| Summary: | 碩士 === 國立臺灣科技大學 === 材料科學與工程系 === 102 === This study reported the fabrication of alkali-metal carbonates doped MgO powder. MgO itself is a promising adsorbent to capture CO2 due to its natural basic strength on the surface of the particle and its performance is well controlled by its morphology, surface area and surface structure. However, commercial MgO has very low sorption ability of 0.04 mmol/g sorbents at 300oC. Addition of alkali-metal carbonates (Cs2CO3) has been shown to exhibit the adsorption capacities. Ultrasonic spray pyrolysis was conducted to synthesize Cs2CO3 doped MgO powder simultaneously. As the matrix, MgO powder was prepared from Mg(CH3COO)2.4H2O precursor and Cs2CO3 were prepared as the dopant source. The adsorbent was characterized using X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA) and N2 adsorption desorption (BET) to measure the specific surface area. The morphology of the particle was observed using scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Based on these characterizations, it was shown that Cs2CO3 deposition on MgO surface exhibit higher CO2 adsorption capacity than undoped MgO and/or commercial MgO. The optimum concentration of Cs loading is 20 molar% Cs which successfully achieved 1.4 mmol CO2 per gram sorbents. Irregular shape particle and mixed compound of magnesium – cesium carbonate phase has been found to be responsible for the improvement of sorption capacity of the Cs2CO3-doped MgO powder. To the best of our findings, it is suggested that higher CO2 sorption can be achieved if cesium is uniformly dispersed throughout MgO matrix.
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