| Summary: | 碩士 === 明新科技大學 === 化學工程與材料科技系碩士班 === 101 === Ni-Zn ferrite with a composition of Ni1-x-yZnxFe2O4, are indispensable components in electrical circuit. More than ten thousand tons are needed in the whole world annually. Traditionally the ferrites are prepared by solid-state reaction method from oxides such as NiO, ZnO, Fe2O3 as raw materials. The materials’ cost is more then NT$100/kg, in which more than 85% is nickel’s cost. If cheaper nickel can be found, it will extensively reduce the raw materials’ cost. In this research project a waste nickel containing catalyst will be used in producing Ni-Zn ferrite.
The nickel containing filtrate obtained accompanying with iron containing spent pickling acid, and zinc nitrate, as nickel, iron, and zinc sources, and alkali as neutralizing agent, Ni-Zn ferrite powders were produced by chemical co-precipitation method. In this process not only raw materials were much cheaper, but also processing fee may be collected from government for the waste materials. The quantity of these waste materials are very large. It is enough for producing Ni-Zn ferrites. Therefore it is very meaningful from the view points of material reutilization,
earth’s resources saving, and environmental pollution reduction.
Experimental process by using acid or ammonia process was used. The nickel ions in nickel-containing waste catalyst were dissolved from the solid waste into the acid solution. Then by using Ni as the basis in the nickel-containing solution, adjust the calculated composition and make up the deficiency of zinc and iron. Later, adding alkali into the solutions and heating the solutions to weak alkali, nickel、iron and zinc ions were precipitated out from the solution as amorphous hydroxides and slowly transform to crystalline spinel Ni-Zn ferrite powders. The powders were filtered, dried , ground and calcined to obtain magnetic Ni-Zn ferrite powders.
Experimental treatment by using photocatalyst-TiO2 alone for dye wastewater is proven to be very efficient. Besides, the secondary pollution by the application of other advanced treatment methods can be eliminated. But, the difficulty of solids (TiO2 ) and liquid (wastewater) separation problems exists and hard to solve. Therefore, this study will use titanium sulfate、urea and Ni-Zn ferrite powder to produce modified titanium dioxide photocatalyst by coprecipitation mothod. Finally by filtration , drying , grinding and calcinations, magnetic photocatalyst powder was obtained. These magnetic photocatalysts can be recovered by the application of the magnetic field.
The characterization of the prepared Ni-Zn ferrite power and modified magnetic photocatalysts with their application in the dye wastewater treatment under UVA irradiation was investigated by using AA﹐XRF﹐XRD﹐SEM﹐DLS﹐SQUID﹐TOC and colorimeter. The Langmuir adsorption isotherm and Langmuir-Hinshelwood kinetic model were proven to be applicable to the FBL dye wastewater treatment by using these photo magnetic Ni-Zn ferrite/TiO2 catalysts under UVA irradiation.
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