活性炭吸附苯、甲苯废气的研究

Adsorption of Benzene and Toluene Vapour on Activated Carbon

研究了苯、甲苯组成的混合溶剂系统的吸附平衡关系及动力学性质。采用动态吸附法对纯组分、混合组分的吸附情况进行了测定。 根据Langmuir方程拟合出相应的平衡常数qe和K。通过对二组分吸附的穿透曲线进行分析,发现吸附能力强的甲苯能从活性炭中置换出吸附能力弱的苯。整个吸附过程分为三个阶段进行。分别利用E-L方程和IAST理论进行理论预测分析,并与实验结果进行了比较。结果表明,虽然E-L方程对吸附总量的预测与实验结果较为吻合,但对各个组分吸附量的预测却经常产生正负偏差;而IAST引入竞争模型,较好地消除了这种正负偏差,平均误差不超过10%,与实验结果更为吻合。

Dynamic adsorption was used to measure the adsorption of benzene and toluene as well as their gas mixture. Analysis of breakthrough curves of binary mixture indicates that the whole adsorption process can be divided into three stages and strong component(toluene)can replace weaker component(benzene)in the adsorbent(activated carbon). The extended Langmuir equation (E-L) and the ideal adsorbed solution theory (IAST) were used respectively to predict the results of the adsorption, and the prediction of multicomponent adsorption with E-L equation and IAST were compared with experimental data. The result shows that the total adsorption capacity obtained by E-L equation fixes experimental data well but has deviation in the calculation of pure components. Whereas this violation is reduced to less than 10% by IAST in which the competitive adsorption of different components in the same adsorbent is considered. The experiments show that IAST describes the total adsorption equilibrium sufficiently well.