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The crystal chemistry of Fe doped mayenite (Ca12Al14-xFexO33) samples prepared using solid state and sol-gel synthesis techniques were compared. Five samples were prepared using solid state process with varying Fe concentration (x) where x = 0, 0.05, 0.1, 0.25 and 0.3; two sets of samples were made via the sol-gel, the first set was prepared for studying the amount of Fe substituted by varying the Fe concentration where x = 0, 0.05, 0.1, 0.2, 0.3 and 0.4 and the second set was prepared for studying the firing temperature and did not contain Fe additions (x = 0). Samples produced via the sol-gel method were more likely to be single phase with incorporation of Fe2O3 while solid state samples contained multiple phases over the same range of Fe2O3 substitutions. The refined lattice parameters, of samples prepared using both methods were observed to increase with increasing Fe concentration, suggesting Fe is replacing Al since Fe has larger ionic radii than Al. Samples prepared via the sol-gel method were found to be single phase at lower temperatures compared to samples prepared via solid state synthesis. Samples synthesized using the sol-gel method were found to have multiple phases when fired at 800 ˚C but were single phase when fired at 900˚C. In comparison, samples synthesized using traditional solid state techniques showed single phase when fired at a temperature of 1350˚C.

Thesis (M.F.A.)--Rochester Institute of Technology, 1965. / Includes bibliographical references (leaves 22-23).

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Ceramic and Materials Science and Engineering." Includes bibliographical references.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on March 19, 2010). Thesis advisor: Dr. Kathleen Warner Slane. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 206-210). Available also in a digital version from Dissertation Abstracts.

Thèse (M.A.)--Université Laval, 1999. / Comprend des réf. bibliogr.

Produced water is formed in underground formations and brought up to the surface along with crude oil during production. It is by far the largest volume byproduct or waste stream. The most popular preference to deal with produced water is to re-inject it back into the formation. Produced water re-injection (PWRI) needs a treatment before injection to prevent formation blockage. Due to the increase of produced water during oil production in the west of Kuwait, an effluent treatment and water injection plants were established and commissioned in 2004 so that produced water could be used for re-injection purposes. It is estimated that oil wells in the west of Kuwait produce 15 to 40 % of produced water. The main aim of this treatment train is to reduce not only the oil-in-water amount to less than 10 ppm, but also total suspended solids to 5 ppm which is the maximum allowable concentration for re-injection and disposal. Furthermore, with respect to the upper limit for injection, the maximum number of particles between 5 and 8 microns is 200 in 0.1 ml. In practice the number is found to exceed this limit by 10 times...

This study proposed and evaluated a waste-to-resource strategy for beneficially using solid waste as ceramic raw materials. The sludge generated from waterworks and sewage treatment processes contains significant amounts of aluminum and iron, and the industrial sludge is enriched with high metal content. The hazardous metals in waste sludge may lead to metal bioaccumulation and cause adverse effects for ecosystem. This study aims to stabilize copper- and zinc-laden sludge in commonly available ceramic products, and to beneficially use waterworks and sewage sludge to incorporate waste metals. The study was first investigated by sintering simulated metal-laden sludge with Al-rich (γ-Al2O3, -Al2O3, kaolinite, mullite) and Fe-rich (Fe2O3) precursors. Secondly, the practicability of recycling Cu-bearing electroplating sludge as a part of ceramic raw materials was evaluated through thermal interaction with Al-rich precursors. Furthermore, the potential of using water and sewage treatment works sludge to stabilize metals were also examined. Sintering procedures were carried out within 650-1450 oC for 3 h, and phase transformations were studied using X-ray diffraction (XRD) with the quantification technique of Rietveld refinement analysis. The formation of CuAl2O4 spinel was initiated at 650 oC using γ-Al2O3, and the maximum copper transformation reached 80%. The copper incorporation into CuAl2O4 started at 850 oC and reached 95% in -Al2O3 system. The growth of CuAl2O4 was found at 750 oC using kaolinite, but at 900 oC in mullite system. The maximum copper transformation for both kaolinite and mullite reached ~80%. With CuAl2O4, decomposing, the formation of CuAlO2 predominated in alumina systems, but CuO and Cu2O were found in kaolinite and mullite systems. When using Fe2O3, the CuFe2O4 with tetragonal structure was observed at lower temperatures, and the cubic CuFe2O4 became predominant at 1000 oC. The formation of ZnAl2O4 spinel started at 750 oC in γ-Al2O3 system and at 950 oC in -Al2O3 system, respectively. The zinc transformation completed in both γ-Al2O3 and -Al2O3 systems at higher temperatures. The coexistence and competition between ZnAl2O4 and Zn2SiO4 were found using kaolinite and mullite. The increase of temperature to 1350 °C resulted in complete zinc transformation to ZnAl2O4 in mullite system. Through leaching tests, aluminates and ferrites were found to be superior to oxide and silicate phases in immobilizing hazardous metals. The leachates of aluminates and ferrites exhibited the behavior of incongruent dissolution, and the Zn2SiO4 leachate showed congruent dissolution. The CuAl2O4 spinel was observed when sintering Cu-laden electroplating sludge with aluminate precursors. The copper leachability decreased with CuAl2O4 developing and the lowest copper concentration in leachates was within the optimal temperature range for CuAl2O4 generation. Both copper and zinc were successfully incorporated into the spinel structure using waterworks sludge, and the cubic CuFe2O4 became the main component when using sewage sludge to stabilize copper. Overall, this study demonstrated a promising process to stabilize hazardous metals in waste materials, such as sludge, ash, and slag, through sintering with the inexpensive ceramic precursors. This may provide an avenue for economically reduce the environmental hazards of toxic metals by reliably blending them into the marketable ceramic products. / published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

Silver nanoparticles (Ag NPs) are frequently added as a disinfectant to ceramic filters used for household drinking water treatment. To provide suspension phase particle stability, Ag NPs can be synthesized using a number of different molecules to cap the metal core. The goal of this doctoral work was to advance the fundamental understanding of how stabilizing agents influence the attachment and detachment of Ag NPs from ceramic water filters. To achieve this goal, deposition experiments onto Al₂O₃ membranes and clay-based ceramic filters were performed using Ag NPs stabilized by three different agents: citrate, polyvinylpyrrolidone (PVP), and branched polyethylenimine (BPEI). Laboratory and field- scale filtration experiments were also conducted to evaluate the removal of Ag NPs from ceramics under different water conditions -- the presence of hardness and natural organic matter (NOM). Citrate-stabilized Ag NPs were found to have the highest attachment densities, regardless of filter material. Differing attachment densities for the three types of Ag NPs were extensively explained using a combination of classic Derjaguin, Landau, Verwey and Overbeek (DLVO) theory, steric forces, and particle-particle interaction energy calculations. A multilevel statistical model was built to describe the removal of Ag NPs from ceramic water filters under different water conditions. The type of Ag NP was found to affect the initial release of Ag from the filters, while the interaction of the type of Ag NP and water were found to affect the rate of removal. Hardness and NOM prolonged the release of Ag from ceramic water filters.