不同特性的多孔炭对CO_2的吸附研究

CO_2 adsorption on porous carbons with different characteristics

分别用苯胺和糠醇为碳源、NaY分子筛为硬模板在碳化温度为700与900℃下合成了多孔炭（MC-AN-700、MC-AN-900、MC-FA-700和MC-FA-900）,并对材料进行了结构表征,研究了低浓度CO2在这些材料和商业活性炭（AC）上的动态吸附.结果显示,MC-AN-700的氮和氧的含量均最高,分别为6.59%和8.71%;MC-FA-900的总孔容居于首位,为0.73cm^3/g,但微孔体积中,AC的最大,为0.35cm^3/g.在常温常压下,初始浓度为10%的CO2在5种材料上的饱和吸附量的顺序为：MC-AN-700（2.20mmol/g）〉MC-AN-900（1.72mmol/g）〉AC（1.59mmol/g）〉MC-FA-900（1.45mmol/g）〉MC-FA-700（1.09mmol/g）,吸附差异受吸附剂的微孔孔容和氮含量共同影响.在2%～10%的范围内,CO2吸附量随初始浓度增加而增加;在20、45和65℃3个温度下,CO2吸附量随温度升高而降低.经4次脱附再生后,MC-AN-700的吸附量仍保持了原有吸附量的91%,高于MC-FA-900（86%）与AC（85%）.

Four porous carbons（MC-AN-700, MC-AN-900, MC-FA-700and MC-FA-900） were prepared using NaY zeolite as a hard template and aniline or furfuryl alcohol as carbon resources, respectively, which were carbonized at 700 ℃ or 900℃. The characteristics of the porous carbons were investigated by powder X-ray diffraction, elemental analysis and N2 adsorption. Low-concentration CO2 dynamic adsorption on the synthesized carbons and a commercial activated carbon（AC） as a comparative adsorbent was studied. Characterization results reveal that the nitrogen and oxygen contents of MC-AN-700are 6.59% and 8.71%, respectively, which are the highest among the five adsorbents. Additionally, MC-FA-900has the most total pore volume（0.73cm^3/g） while the micropore volume of AC（0.35cm^3/g） is the most. At atmosphere pressure and room temperature, CO2 saturated adsorption amount with initial concentration of 10% follows an order of MC-AN-700（2.20mmol/g）〉MC-AN-900（1.72mmol/g）〉AC（1.59mmol/g）〉 MC-FA-900（1.45mmol/g） 〉MC-FA-700（1.09mmol/g）, resulting from the combined effects of micropore volume and nitrogen content. With concentrations ranging between 2% and 10%, CO2 adsorption amount increases when initial concentration is raised. For different temperatures such as 20℃, 45℃ or 65℃, low temperature is advantageous to enhancing CO2adsorption. After four times desorption, 91% of the original CO2 adsorption amount on MC-AN-700is kept, which is higher than that on MC-FA-900（86%） and AC（85%）.