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postgraduate thesis: Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation

TitleCharacterization of metal stabilization effect by X-ray diffraction technique and nano-indentation
Authors
Advisors
Advisor(s):Shih, K
Issue Date2011
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
He, Y. [贺悅]. (2011). Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4775306
AbstractThe technological development and application of waste-to-resource strategy is significantly critical and crucial in both environmental and manufacturing industries, via which we do not only provide practical treatments to toxic waste materials but also translate them into usable products. It has been considered as a preferred method which should be applied in future wastewater treatment strategies. In this study, we investigated the process of incorporating cadmium oxide and nickel oxide into ceramic-based materials with the phases of CdAl4O7, and CdFe2O4. Such products are of less harmful effect to the natural environment and can also be of beneficial use with their good mechanical properties identified by nano-indentation. We proved the possibility and provided an opportunity to convert the waste from wastewater treatment process to a new material resource. XRD is preferred for characterizing solid mixtures to determine the relative abundances of crystalline phases during the reaction process. As a result, we can obtain the relative abundance information on the growth of the crystalline products, such as CdAl4O7, and CdFe2O4 according to the change of fabrication temperatures. In that case, the starting reaction temperature and the optimized temperature (at which the completed reaction could be achieved) could be revealed. In Cd-Al system, the starting temperature for CdAl4O7 formation is 900 °C, and the optimized formation temperature is around 1020 °C. On the other hand, for Cd-Fe system, such temperatures are of 700 °C and 850 °C correspondingly. In our research, it is shown that the ceramic-process is an effective strategy to stabilize the waste hazardous metals (cadmium and nickel) by materials such as aluminate, ferrite, and kaolin commonly used in ceramic industry. Through this method, the difficult-to-treat wasted metals would become reusable and applied in building and infrastructure projects. Products containing CdAl4O7, CdFe2O4 and NiAl2O4 have shown higher resistance to acidic leaching, comparing to CdO and NiO used as the starting materials to simulate the waste metal forms discharged from the industrial stream. Furthermore, similar measurements by alkaline attack on the sintered products (NiAl2O4 containing samples) were also studied. Besides the investigation to leaching behavior, the mechanical properties are also measured by nano-indentation in our work. The incorporation of metal waste into the fabrication of ceramic products is valuable due to the preferred stabilization mechanisms of crystal structures and the large volume of ceramic products needed by the construction industry. Furthermore, because the product safety and functionality should not be compromised, a fundamental understanding of the surface properties of metal containing phases should be further established, rather than relying solely on data from regulatory tests on bulk samples. Therefore, the results of this study demonstrate the superior mechanical properties of nickel spinel containing products, comparing to the cristobalite silica matrix, under severe acid attack.
DegreeMaster of Philosophy
SubjectX-ray crystallography.
Nanotechnology.
Nickel - Environmental aspects.
Cadmium - Environmental aspects.
Ceramic materials - Environmental aspects.
Dept/ProgramCivil Engineering

 

DC FieldValueLanguage
dc.contributor.advisorShih, K-
dc.contributor.authorHe, Yue-
dc.contributor.author贺悦-
dc.date.issued2011-
dc.identifier.citationHe, Y. [贺悅]. (2011). Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4775306-
dc.description.abstractThe technological development and application of waste-to-resource strategy is significantly critical and crucial in both environmental and manufacturing industries, via which we do not only provide practical treatments to toxic waste materials but also translate them into usable products. It has been considered as a preferred method which should be applied in future wastewater treatment strategies. In this study, we investigated the process of incorporating cadmium oxide and nickel oxide into ceramic-based materials with the phases of CdAl4O7, and CdFe2O4. Such products are of less harmful effect to the natural environment and can also be of beneficial use with their good mechanical properties identified by nano-indentation. We proved the possibility and provided an opportunity to convert the waste from wastewater treatment process to a new material resource. XRD is preferred for characterizing solid mixtures to determine the relative abundances of crystalline phases during the reaction process. As a result, we can obtain the relative abundance information on the growth of the crystalline products, such as CdAl4O7, and CdFe2O4 according to the change of fabrication temperatures. In that case, the starting reaction temperature and the optimized temperature (at which the completed reaction could be achieved) could be revealed. In Cd-Al system, the starting temperature for CdAl4O7 formation is 900 °C, and the optimized formation temperature is around 1020 °C. On the other hand, for Cd-Fe system, such temperatures are of 700 °C and 850 °C correspondingly. In our research, it is shown that the ceramic-process is an effective strategy to stabilize the waste hazardous metals (cadmium and nickel) by materials such as aluminate, ferrite, and kaolin commonly used in ceramic industry. Through this method, the difficult-to-treat wasted metals would become reusable and applied in building and infrastructure projects. Products containing CdAl4O7, CdFe2O4 and NiAl2O4 have shown higher resistance to acidic leaching, comparing to CdO and NiO used as the starting materials to simulate the waste metal forms discharged from the industrial stream. Furthermore, similar measurements by alkaline attack on the sintered products (NiAl2O4 containing samples) were also studied. Besides the investigation to leaching behavior, the mechanical properties are also measured by nano-indentation in our work. The incorporation of metal waste into the fabrication of ceramic products is valuable due to the preferred stabilization mechanisms of crystal structures and the large volume of ceramic products needed by the construction industry. Furthermore, because the product safety and functionality should not be compromised, a fundamental understanding of the surface properties of metal containing phases should be further established, rather than relying solely on data from regulatory tests on bulk samples. Therefore, the results of this study demonstrate the superior mechanical properties of nickel spinel containing products, comparing to the cristobalite silica matrix, under severe acid attack.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.source.urihttp://hub.hku.hk/bib/B47753067-
dc.subject.lcshX-ray crystallography.-
dc.subject.lcshNanotechnology.-
dc.subject.lcshNickel - Environmental aspects.-
dc.subject.lcshCadmium - Environmental aspects.-
dc.subject.lcshCeramic materials - Environmental aspects.-
dc.titleCharacterization of metal stabilization effect by X-ray diffraction technique and nano-indentation-
dc.typePG_Thesis-
dc.identifier.hkulb4775306-
dc.description.thesisnameMaster of Philosophy-
dc.description.thesislevelMaster-
dc.description.thesisdisciplineCivil Engineering-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b4775306-
dc.date.hkucongregation2012-

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