摘要
把氢氧化钾活化的石油焦基活性炭进行浓硫酸氧化,并对氧化物进行热处理,得到不同氧含量的活性炭,并用氮气物理吸附和XPS对活性炭的孔及其表面化学官能团进行了表征.研究了二氧化碳在不同氧含量活性炭上的吸附平衡容量随温度的变化以及氧含量对于二氧化碳吸附容量的影响.结果表明:在25℃～175℃和0.001MPa～1.5MPa的范围内,二氧化碳在活性炭上的吸附可以用Langmuir方程很好地描述,饱和覆盖度和黏附系数均随温度的升高而下降,吸附热随活性炭的氧化和热处理变化很小.随活性炭O/C比的增加,饱和覆盖度下降,而黏附系数增加.适合二氧化碳吸附的活性炭应具有适中的O/C比,O/C比太大和太小均不利于二氧化碳的吸附.
Activated carbon from petroleum coke by KOH activation was oxidized by concentrated sulfuric acid at 170 ℃ for 3 h,followed by heat treatment under protection of nitrogen at 450 and 750 ℃ for 3 h.The as-activated carbon,oxidized activated carbon and heat-treated carbon with different oxygen contents were characterized by nitrogen adsorption and X-ray photoelectron spectroscopy,and their adsorptive capacities for CO2 at 25 ℃ to 175 ℃ and 10 mbar to 15 000 mbar were investigated.It was found that their BET surface areas and pore size distributions were similar while their surface oxygen contents were different depending on the oxidation and heat treatment conditions.The adsorptive capacities for CO2 in the experimental conditions can be well fitted by Langmuir equation.The monolayer capacity and sticking coefficient decreased with adsorption temperature and the heat of adsorption changed little with the oxidation or heat treatment.The monolayer capacity decreased and sticking coefficient increased with O/C atom ratios.Suitable activated carbon should have a moderate O/C ratio for a better adsorption for CO2.
出处
《煤炭转化》
CAS
CSCD
北大核心
2011年第4期57-61,共5页
Coal Conversion
基金
国家自然科学基金资助项目(50872033)
中国科学院炭材料重点实验室开放基金资助项目(KFJJ0903)
煤转化国家重点实验室基金资助项目(09-610)
关键词
活性炭
表面化学结构
孔分布
二氧化碳吸附
activated carbon
surface functionality
pore distribution
CO2 adsorption
