| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 106 === Beaded activated carbon (BAC) synthesized using bamboo tar as a precursor was examined for its ability to capture volatile organic compounds (VOCs). The effects of CO2 activation temperature and duration on the morphologies and pore structures developed were evaluated using N2 adsorption, elemental analysis, (EA) and scanning electron microscope (SEM). The self-prepared beaded activated carbons (SBAC) with the most robust adsorption performances were selected to compare with commercial beaded activated carbon (KBAC) in a fixed-bed adsorption test using toluene (TOL) and methylehtylketone (MEK) as probing molecules. The results revealed that the obtained specific surface area (684 – 1364 m2 g-1) and pore volume (0.376 – 0.751 cm3 g-1) both increased with the reaction temperature and duration. The adsorbents obtained were highly microporous. The adsorption capacities of both adsorbates correlated linearly with the specific surface area and pore volume. Three isotherm models, Langmuir, Freundlich, and Dubinin-Radushkevich (D-R), were fitted with the experimental results. It was found that Langmuir (R2 > 0.986) and D-R (R2 > 0.943) models showed better suitabilities compared with Freundlich model (R2 > 0.915). The isosteric heat of adsorption calculated using Clausius-Clapeyron (C-C) equation and D-R parameters ranged from 44.04 – 51.50 KJ mol-1 and 45.88 – 73.27 KJ mol-1 for MEK and TOL, respectively. It was concluded that the interactions between adsorbate and adsorbent evaluated in this study followed a physisorption nature. Yoon-Nelson (Y-N) model also successfully fitted our results, which can be useful in predicting breakthrough times in an actual adsorber. Finally, the microwave heating was applied to regenerate the saturated adsorbents. It was found that within eight minutes of microwave irradiation (600 W), the regeneration efficiencies of MEK reached 93.03 – 100% for the selected adsorbents. All the samples were able to sustain the adsorption capacities after ten cycles of microwave regenerations, proving both the uniqueness and the feasibility of this new technology. Overall, this study demonstrated the possibility of simultaneously solving two environmental issues, the waste management and the air pollution control.
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