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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Identification of active agents for tetrachloroethylene degradation in Portland cement slurry containing ferrous iron

Ko, Sae Bom 16 August 2006 (has links)
Fe(II)-based degradative solidification/stabilization (Fe(II)-DS/S) technology is the modification of conventional solidification/stabilization (S/S). Inorganic pollutants are immobilized by Fe(II)-DS/S while organic pollutants are destroyed. Experimental studies were conducted to identify the active agents for Tetrachloroethylene (PCE) degradation as well as the conditions that enhance the formation of the active agents in the Fe(II)-DS/S system. PCE was chosen as a model chlorinated aliphatic hydrocarbon in this study. First, the conditions that lead to maximizing production of the active agents were identified by measuring the ability of various chemical mixtures to degrade PCE. Results showed that Fe(II), Fe(III), Ca, and Cl were the the important elements that affect degradation activity. Elemental compositions of the mixtures and the conditions affecting solid formation might be the important factors in determining how active solids are formed. Second, instrumental analyses (XRD, SEM, SEM-EDS) were used to identify minerals in chemical mixtures that have high activities. Results indicate that active agents for PCE degradation in Portland cement slurries and in cement extracts might be one of several AFm phases. However, systems without cement did not form the same solids as those with cement or cement extract. Ferrous hydroxide was identified as a major solid phase formed in systems without cement. Finally, the effect of using different types of ordinary Portland cement (OPC) on PCE degradation rate during Fe(II)-DS/S was examined and the solids were examined by instrumental analyses (XRD, SEM, SEM-EDS). Four different OPC (Txi, Lehigh, Quikrete, and Capitol) showed different PCE degradation behaviors. Pseudo first-order kinetics was observed for Capitol and Txi OPC and second-order kinetics was observed for Quikrete. In the case of Lehigh cement, pseudo first-order kinetics was observed in cement slurry and second-order kinetics in cement extract. Calcium aluminum hydroxide hydrates dominated solids made with Txi, Quikrete, and Lehigh cements and Friedel’s salt was the major phase found in solids made with Capitol cements. Fe tended to be associated with hexagonal thin plate particles, which were supposed to be a LDH.
2

Incorpora??o de res?duo de perfura??o em matriz cer?mica: estabiliza??o por solidifica??o / Residue incorporation drilling ceramic matrix: stabilization by solidilication

C?mara, Ana Paula Costa 29 July 2013 (has links)
Made available in DSpace on 2014-12-17T15:01:56Z (GMT). No. of bitstreams: 1 AnaPCC_TESE_Parcial.pdf: 421102 bytes, checksum: 073b73c95b7ac8b4269179af4e3a1726 (MD5) Previous issue date: 2013-07-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / One of the waste generated during the drilling of oil wells are gravel which are impregnated of drilling fluid. This residue consists of highly toxic chemicals, including toxic metals. This study suggests an alternative process to the treatment of this waste, by incorporating it the form of raw material in the ceramic matrix , and by solidification and stabilize the metals present, Aluminum (Al), Iron (Fe), Manganese (Mn) and Zinc (Zn). The raw materials were characterized by the techniques of X ray fluorescence (FRX), X ray diffraction (DRX), laser granulometry (GL), thermogravimetry (TG) and differential thermal analysis (ADT). To evaluate the percentage of gravel effect the environmental and technological properties were obtained from formulations containing 0, 10 and 20 % by weight of gravel in the ceramic matrix. After sintering at temperatures 1080, 1120 and 1160 ?C, the samples were tested for water absorption, the linear shrinkage firing, voltage of rupture and solubility. The results obtained showed that the stabilization by solidification, is a viable alternative to safe disposal of waste drilling. Ceramics products can be used in the manufacture of solid bricks / Um dos res?duos gerados durante a perfura??o de po?os de petr?leo s?o os cascalhos que ficam impregnados por fluido de perfura??o. Este res?duo ? composto por produtos qu?micos de alta toxidade, entre eles os metais t?xicos. Este estudo prop?e um processo alternativo ao tratamento deste res?duo, incorporando-o na forma de mat?ria-prima em matriz cer?mica, e atrav?s da solidifica??o estabilizar os metais t?xicos presentes, Alum?nio (Al), Ferro (Fe), Mangan?s (Mn) e Zinco (Zn). As mat?rias-primas foram caracterizadas por fluoresc?ncia de raios X (FRX), difratometria de raios X (DRX), granulometria a laser (GL), termogravimetria (TG) e an?lise t?rmica diferencial (ADT). Para avaliar o efeito do percentual de cascalho nas propriedades tecnol?gicas e ambiental, foram obtidas formula??es contendo 0, 10 e 20 % em massa do cascalho na matriz cer?mica. Ap?s sinteriza??o ?s temperaturas de 1080, 1120 e 1160 ?C, as amostras foram submetidas a ensaios de absor??o de ?gua, retra??o linear de queima, tens?o de ruptura ? flex?o e solubilidade. Os resultados alcan?ados mostraram que a t?cnica de estabiliza??o por solidifica??o, ? uma alternativa vi?vel a destina??o segura do res?duo de perfura??o. Os produtos cer?micos obtidos podem ser utilizados na fabrica??o de tijolos maci?os e blocos cer?micos de alvenaria, em determinados percentuais e temperaturas de queima descritas neste trabalho / 2020-01-01

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