煤基活性炭孔径分布的调控

提出并研究了一种煤基活性炭孔径分布的调控方法及调控机理.将煤样与不同质量的KOH混合后炭化,分别对炭化料进行酸洗,以控制其中的钾含量,然后对酸洗料进行蒸汽活化,制成活性炭.通过对所制活性炭进行氮气吸附实验、扫描电镜及能谱分析和吸附能力表征实验后发现:改变KOH加入量和采用质量浓度为5%的盐酸对炭化料进行酸洗,能够改变炭化料中的钾含量;随着KOH含量的提高,活性炭的口发附能力逐渐增强,平均孔径从2.379 nm逐渐增大到2.636nm,同时孔径分布由以微孔为主逐渐向以中孔为主转移,其中孔含量由30.9%提高到46.1%.

Regulation of pore size distribution in coal-based activated carbon

An approach to regulating the pore size distribution of coal-based activated carbon was proposed and studied by potassium-catalyzed steam activation. Activated carbons were prepared from coal in the presence of different amounts of KOH in the raw materials, and in the process of which, delicate acid washing was performed to change the amount of K-containing compounds left in chars after carbonization and before steam activation. Then, the activated carbons were characterized by nitrogen adsorption, scanning electron microscopy, and X-Ray energy spectrometry, and their adsorp-tion capacity was determined. Results show that the content of K-containing compounds left in the char can be controlled jointly by changing the amount of KOH added to the precursor and subsequent washing with 5% mass fraction acid after carbonization. With increasing amount of KOH, the adsorption capacity of the resulting activated carbon becomes grea-ter. The average pore size of the activated carbons gradually increases from 2.379 to 2.636nm, and the mesoporosity in-creases from 30.9 to 46.1%. The principles for the regulation of pore size distribution in activated carbon were dis-cussed.