structures are still unknown. The preparation of clay-based catalysts for nitric oxide decomposition was attempted by the cointercalation of organic and metal cations into montmorillonite and by the doping of Al-pillared montmorillite by metal ions. The resulting compounds were found to promote the ortho nitrosylation of phenol in the presence of NO gas, but only in very low yield (3%). Static variable temperature studies have failed to show any catalytic decomposition of nitric oxide in the presence of these materials.

The aim of this study was to investigate, at various soil water contents, the tillage effects of two different types of injectors on soil hydraulic properties of a loamy clay soil located in Winchester, Ontario, Canada. The two injectors considered are the AerWay SSD (A) and the Kongskilde Vibro-Flex (K). The soil-properties changes associated with the injectors were assessed at ten different soil water contents for both injectors. The first part of this research involves the evaluation of field saturated hydraulic conductivity (Kfs), matrix flux potential (&phis;m), bulk density (rhob) and volumetric water content (theta) for undisturbed soil (U) and for soil disturbed by injector (D). The field saturated hydraulic conductivities measured on disturbed soil for the Kongskilde (DK) were in 80% of the cases lower than those measured on undisturbed soil (UK). In contrast, Kfs measured on disturbed soil for the AerWay (DA) were higher in 90% of the cases. These results indicate that the Kongskilde reduces the infiltration capacity of the soil, which may be the result of reduced effective porosity via the smearing of the soil surface. They also indicate that the AerWay is facilitating infiltration, most likely by fracturing the soil surface. The second part of this study involves a dye tracer experiment conducted on disturbed soil to evaluate the movement pathways of water through soil. In contrast to the AerWay, no relation could be established between liquid transport variables and the water content at which the Kongskilde was run. Greatest depths of penetration observed for the AerWay treatment occurred at run average water contents above 29.7 % vol. and below 19.7 % vol. Sorptive capacity of the upper layers was maximized when soil water contents were between 21.7 % vol. and 31.3 % vol.

Electrokinetic treatment is a promising technology to remove contaminants from clayey soils. The interaction of various processes that take place simultaneously is yet to be understood, in order to better predict the efficiency of the process in a variety of soil-contaminant situations. The electrokinetic process refers to movement of water, ions, and charged particles relative to one another under the action of an applied direct current electrical field. In this research electrokinetic experiments are conducted on saturated kaolinite specimens loaded with zinc to investigate the efficiency of contaminant removal and energy expenditure during the treatment. The effect of various electrical fields on electrokinetic remediation was studied by application of constant electrical potential and current with different intensities across the specimens. The treatment duration in various tests ranged from 3 to 73 days. Electroosmotic flow, electrical gradient variation, pH, conductivity, and zinc concentration of the anolyte, catholyte and pore solution across the specimen, were measured. The calculated electroosmotic coefficients of permeability (k$\sb{\rm e}$) were within range of literature values but were not constant over time. The migration of zinc within the soil from the anode toward the cathode was significant. Almost all transported zinc was accumulated in a thin layer of soil near the cathode chamber due to high pH environment. Formation of this low conductivity layer results in higher potential drop in this region and increase in energy expenditure. In order to reduce the amount of precipitation and increase the removal of zinc in to the cathode chamber, pH enhancement technique with application of acetic acid was employed. Neutralizing the pH in the cathode chamber (pH = 6) did not lead to increase in removal efficiency of heavy metal. However, controlling the pH at lower level (pH = 4) at the cathode compartment was successful for removal of 60% zinc from soil. Effect of the position of the reference electrode on energy consumption was also studied. Experiments under controlled electrical potential field, with positioning the reference electrode close to the cathode, indicated reasonable reduction of energy expenditure during the treatment. The principal conclusions were as follows: (1) The electrokinetic technique is effective and economical for short term remediation. (2) The constant potential electrical field demonstrated lower energy consumption compared to the constant current condition, both in short term and long term remediation. (3) Controlling the pH to a value less than 4 in the cathode compartment, successfully flushed the zinc out of the sample to the catholyte. (4) Placement of the reference electrode close to the cathode (working) electrode, decreased the amount of energy expenditure significantly.

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