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postgraduate thesis: Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation
Title | Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation |
---|---|
Authors | |
Advisors | Advisor(s):Shih, K |
Issue Date | 2011 |
Publisher | The 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 |
Abstract | The 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. |
Degree | Master of Philosophy |
Subject | X-ray crystallography. Nanotechnology. Nickel - Environmental aspects. Cadmium - Environmental aspects. Ceramic materials - Environmental aspects. |
Dept/Program | Civil Engineering |
Persistent Identifier | http://hdl.handle.net/10722/174486 |
HKU Library Item ID | b4775306 |
DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Shih, K | - |
dc.contributor.author | He, Yue | - |
dc.contributor.author | 贺悦 | - |
dc.date.issued | 2011 | - |
dc.identifier.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 | - |
dc.identifier.uri | http://hdl.handle.net/10722/174486 | - |
dc.description.abstract | The 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.language | eng | - |
dc.publisher | The University of Hong Kong (Pokfulam, Hong Kong) | - |
dc.relation.ispartof | HKU Theses Online (HKUTO) | - |
dc.rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works. | - |
dc.rights | This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. | - |
dc.source.uri | http://hub.hku.hk/bib/B47753067 | - |
dc.subject.lcsh | X-ray crystallography. | - |
dc.subject.lcsh | Nanotechnology. | - |
dc.subject.lcsh | Nickel - Environmental aspects. | - |
dc.subject.lcsh | Cadmium - Environmental aspects. | - |
dc.subject.lcsh | Ceramic materials - Environmental aspects. | - |
dc.title | Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation | - |
dc.type | PG_Thesis | - |
dc.identifier.hkul | b4775306 | - |
dc.description.thesisname | Master of Philosophy | - |
dc.description.thesislevel | Master | - |
dc.description.thesisdiscipline | Civil Engineering | - |
dc.description.nature | published_or_final_version | - |
dc.identifier.doi | 10.5353/th_b4775306 | - |
dc.date.hkucongregation | 2012 | - |
dc.identifier.mmsid | 991033467509703414 | - |