采用硝化一还原法对高比表面积活性炭进行改性以提高其对CO2的吸附性能。利用氮吸附、FT—IR、元素分析、XPS等方法对改性前后的样品进行表征,并通过高压吸附装置测试CO2吸附性能。结果表明,改性样品对CO2的吸附量在室温下和319.15K下分别为17.72mmol/g和14.01mmol/g,比原样分别提高了49%和70%(单位比表面积吸附量的增加幅度),这可能与改性样品的表面连接了碱性较强的伯氨基等含氮官能团有关。改性样品经4轮缓和条件下的吸附一脱附循环后,吸附量未明显下降,表明改性样品仍以物理吸附为主。
Activated carbon was oxidized by an acid mixture of concentrated HNO3 and H2 SO4 with a volume ratio of 1:1 diluted with the same volume of de-ionized water, followed by reduction with iron dust to modify its surface chemical properties for CO2 ad- sorption The samples before and after the modification were characterized by N2 adsorption, elemental analysis, FT-IR and XPS. CO2 adsorption properties of the samples were investigated by high pressure adsorption. It was found that the adsorption capacities of the modified sample were 17.72 and 14.01 mmol/g at room temperature and 319.15 K respectively, showing an increase of 49 and 70% respectively, based on the surface area of the samples. The modified activated carbon can be recycled 4 times at ambient condi- tions without a significant decrease in CO2 adsorption capacity. Surface basic nitrogen-containing functional groups on the modified sample, such as primary amino groups, are responsible for the increased adsorption.