| With the development of industrial production and population explosion growth, petrochemical resource is excessively consumed and the consequent environmental problem such as "greenhouse effect" is pushed to our face. The development and utilization of clean gaseous energy such as hydrogen and methane, as well as the environmental protection with carbon dioxide emissions and management have become urgent problems. At present, one of the effective strategies for gas recovery and utilization is to find suitable materials that can absorb these carbon-contained gases. Porous solid materials with large specific surface area and rich pore structure have displayed good performance on gas adsorption, separation and storage, because of their strong adsorption, high thermal stability, non-pollution and low-cost. In this thesis, we synthesized three kinds of porous solid materials, including boron nitride, alumina and metal-organic frameworks MIL-53(Al), and studied their adsorption performance on carbon dioxide and methane gas. The results were summarized as follow:(1) Hexagonal boron nitride was synthesized in a flow of ammonia gas at different temperatures. Then the adsorption properties of as-synthesized ammonification boron nitride for carbon dioxide and methane were investigated. In addition, porous and activate boron nitride were also synthesized and their adsorption performances were evaluated and compared with the ammonification boron nitride. The temperature of thermal treatment in ammonia atmosphere strongly affects the crystallinity, microstructure, thermal stability and pore structure of the synthesized boron nitride. The ammonothermal sample at 1400°C has the largest specific surface area and pore volume, i.e. 574.24 m2/g and 0.33 cm3/g respectively. Compared with the porous boron nitride and activated boron nitride, a much higher adsorption capacity of ammonification boron nitride for carbon dioxide and methane was obtained, which should result from the ammonia-treatment.(2) Mesoporous ?-Al2O3 was synthesized by a new method. The results showed that the mesoporous ?-Al2O3 presented nanowire morphology. Its specific surface area was measured to be up to ~120 m2/g. Carbon dioxide and methane adsorption capacity were measured as 0.7 mmol/g and 0.06 mmol/g at 0°C and atmosphere pressure. Its hydrogen storage capacities are extremely as high as 5.57 wt% at 77 K and 1.51 wt% at room temperature. At the same time, the formation mechanism of the ?-Al2O3 nanowires were discussed.(3) Metal-organic frameworks MIL-53(Al) was synthesized using aluminum chloride as metal source at 190°C, and has CO2-adsorption capacity 4.49 mmol/g which was higher than the highest CO2-adsorption capacity of mesoporous carbon(2.25 mmol/g) at atmosphere pressure. The additional acid as coordinate modulation during the hydrothermal synthesis was very important in the synthesis of MIL-53(Al) with well-crystallized, high yield, microstructure, the uniform poresize, high thermal stability as well as high surface areas. Especially, MIL-53(Al) with the addition of hydrochloric acid was a potential adsorbent for low-concentration CO2 capture, and had higher adsorption capacity for carbon dioxide and methane gas than that of samples synthesized without acid and with acetic acid.(4) The three kinds of porous adsorption materials showed different gas adsorption abilities. Carbon dioxide and methane adsorption on the metal-organic framework materials MIL-53(Al) were much stronger than that on porous boron nitride and aluminum oxide. Besides, the carbon dioxide adsorption was stronger than methane for three kinds of materials. |
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