活性炭微结构与吸附、解吸CO_2的关系

Effect of adsorption and desorption CO_2 on micro-structures of activated carbon

采用6种不同活性炭,在常压动态吸附装置中研究0,15,25和38℃时活性炭对CO2的吸附及解吸性能。通过CO2和N2的吸附等温线表征活性炭的孔隙结构,用红外光谱和Boehm滴定法表征活性炭的表面化学性质。结果表明：微孔孔容的大小是决定活性炭对CO2吸附性能好坏的关键因素,其中0.5~1.0 nm的微孔对CO2吸附能力的影响较大,同时2.0~4.5 nm的中孔也对CO2吸附有积极的贡献,温度升高使活性炭的吸附和解吸速率都加快,活性炭表面官能团中羧基和羟基对CO2的吸附有明显的促进作用,而羰基不利于解吸。

The adsorption and desorption properties of carbon dioxide（ CO2 ） on six activated carbons were investigated at 0,15,25,38℃ in an atmospheric dynamic adsorption reactor. The adsorbents were characterized by CO2 and N2 ad- sorption isotherms, FT-IR analysis and Boehm titration. The results show that micropore volume of activated carbons is an important factor to characterize the adsorption performance of CO2, the pore size distribution in the range of 0. 5- 1.0 nm or 2.0-4. 5 nm trend to enhance the adsorption of CO2. The rate of adsorption or desorption increases with the increase of temperature. The adsorption capacity of CO2 increases with an increase of carboxyl and hydroxy groups on activated carbons. However,the increase of carbonyl groups would reduce the desorption capacity of CO2.