活性炭的孔径分布对CH_4和CO_2的吸附性能的影响  

Effect of Pore Size Distribution on Adsorption Capacities of Activated Carbons for CH_4 and CO_2

作　　者：杨皓[1] 龚茂初[1] 陈耀强[1] 

机构地区：[1]四川大学绿色化学与技术教育部重点实验室,成都610064

出　　处：《无机化学学报》2011年第6期1053-1058,共6页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.20773090)资助项目

摘　　要：采用不同炭化温度和活化温度,以椰壳作为前驱体制备了系列结构性能相同,表面吸附基团相似,不同孔结构的活性炭。分别采用密度函数理论(DFT)吸附法和BJH估算了系列活性炭的孔径分布。结果表明,随炭化温度和活化温度的升高系列活性炭中微孔量先增加后减少。当炭化温度为700℃,活化温度为800℃时,制备的活性炭微孔量达到最大。随炭化温度和活化温度的升高,系列活性炭的中孔依次增加。考查了CH4,CO2在系列活性炭上的吸附性能。结果表明该系列活性炭对CO2有很强的吸附能力,在常温常压下对CO2的吸附量均高于1.0 mmol.g-1;系列活性炭对CH4的吸附能力有较大的差异,在对CO2具有最大吸附量的活性炭上对CH4具有最小的吸附量。采用变压吸附法测试了该系列活性炭在25℃时对nCH4∶nCO2=9∶1的混合气体的分离性能。结果表明炭化温度为700℃,活化温度为800℃时制备的活性炭对CH4-CO2混合气具有最好的分离效果,是变压吸附分离CH4,CO2混合气的优异吸附剂。A series of activated carbons were prepared using coconut-shells as carbon precursor with different carbonization and activation temperatures.The activated carbons have almost the same structure properties and no adsorbed organic groups on the surface.The density functional theory（DFT） and BJH methods were used to estimate the pore size distribution of the activated carbons.The results reveal that the content of the micro-pores increase and then decrease with increase in temperature,and the content reaches to the maximum when the carbonization temperature is up to 700 ℃ and activation temperature elevates to 800 ℃.The mesopores increase with the increase of the temperature.The adsorption capacities of CH4,CO2 were tested at room temperature.The results suggest that the activated carbons have high adsorption capacity,more than 1.0 mmol·g-1,however,that of CH4 differs a lot.The activated carbons were applied to adsorption separation of CH4/CO2 mixed gas with molar ratio of 9 by pressure swing adsorption technology.The results show that the activated carbons have excellent property of adsorption separation of CH4/CO2 mixed gas at room temperature,especially for AC-2 carbonized at 700 ℃ activated at 800 ℃.

关 键 词：活性炭 变压吸附 天然气 二氧化碳 

分 类 号：O613.71[理学—无机化学] O647.313[理学—化学]