| Summary: | 碩士 === 逢甲大學 === 材料科學學系 === 88 === In this study, we used the oxidation PCI(Pulverized Coal Injection) coal to produce different kinds of coal-based activated carbons which had water activation treatment after high temperature (800℃) or low temperature (600℃) pre-carbonization treatment. And then followed with the discussion of the effect of this method on the physical properties and the microstructure of the resultant activated carbon.
First, the thermal gravity analysis (TGA) was carried out to get the result of the weight loss and the exothermic reaction or the endothermic reaction of the PCI precursor and the oxidation treatment carbon material. Next element analysis (EA) and Fourier-transform infrared (FT-IR) were applied to reveal the volatile matters from carbon material. Then, the inner microstructure was also investigated by Raman laser scattering and true density spectra. As for the effect of activation on the pore diameter size and the specific surface area of carbon was analyzed by nitrogen adsorption and desorption at 77K, we were informed of the pore structure of activated carbons which had gotten through oxidation, high temperature (800℃) and low temperature (600℃) pre-carbonization treatment. Final with Scanning Electron Microscope (SEM) analysis, we detected out change of the shapes and particle sizes of carbon materials as the followings.
We discovered that not only the rate of weight loss after the oxidation treatment became slow but also oxygen contents obviously increased. From Raman laser scattering analysis, the average length of carbon layers (La) increased the rise of the with carbonization treatment temperature, but decreased with the rise of the activation treatment temperature. The outcome of the experiment of nitrogen adsorption and desorption claimed higher activation treatment temperature resulted in the decrease of pore size, from macropore through mesopore to micropore, especially the activated carbons after oxidation treatment and higher temperature pre-carbonization treatment revealed to be the best ones with a specific surface area 557m2/g. Furthermore, from the scanning electron microscope (SEM) pictures of carbon materials, we knew particle sizes of the oxidation PCI precursor would become bigger, so did the bigger specific surface area.
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