CH_4/N_2在PVDF基微孔炭上的吸附分离研究

Research of adsorption separation of CH_4/N_2 on PVDF-based microporous carbon

通过热解聚偏氟乙烯(PVDF)一步法制备微孔炭,并借助N_2吸脱附、XRD等对其结构进行表征,利用磁悬浮天平测量了甲烷(CH_4)/氮气(N_2)的吸附等温线,并进行Langmuir和Freundlich拟合,并由Henry常数预测CH_4/N_2的分离因子。结果表明:吸附等温模型拟合效果较好,当温度为45℃,分离因子为4.59,有较好的分离效果;对吸附热力学进行研究表明CH_4的吸附热大于N_2,说明吸附剂对CH_4的吸附作用力大于N_2,且相对分子筛类吸附剂吸附热较小,易于吸附剂的再生。

The microporous carbon was prepared by pyrolysing the poly（ vinylidene fluoride） and characterized by N2 adsorption,as well as used XRD to analyze the structure. Adsorption isotherm of CH4/N2 were measured by magnetic suspension balance. The Langmuir and Freundlich model were used to fit the experimental data and the data could be well fitted by both models.The separation coefficient of CH4/N2 calculated from the Henry constant reached 4. 59 at 45℃,which meant a better separation result. The isosteric heat of adsorption of CH4 was greater than N2 via the study of adsorption thermodynamics,indicating that the adsorbent had stronger affinity on CH4 than N2. Compared with other zeolite-like adsorbents,the isosteric heat was lower,which meant a facile regeneration.