KOH活化制备烟杆基活性炭的炭化过程

Carbonization process in preparation of activated carbon from tobacco stems with KOH-activation

为了揭示KOH活化烟杆制备活性炭中炭化阶段的反应机理,利用热重法对氮气气氛中烟杆和浸渍KOH的烟杆在不同升温速率下(分别为5,15,30 K/min)的热解过程进行了研究。结果表明,随着KOH的加入,降低了烟杆主要成分的分解温度,为炭化之后的活化反应奠定了重要基础。采用Coats-Redfern模型对实验数据进行处理,得出了烟杆和添加KOH的烟杆的热解表观活化能和指前因子,建立了热解动力学模型,发现烟杆及添加KOH的烟杆热解的主要阶段分别可由一段1级反应和2.5级反应过程描述,KOH的存在可将烟杆炭化阶段的活化能降低约30 kJ/mol,动力学参数存在补偿效应。

In order to reveal the mechanism of carbonization process in preparation of activated carbon from tobacco stems with KOH-activation, the pyrolytic process of tobacco stem and that impregnated with KOH was carried out by using thermo-gravimetric analyzer at different heating rates of 5, 15, 30 K/min in N2 atmosphere. The temperature of pyrolytic reactions of main component of tobacco stems can be reduced in the presence of KOI-I, which lays the important foundation of the activation reaction afterward. Coats-Redfern model was used to determine the kinetic parameters for the tobacco stems with/without KOH, including frequency factors and activation energies. The pyrolytic kinetic models of two samples were set up. The main pyrolytic stages can be described by first-order and 2.5-order global model, respectively. The results indicate that the pyrolysis activation energy can be lowered by about 30 kJ/mol in the present of KOH, and the kinetic parameters exhibit compensation effects.